Coastline of the Sea of ​​Okhotsk. The Sea of ​​Okhotsk has become an inland sea of ​​Russia

The Sea of ​​Okhotsk is a sea of ​​the Pacific Ocean, separated from it by the Kamchatka Peninsula, the Kuril Islands and the island of Hokkaido.
The sea washes the shores of Russia and Japan.
Area - 1603 thousand km². The average depth is 1780 m, the maximum depth is 3916 m. The western part of the sea is located above the gentle continuation of the continent and has a shallow depth. In the center of the sea are the Deryugin depression (in the south) and the TINRO depression. In the eastern part there is the Kuril Basin, where the depth is maximum.

Sea of ​​Okhotsk map of the Far East

In the chain of our Far Eastern seas, it occupies a middle position, protrudes quite deeply into the Asian continent, and is separated from the Pacific Ocean by the arc of the Kuril Islands. The Sea of ​​Okhotsk has natural boundaries almost everywhere and only in the southwest from the Sea of ​​Japan it is separated by conventional lines: Cape Yuzhny - Cape Tyk and in the La Perouse Strait Cape Crillon - Cape Soya. The southeastern border of the sea runs from Cape Nosyappu (Hokkaido Island) through the Kuril Islands to Cape Lopatka (Kamchatka), while all passages between the island. Hokkaido and Kamchatka are included in the Sea of ​​Okhotsk. Within these limits, the sea extends from north to south from 62°42′ to 43°43′ N. w. and from west to east from 134°50′ to 164°45′ E. d. The sea is significantly elongated from southwest to northeast and expanded approximately in its central part.

GENERAL DATA, GEOGRAPHY, ISLANDS
The Sea of ​​Okhotsk is one of the largest and deepest seas in our country. Its area is 1603 thousand km2, volume 1318 thousand km3, average depth 821 m, greatest depth 3916 m. According to its geographical location, the predominance of depths up to 500 m and significant spaces occupied by great depths, the Sea of ​​Okhotsk belongs to the marginal seas of mixed continental- marginal type.

There are few islands in the Sea of ​​Okhotsk. The largest border island is Sakhalin. The Kuril ridge has about 30 large and many small islands and rocks. The Kuril Islands are located in a belt of seismic activity, which includes more than 30 active and 70 extinct volcanoes. Seismic activity occurs on the islands and underwater. In the latter case, tsunami waves are formed. In addition to the named “marginal” islands in the sea there are the islands of Shantarskie, Spafareva, Zavyalova, Yamskie and the small island of Jonah - the only one of them remote from the coast.
Although the coastline is long, it is relatively weakly indented. At the same time, it forms several large bays (Aniva, Terpeniya, Sakhalinsky, Akademii, Tugursky, Ayan, Shelikhova) and bays (Udskaya, Tauyskaya, Gizhiginskaya and Penzhinskaya).

Atsonopuri volcano, Iturup island, Kuril Islands

From October to May - June, the northern part of the sea is covered with ice. The southeastern part practically does not freeze.

The coast in the north is strongly indented; in the northeast of the Sea of ​​Okhotsk its largest bay is located - Shelikhov Bay. Of the smaller bays in the northern part, the most famous are the Eirine Bay and the bays of Sheltinga, Zabiyaka, Babushkina, and Kekurny.

In the east, the coastline of the Kamchatka Peninsula is practically devoid of bays. In the west, the coastline is heavily indented, forming the Sakhalin Bay and the Shantar Sea. In the south, the largest are Aniva and Terpeniya bays, Odessa Bay on the island of Iturup.

Fishing (salmon, herring, pollock, capelin, navaga, etc.), seafood (Kamchatka crab).

Hydrocarbon production on the Sakhalin shelf.

The Amur, Okhota, and Kukhtui rivers flow into it.

Sea of ​​Okhotsk Cape Velikan, Sakhalin Island

Main ports:
on the mainland - Magadan, Ayan, Okhotsk (port point); on the island of Sakhalin - Korsakov, on the Kuril Islands - Severo-Kurilsk.
The sea is located on the Okhotsk subplate, which is part of the Eurasian plate. The crust under most of the Sea of ​​Okhotsk is of continental type.

The Sea of ​​Okhotsk is named after the Okhota River, which in turn comes from Evensk. okat - “river”. Previously it was called Lamsky (from Evensk. Lam - “sea”), as well as the Kamchatka Sea. The Japanese traditionally called this sea Hokkai (北海), literally "North Sea". But since now this name refers to the North Sea of ​​the Atlantic Ocean, they changed the name of the Sea of ​​Okhotsk to Ohotsuku-kai (オホーツク海), which is an adaptation of the Russian name to the norms of Japanese phonetics.

Cape Medyay Sea of ​​Okhotsk

Territorial regime
The Sea of ​​Okhotsk consists of internal waters, the territorial sea and the exclusive economic zone of two coastal states - Russia and Japan. In terms of its international legal status, the Sea of ​​Okhotsk is closest to a semi-enclosed sea (Article 122 of the UN Convention on the Law of the Sea), since it is surrounded by two or more states and mainly consists of the territorial sea and the exclusive economic zone of two states, but it is not such, since connected to the rest of the world's oceans not by a single narrow passage, but by a series of passages.
In the central part of the sea, at a distance of 200 nautical miles from the baselines, there is a section elongated in the meridional direction, traditionally called Peanut Hole in English literature, which is not included in the exclusive economic zone and is the open sea outside the jurisdiction of Russia; in particular, any country in the world has the right here to fish and conduct other activities permitted by the UN Convention on the Law of the Sea, excluding activities on the shelf. Since this region is an important element for the reproduction of the population of some species of commercial fish, the governments of some countries directly prohibit their vessels from fishing in this area of ​​​​the sea.

On November 13-14, 2013, the Subcommission created within the UN Commission on the Limits of the Continental Shelf agreed with the arguments of the Russian delegation as part of the consideration of the Russian Federation’s application to recognize the bottom of the above-mentioned area of ​​the high seas as a continuation of the Russian continental shelf. On March 15, 2014, the 33rd session of the Commission in 2014 adopted a positive decision on the Russian application, first submitted in 2001, and submitted in a new version at the beginning of 2013, and the central part of the Sea of ​​Okhotsk outside the exclusive economic zone of the Russian Federation was recognized continental shelf of Russia.
Consequently, in the central part, other states are prohibited from extracting “sessile” biological resources (for example, crab) and from subsoil development. The fishing of other biological resources, such as fish, is not subject to restrictions on the continental shelf. Consideration of the application on its merits became possible thanks to the position of Japan, which, with an official note dated May 23, 2013, confirmed its consent to the Commission’s consideration of the essence of the application, regardless of the resolution of the issue of the Kuril Islands. Sea of ​​Okhotsk

Temperature and salinity
In winter, the water temperature at the sea surface ranges from −1.8 to 2.0 °C; in summer, the temperature rises to 10-18 °C.
Below the surface layer, at depths of about 50-150 meters, there is an intermediate cold layer of water, the temperature of which does not change throughout the year and is about −1.7 °C.
The waters of the Pacific Ocean entering the sea through the Kuril Straits form deep water masses with a temperature of 2.5 - 2.7 °C (at the very bottom - 1.5-1.8 °C). In coastal areas with significant river flow, the water temperature in winter is about 0 °C, in summer - 8-15 °C.
The salinity of surface sea waters is 32.8–33.8 ppm. The salinity of the intermediate layer is 34.5‰. Deep waters have a salinity of 34.3 - 34.4 ‰. Coastal waters have a salinity of less than 30 ‰.

RESCUE OPERATION
Incident in December 2010 - January 2011
Icebreaker "Krasin" (built in 1976), an analogue of the icebreaker "Admiral Makarov" (built in 1975)

From December 30, 2010 to January 31, 2011, a rescue operation was carried out in the Sea of ​​Okhotsk, which received widespread media coverage.
The operation itself was large-scale; according to Deputy Minister of Transport Viktor Olersky and head of Rosrybolovstvo Andrei Krainiy, rescue operations on such a scale have not been carried out in Russia for 40 years.
The cost of the operation was between 150 and 250 million rubles, and 6,600 tons of diesel fuel were consumed.
15 ships carrying about 700 people were captured in the ice.
The operation was carried out by an icebreaker flotilla: the icebreakers Admiral Makarov and Krasin, the icebreaker Magadan and the tanker Victoria served as auxiliary vessels. The coordination headquarters of the rescue operation was located in Yuzhno-Sakhalinsk, the work was carried out under the leadership of the Deputy Minister of Transport of the Russian Federation Viktor Olersky.

Most of the ships got out on their own, icebreakers rescued four ships: the trawler "Cape Elizabeth", the research vessel "Professor Kiesewetter" (first half of January, "Admiral Makarov"), the refrigerator "Coast of Hope" and the floating base "Commonwealth".
The first help was provided to the seiner "Cape Elizabeth", whose captain sailed his ship after the ban on entry into the area was imposed.
As a result, “Cape Elizabeth” was frozen into ice in the Sakhalin Bay area. Sea of ​​Okhotsk

The second ship to be released was the Professor Kiesewetter, whose captain, as a result of the investigation, was deprived of his diploma for six months.
In the area of ​​January 14, icebreakers brought together the remaining vessels in distress, after which the icebreakers escorted both vessels of the caravan in a coupled manner.
After the “Whiskers” of the “Commonwealth” broke, it was decided to first move the refrigerator through the heavy ice.
The wiring was suspended in the area on January 20 due to weather conditions, but on January 24 it was possible to bring the Bereg Nadezhdy refrigerator into clean water.
On January 25, after bunkering, the Admiral Makarov returned to escort the mother ship.
On January 26, the towing “whiskers” broke again, and we had to lose time to deliver new ones by helicopter.
On January 31, the floating base "Commonwealth" was also removed from ice captivity; the operation ended at 11:00 Vladivostok time.

HOKKAIDO ISLAND
Hokkaido (Japanese: “Government of the North Sea”), formerly known as Ezo, in the old Russian transcription Iesso, Ieddo, Iedzo, is the second largest island of Japan. Until 1859, it was also called Matsumae after the surname of the ruling feudal clan, which owned the castle town of Matsumae - in the old Russian transcription - Matsmai, Matsmai.
It is separated from the island of Honshu by the Sangar Strait, but the Seikan Tunnel is built between these islands under the seabed. The largest city of Hokkaido and the administrative center of the prefecture of the same name is Sapporo. The northern coast of the island is washed by the cold Sea of ​​Okhotsk and faces the Pacific coast of the Russian Far East. The territory of Hokkaido is almost equally divided between mountains and plains. Moreover, the mountains are located in the center of the island and stretch in ridges from north to south. The highest peak is Mount Asahi (2290 m). In the western part of the island, along the Ishikari River (length 265 km), there is a valley of the same name, in the eastern part, along the Tokachi River (156 km) there is another valley. The southern part of Hokkaido forms the Oshima Peninsula, separated by the Sangar Strait from Honshu.
The easternmost point of Japan is located on the island - Cape Nosappu-Saki. The northernmost point of Japan is also located on it - Cape Soya.

Cape Krasny, Three Brothers Islands

SHELEKHOV BAY
Shelikhov Bay is a bay of the Sea of ​​Okhotsk between the coast of Asia and the base of the Kamchatka Peninsula. The bay received its name in honor of G.I. Shelikhov.
Length - 650 km, width at the entrance - 130 km, maximum width - 300 km, depth up to 350 m.
In the northern part of the peninsula, Taigonos is divided into Gizhiginskaya Bay and Penzhinskaya Bay. The rivers Gizhiga, Penzhina, Yama, and Malkachan flow into the bay.
Covered with ice from December to May. Tides are irregular, semidiurnal. In Penzhinskaya Bay they reach their maximum values ​​for the Pacific Ocean.
The bay is rich in fish resources. Fishing objects include herring, halibut, flounder, and Far Eastern navaga.
In the southern part of Shelikhov Bay there is a small archipelago of the Yamsky Islands.
In Shelikhov Bay, tides reach 14 m.

Sakhalin Bay, swans have arrived Sea of ​​Okhotsk

SAKHALIN GULF
Sakhalin Bay is a bay of the Sea of ​​Okhotsk between the coast of Asia north of the mouth of the Amur and the northern tip of Sakhalin Island.
In the northern part it is wide, to the south it narrows and passes into the Amur Estuary. Width up to 160 km, the Nevelskoy Strait is connected to the Tatar Strait and the Sea of ​​Japan.
From November to June it is covered with ice.
Tides are irregular daily, up to 2-3 m.
Industrial fishing (salmon, cod) is carried out in the waters of the bay.
The port of Moskalvo is located on the shore of the bay.

Aniva Bay, Korsakov port, Sakhalin Island

ANIVA BAY
Aniva is a bay of the Sea of ​​Okhotsk, off the southern coast of Sakhalin Island, between the Krillonsky and Tonino-Aniva peninsulas. From the south it is wide open into the La Perouse Strait.
The origin of the bay's name is most likely related to the Ainu words "an" and "iva". The first is usually translated as “available, located”, and the second as “mountain ridge, rock, peak”; thus, "Aniva" can be translated as "having ridges" or "located among ridges (mountains)."
Width 104 km, length 90 km, greatest depth 93 meters. The narrowed part of the bay is known as Salmon Bay. The warm Soya current influences the temperature regime and the dynamics of currents inside the bay, which are variable.

Sakhalin (Japanese: 樺太，Chinese: 库页/庫頁) is an island off the eastern coast of Asia. It is part of the Sakhalin region. The largest island in Russia. It is washed by the Seas of Okhotsk and Japan. It is separated from mainland Asia by the Tatar Strait (at its narrowest part, the Nevelskoy Strait, it is 7.3 km wide and freezes in winter); from the Japanese island of Hokkaido - the La Perouse Strait.

The island got its name from the Manchu name of the Amur River - “Sakhalyan-ulla”, which translated means “Black River” - this name, printed on the map, was mistakenly attributed to Sakhalin, and in subsequent editions of maps it was printed as the name of the island.

The Japanese call Sakhalin Karafuto, this name goes back to the Ainu “kamuy-kara-puto-ya-mosir”, which means “land of the god of the mouth”. In 1805, a Russian ship under the command of I. F. Krusenstern explored most of the coast of Sakhalin and concluded that Sakhalin was a peninsula. In 1808, Japanese expeditions led by Matsuda Denjuro and Mamiya Rinzou proved that Sakhalin is an island. Most European cartographers were skeptical of the Japanese data. For a long time, on various maps Sakhalin was designated either an island or a peninsula. Only in 1849 did an expedition under the command of G.I. Nevelsky put a final point on this issue, passing on the military transport ship “Baikal” between Sakhalin and the mainland. This strait was subsequently named after Nevelsky.

The island extends meridionally from Cape Crillon in the south to Cape Elizabeth in the north. Length 948 km, width from 26 km (Poyasok isthmus) to 160 km (at the latitude of the village of Lesogorskoye), area 76.4 thousand km².

BAY OF PATIENCE
Terpeniya Bay is a bay of the Sea of ​​Okhotsk off the southeastern coast of Sakhalin Island. In the eastern part it is partially limited by the Terpeniya Peninsula.
The bay was discovered in 1643 by the Dutch navigator M. G. De Vries and was named Terpeniya Bay by him, since his expedition had to wait out thick fog here for a long time, which made it impossible to continue sailing.
The length of the bay is 65 km, width is about 130 km, depth is up to 50 m. The Poronai River flows into the bay.
In winter the bay freezes.
The waters of the bay are rich in biological resources, including chum salmon and pink salmon.
The port of Poronaysk is located in Terpeniya Bay. Sea of ​​Okhotsk

- a chain of islands between the Kamchatka Peninsula and the island of Hokkaido, separating the Sea of ​​Okhotsk from the Pacific Ocean with a slightly convex arc.
Length - about 1200 km. The total area is 10.5 thousand km². To the south of them lies the state border of the Russian Federation with Japan.
The islands form two parallel ridges: the Greater Kuril and the Lesser Kuril. Includes 56 islands. They have important military-strategic and economic significance. The Kuril Islands are part of the Sakhalin region of Russia. The southern islands of the archipelago - Iturup, Kunashir, Shikotan and the Habomai group - are disputed by Japan, which includes them in Hokkaido Prefecture.

Belongs to the regions of the Far North
The climate on the islands is maritime, quite harsh, with cold and long winters, cool summers, and high humidity. The mainland monsoon climate undergoes significant changes here. In the southern part of the Kuril Islands, frosts in winter can reach −25 °C, the average temperature in February is −8 °C. In the northern part, winter is milder, with frosts down to −16 °C and −7 °C in February.
In winter, the islands are affected by the Aleutian baric minimum, the effect of which weakens by June.
The average August temperature in the southern part of the Kuril Islands is +17 °C, in the northern part - +10 °C.

List of islands with an area greater than 1 km² in a north-south direction.
Name, Area, km², height, Latitude, Longitude
Great Kuril Ridge
Northern group
Atlasova 150 2339 50°52" 155°34"
Shumshu 388 189 50°45" 156°21"
Paramushir 2053 1816 50°23" 155°41"
Antsiferova 7 747 50°12" 154°59"
Makanrushi 49 1169 49°46" 154°26"
Onekotan 425 1324 49°27" 154°46"
Kharimkotan 68 1157 49°07" 154°32"
Chirinkotan 6 724 48°59" 153°29"
Ekarma 30 1170 48°57" 153°57"
Shiashkotan 122 934 48°49" 154°06"

Middle group
Raikoke 4.6 551 48°17" 153°15"
Matua 52 1446 48°05" 153°13"
Rashua 67 948 47°45" 153°01"
Ushishir Islands 5 388 — —
Ryponkich 1.3 121 47°32" 152°50"
Yankich 3.7 388 47°31" 152°49"
Ketoy 73 1166 47°20" 152°31"
Simushir 353 1539 46°58" 152°00"
Broughton 7 800 46°43" 150°44"
Black Brothers Islands 37,749 — —
Chirpoy 21 691 46°30" 150°55"
Brat-Chirpoev 16 749 46°28" 150°50"

Southern group
Urup 1450 1426 45°54" 149°59"
Iturup 3318.8 1634 45°00" 147°53"
Kunashir 1495.24 1819 44°05" 145°59"

Small Kuril ridge
Shikotan 264.13 412 43°48" 146°45"
Polonsky 11.57 16 43°38" 146°19"
Green 58.72 24 43°30" 146°08"
Tanfilyeva 12.92 15 43°26" 145°55"
Yuri 10.32 44 43°25" 146°04"
Anuchina 2.35 33 43°22" 146°00"

Geological structure
The Kuril Islands are a typical ensimatic island arc on the edge of the Okhotsk plate. It lies above a subduction zone in which the Pacific plate is being absorbed. Most of the islands are mountainous. The highest altitude is 2339 m - Atlasov Island, Alaid Volcano. The Kuril Islands are located in the Pacific volcanic ring of fire in a zone of high seismic activity: out of 68 volcanoes, 36 are active, and there are hot mineral springs. Large tsunamis are common. The best known are the tsunami of November 5, 1952 at Paramushir and the Shikotan tsunami of October 5, 1994. The last major tsunami occurred on November 15, 2006 in Simushir.

DETAILED GEOGRAPHY OF THE SEA OF OKHOTSK, DESCRIPTION OF THE SEA
Main physical and geographical features.
The straits connecting the Sea of ​​Okhotsk with the Pacific Ocean and the Sea of ​​Japan, and their depths, are very important, as they determine the possibility of water exchange. The Nevelskoy and La Perouse straits are relatively narrow and shallow. The width of the Nevelskoy Strait (between capes Lazarev and Pogibi) is only about 7 km. The width of the La Perouse Strait is slightly larger - about 40 km, and the greatest depth is 53 m.

At the same time, the total width of the Kuril Straits is about 500 km, and the maximum depth of the deepest of them (Bussol Strait) exceeds 2300 m. Thus, the possibility of water exchange between the Sea of ​​Japan and the Sea of ​​Okhotsk is incomparably less than between the Sea of ​​Okhotsk and the Pacific Ocean. However, even the depth of the deepest of the Kuril Straits is significantly less than the maximum depth of the sea, therefore g, fencing off the sea depression from the ocean.
The most important for water exchange with the ocean are the Bussol and Krusenstern straits, since they have the largest area and depth. The depth of the Bussol Strait was indicated above, and the depth of the Kruzenshtern Strait is 1920 m. Of less importance are the Frieza, Fourth Kurilsky, Rikord and Nadezhda straits, whose depths are more than 500 m. The depths of the remaining straits generally do not exceed 200 m, and the areas are insignificant.

The shores of the Sea of ​​Okhotsk, which are different in external shape and structure in different areas, belong to different geomorphological types. From Fig. 38 it is clear that for the most part these are abrasive shores modified by the sea; only in the west of Kamchatka and in the east of Sakhalin are there accumulative shores. The sea is mostly surrounded by high and steep shores. In the north and northwest, rocky ledges descend directly to the sea. A less high, and then low, continental coast approaches the sea near Sakhalin Bay. The southeastern coast of Sakhalin is low, and the northeastern coast is low. very steep. The northeastern coast of Hokkaido is predominantly low-lying. The coast of the southern part of western Kamchatka has the same character, but its northern part is distinguished by some elevation of the coast.

The bottom topography of the Sea of ​​Okhotsk is varied and uneven. In general, it is characterized by the following main features. The northern part of the sea is a continental shelf - an underwater continuation of the Asian continent. The width of the continental shelf in the area of ​​the Ayano-Okhotsk coast is approximately 100 miles, in the area of ​​Udskaya Bay - 140 miles. Between the meridians of Okhotsk and Magadan its width increases to 200 miles. On the western edge of the sea basin there is the island sandbank of Sakhalin, on the eastern edge there is the mainland sandbank of Kamchatka. The shelf occupies about 22% of the bottom area. The rest, most (about 70%) of the sea is located within the continental slope (from 200 to 1500 m), on which individual underwater hills, depressions and trenches are distinguished.
The deepest southern part of the sea, deeper than 2500 m, representing the bed area, occupies 8% of the total area. It stretches as a strip along the Kuril Islands, gradually narrowing from 200 km against the island. Iturup up to 80 km against the Krusenstern Strait. Great depths and significant bottom slopes distinguish the southwestern part of the sea from the northeastern part, which lies on the continental shallows.
Of the large elements of the bottom relief of the central part of the sea, two underwater hills stand out - the Academy of Sciences of the USSR and the Institute of Oceanology. Together with the protrusion of the continental slope, they determine the division of the sea basin into three basins: the northeastern TINRO depression, the northwestern Deryugin depression and the southern deep-sea Kuril Basin. The depressions are connected by gutters: Makarov, P. Schmidt and Lebed. To the northeast of the TINRO depression, the Shelikhov Bay trench extends.

Kamchatka, race on the shores of the Sea of ​​Okhotsk, Berengia 2013

The deepest TINRO depression is located west of Kamchatka. Its bottom is a plain lying at a depth of about 850 m with a maximum depth of 990 m. The Deryugin Depression is located east of the underwater base of Sakhalin. Its bottom is a flat plain, raised at the edges, lying on average at a depth of 1700 m, the maximum depth of the depression is 1744 m. The deepest is the Kuril Basin. This is a huge flat plain lying at a depth of about 3300 m. Its width in the western part is about 120 miles, and its length in a northeast direction is about 600 miles.

The hill of the Institute of Oceanology has a rounded outline; it is elongated in the latitudinal direction for almost 200 miles, and in the meridional direction for about 130 miles. The minimum depth above it is about 900 m. The heights of the USSR Academy of Sciences are cut by the tops of underwater valleys. A remarkable feature of the topography of the hills is the presence of flat peaks that occupy a large area.

CLIMATE OF THE SEA OF OKHOTSK
By its location, the Sea of ​​Okhotsk is located in the monsoon climate zone of temperate latitudes, which is significantly influenced by the physical and geographical features of the sea. Thus, a significant part of it in the west extends deep into the mainland and lies relatively close to the cold pole of the Asian landmass, so the main source of cold for the Sea of ​​Okhotsk is in the west, and not in the north. The relatively high ridges of Kamchatka make it difficult for warm Pacific air to penetrate. Only in the southeast and south is the sea open to the Pacific Ocean and the Sea of ​​Japan, from where a significant amount of heat enters it. However, the influence of cooling factors is stronger than warming ones, so the Sea of ​​Okhotsk as a whole is the coldest of the Far Eastern seas. At the same time, its large meridional extent causes significant spatial differences in synoptic conditions and meteorological indicators in each season. In the cold part of the year, from October to April, the sea is affected by the Siberian Anticyclone and the Aleutian Low. The influence of the latter extends mainly to the southeastern part of the sea. This distribution of large-scale pressure systems determines the dominance of strong, stable northwestern and northern winds, often reaching storm force. Little wind and calm are almost completely absent, especially in January and February. In winter, wind speed is usually 10-11 m/s.

The dry and cold Asian winter monsoon significantly cools the air over the northern and northwestern regions of the sea. In the coldest month (January), the average air temperature in the northwest of the sea is −20–25°, in the central regions −10–15°, only in the southeastern part of the sea it is −5–6°, which is explained by the warming influence Pacific Ocean.

The autumn-winter season is characterized by the occurrence of cyclones of predominantly continental origin. They entail stronger winds and sometimes a drop in air temperature, but the weather remains clear and dry, as they bring in continental air from the cooled mainland of Asia. In March - April, a restructuring of large-scale pressure fields occurs. The Siberian anticyclone is collapsing, and the Honolulu high is intensifying. As a result, during the warm season (from May to October), the Sea of ​​Okhotsk is influenced by the Honolulu High and the low pressure area located over Eastern Siberia. In accordance with this distribution of centers of atmospheric action, weak southeast winds prevail over the sea at this time. Their speed usually does not exceed 6-7 m/s. These winds are most common in June and July, although stronger northwest and northerly winds are sometimes observed during these months. In general, the Pacific (summer) monsoon is weaker than the Asian (winter) monsoon, since in the warm season the horizontal pressure gradients are small.

Nagaevo Bay

In summer, the air warms up unevenly over the entire sea. The average monthly air temperature in August decreases from southwest to northeast from 18° in the south, to 12–14° in the center and to 10–10.5° in the northeast of the Sea of ​​Okhotsk. In the warm season, oceanic cyclones often pass over the southern part of the sea, which is associated with increased winds to storm winds, which can last up to 5-8 days. The predominance of south-eastern winds in the spring-summer season leads to significant cloudiness, precipitation, and fog. Monsoon winds and stronger winter cooling of the western part of the Sea of ​​Okhotsk compared to the eastern part are important climatic features of this sea.
Quite a lot of mostly small rivers flow into the Sea of ​​Okhotsk, therefore, with such a significant volume of its waters, the continental flow is relatively small. It is approximately 600 km3/year, with about 65% coming from the Amur. Other relatively large rivers - Penzhina, Okhota, Uda, Bolshaya (in Kamchatka) - bring significantly less fresh water to the sea. It arrives mainly in spring and early summer. At this time, the influence of continental runoff is most noticeable, mainly in the coastal zone, near the mouths of large rivers.

Geographical location, large meridian length, monsoon wind changes and good connection between the sea and the Pacific Ocean through the Kuril Straits are the main natural factors that most significantly influence the formation of the hydrological conditions of the Sea of ​​Okhotsk. The amounts of heat inflow and outflow into the sea are determined mainly by radiation heating and cooling of the sea. The heat brought by Pacific waters is of subordinate importance. However, for the water balance of the sea, the arrival and flow of water through the Kuril Straits plays a decisive role. The details and quantitative indicators of water exchange through the Kuril Straits have not yet been sufficiently studied, however, the main routes of water exchange through the straits are known. The flow of surface Pacific waters into the Sea of ​​Okhotsk occurs mainly through the northern straits, in particular through the First Kuril Strait. In the straits of the middle part of the ridge, both the influx of Pacific waters and the outflow of Okhotsk waters are observed. Thus, in the surface layers of the Third and Fourth Kuril Straits, apparently, there is a drainage of water from the Sea of ​​Okhotsk, while in the bottom layers there is an influx, and in the Bussol Strait, on the contrary: in the surface layers there is an influx, in the deep layers there is a runoff. In the southern part of the ridge, mainly through the Ekaterina and Frieze straits, water predominantly drains from the Sea of ​​Okhotsk. The intensity of water exchange through the straits can vary significantly. In general, in the upper layers of the southern part of the Kuril ridge, the flow of Sea of ​​Okhotsk waters predominates, and in the upper layers of the northern part of the ridge, the influx of Pacific waters occurs. In the deep layers, the influx of Pacific waters generally predominates.
The influx of Pacific waters largely affects the distribution of temperature, salinity, formation of the structure and general circulation of the waters of the Sea of ​​​​Okhotsk.

Cape Stolbchaty, Kunashir Island, Kuril Islands

Hydrological characteristics.
Sea surface water temperatures generally decrease from south to north. In winter, almost everywhere the surface layers are cooled to a freezing temperature of −1.5–1.8°. Only in the southeastern part of the sea does it remain around 0°, and near the northern Kuril Straits, the water temperature under the influence of Pacific waters penetrating here reaches 1-2°.

Spring warming at the beginning of the season mainly leads to the melting of ice, only towards the end of it does the water temperature begin to rise. In summer, the distribution of water temperature on the sea surface is quite varied (Fig. 39). In August, the waters adjacent to the island are the warmest (up to 18-19°). Hokkaido. In the central regions of the sea, the water temperature is 11-12°. The coldest surface waters are observed near the island. Iona, near Cape Pyagin and near the Krusenstern Strait. In these areas, the water temperature is between 6-7°. The formation of local centers of increased and decreased water temperatures on the surface is mainly associated with the redistribution of heat by currents.

The vertical distribution of water temperature varies from season to season and from place to place. In the cold season, temperature changes with depth are less complex and varied than in warm seasons. In winter, in the northern and central regions of the sea, water cooling extends to horizons of 100–200 m. The water temperature is relatively uniform and drops from −1.7–1.5° on the surface to −0.25° at horizons of 500–600 m, deeper rises to 1-2° in the southern part of the sea, near the Kuril Straits the water temperature from 2.5-3.0° on the surface drops to 1.0-1.4° at horizons of 300-400 m and then gradually rises to 1, 9-2.4° at the bottom.

In summer, surface waters are heated to a temperature of 10-12°. In the subsurface layers, the water temperature is slightly lower than on the surface. A sharp decrease in temperature to values ​​of −1.0–1.2° is observed between horizons of 50–75 m; deeper to horizons of 150–200 m the temperature rises to 0.5–1.0°, and then its increase occurs more smoothly and at at horizons of 200–250 m it is 1.5–2.0°. From here the water temperature remains almost unchanged to the bottom. In the southern and southeastern parts of the sea, along the Kuril Islands, the water temperature from 10-14° on the surface drops to 3-8° at a horizon of 25 m, then to 1.6-2.4° at a horizon of 100 m and to 1 .4-2.0° at the bottom. The vertical distribution of temperature in summer is characterized by a cold intermediate layer - a remnant of the winter cooling of the sea (see Fig. 39). In the northern and central regions of the sea, the temperature is negative and only near the Kuril Straits it has positive values. In different areas of the sea, the depth of the cold intermediate layer is different and varies from year to year.

The distribution of salinity in the Sea of ​​Okhotsk changes relatively little over the seasons and is characterized by its increase in the eastern part, which is under the influence of Pacific waters, and its decrease in the western part, desalinated by continental runoff (Fig. 40). In the western part, the salinity on the surface is 28–31‰, and in the eastern part it is 31–32‰ and more (up to 33‰ near the Kuril ridge). In the northwestern part of the sea, due to desalination, the salinity on the surface is 25‰ or less, and the thickness of the desalinated layer is about 30-40 m.
Salinity increases with depth in the Sea of ​​Okhotsk. At horizons of 300–400 m in the western part of the sea, salinity is 33.5‰, and in the eastern part it is about 33.8‰. At a horizon of 100 m, salinity is 34.0‰ and further towards the bottom it increases slightly - by only 0.5-0.6‰. In individual bays and straits, the value of salinity and its stratification may differ significantly from the open sea, depending on local hydrological conditions.

Temperature and salinity determine the magnitude and density distribution of the waters of the Sea of ​​Okhotsk. Accordingly, denser waters are observed in winter in the northern and central ice-covered areas of the sea. The density is somewhat lower in the relatively warm Kuril region. In summer, the density of water decreases, its lowest values ​​are confined to zones of influence of coastal runoff, and the highest are observed in areas of distribution of Pacific waters. Density increases with depth. In winter, it rises relatively slightly from the surface to the bottom. In summer, its distribution depends in the upper layers on temperature values, and in the middle and lower horizons on salinity. In summer, a noticeable density stratification of waters is created vertically, the density increases especially significantly at horizons of 25-35-50 m, which is associated with the heating of waters in open areas and desalination near the coast.

Cape Nyuklya (sleeping Dragon) near Magadan

The possibilities for the development of mixing of waters in the Sea of ​​Okhotsk are largely related to the peculiarities of the vertical distribution of oceanological characteristics. Wind mixing occurs during the ice-free season. It occurs most intensely in spring and autumn, when strong winds blow over the sea, and the stratification of waters is not yet very pronounced. At this time, wind mixing extends to a horizon of 20-25 m from the surface. Strong cooling and powerful ice formation in autumn-winter contribute to the development of convection in the Sea of ​​Okhotsk. However, it flows differently in its different areas, which is explained by the peculiarities of the bottom topography, climatic differences, the flow of Pacific waters and other factors. Thermal convection in most of the sea penetrates up to 50-60 m, since the summer heating of surface waters, and in zones influenced by coastal runoff and significant desalination, cause vertical stratification of water, which is most pronounced at these horizons. The increase in the density of surface waters due to cooling and the resulting convection are not able to overcome the maximum stability located at the mentioned horizons. In the southeastern part of the sea, where Pacific waters predominantly spread, a relatively weak vertical stratification is observed, so thermal convection extends here to horizons of 150-200 m, where it is limited by the density structure of the waters.
Intense ice formation over most of the sea stimulates enhanced thermohaline winter vertical circulation. At depths of up to 250-300 m, it spreads to the bottom, and its penetration to greater depths is prevented by the maximum stability that exists here. In areas with rugged bottom topography, the spread of density mixing into the lower horizons is facilitated by the sliding of water along the slopes. In general, the Sea of ​​Okhotsk is characterized by good mixing of its waters.

Features of the vertical distribution of oceanological characteristics, mainly water temperature, indicate that the Sea of ​​Okhotsk is characterized by a subarctic structure of waters, in which cold and warm intermediate layers are well defined in summer. A more detailed study of the subarctic structure in this sea showed that there are Sea of ​​Okhotsk, Pacific and Kuril varieties of the subarctic water structure. Although they have the same vertical structure, they have quantitative differences in the characteristics of water masses.

Based on the analysis of T and S-curves in combination with consideration of the vertical distribution of oceanological characteristics in the Sea of ​​Okhotsk, the following water masses are distinguished. Surface water mass that has spring, summer and autumn modifications. It represents the upper maximum of stability, determined mainly by temperature. This water mass is characterized by temperature and salinity values ​​corresponding to each season, on the basis of which its mentioned modifications are distinguished.
The Sea of ​​Okhotsk water mass is formed in winter from surface water and in spring, summer and autumn appears in the form of a cold intermediate layer, flying between horizons of 40-150 m. This water mass is characterized by a fairly uniform salinity (about 32.9-31.0‰) and varying from place to place temperature. In most of the sea, its temperature is below 0° and reaches −1.7°, and in the area of ​​the Kuril Straits it is above 1°.

The intermediate water mass is formed mainly due to the sinking of water along the slopes of the bottom; within the sea it is located from 100–150 to 400–700 m and is characterized by a temperature of 1.5° and a salinity of 33.7‰. This water mass is distributed almost everywhere, except for the northwestern part of the sea, Shelikhov Bay and some areas along the coast of Sakhalin, where the Sea of ​​Okhotsk water mass reaches the bottom. The thickness of the intermediate water mass layer generally decreases from south to north.

The deep Pacific water mass is the water of the lower part of the warm layer of the Pacific Ocean, entering the Sea of ​​Okhotsk at horizons below 800-2000 m, i.e. below the depth of the waters descending in the straits, and appears in the sea as a warm intermediate layer. This water mass is located at horizons of 600–1350 m, has a temperature of 2.3° and a salinity of 34.3‰. However, its characteristics change in space. The highest values ​​of temperature and salinity are observed in the northeastern and partly in the northwestern regions, which is associated here with rising waters, and the lowest values ​​of the characteristics are characteristic of the western and southern regions, where subsidence of waters occurs.
The water mass of the Southern Basin is of Pacific origin and represents deep water of the northwestern part of the Pacific Ocean from a horizon of 2300 m, corresponding to the maximum depth of the threshold in the Kuril Straits (Bussol Strait). The water mass in question generally fills the named basin from a horizon of 1350 m to the bottom. It is characterized by a temperature of 1.85° and a salinity of 34.7‰, which vary only slightly with depth.
Among the identified water masses, the Sea of ​​Okhotsk and the deep Pacific are the main ones and differ from each other not only in thermohaline, but also in hydrochemical and biological parameters.

Under the influence of winds and the influx of water through the Kuril Straits, the characteristic features of the system of non-periodic currents of the Sea of ​​Okhotsk are formed (Fig. 41). The main one is a cyclonic system of currents that covers almost the entire sea. It is caused by the predominance of cyclonic circulation of the atmosphere over the sea and the adjacent part of the Pacific Ocean. In addition, stable anticyclonic gyres and vast areas of cyclonic water circulation can be traced in the sea.

At the same time, a narrow strip of stronger coastal currents stands out quite clearly, which, continuing each other, seem to go around the sea coastline counterclockwise; warm Kamchatka Current directed north to Shelikhov Bay; flow of a western and then southwestern direction along the northern and northwestern shores of the sea; the stable East Sakhalin Current going south, and the rather strong Soya Current entering the Sea of ​​Okhotsk through the La Perouse Strait.
On the southeastern periphery of the cyclonic circulation of the Central part of the sea, a branch of the Northeast Current is distinguished, opposite in direction to the Kuril Current (or Oyashio) in the Pacific Ocean. As a result of the existence of these flows, stable areas of convergence of currents are formed in some of the Kuril straits, which leads to lowering of waters and has a significant impact on the distribution of oceanological characteristics not only in the straits, but also in the sea itself. And finally, another feature of the circulation of the waters of the Sea of ​​​​Okhotsk is two-way stable currents in most of the Kuril Straits.

Non-periodic currents on the surface of the Sea of ​​Okhotsk are most intense off the western coast of Kamchatka (11-20 cm/s), in the Sakhalin Gulf (30-45 cm/s), in the Kuril Straits area (15-40 cm/s), over the Southern Basin ( 11-20 cm/s) and during the Soya (up to 50-90 cm/s). In the central part of the cyclonic region, the intensity of horizontal transport is much less than at its periphery. In the central part of the sea, velocities vary from 2 to 10 cm/s, with the predominant velocities being less than 5 cm/s. A similar picture is observed in Shelikhov Bay, rather strong currents off the coast (up to 20-30 cm/s) and low speeds in the central part of the cyclonic gyre.

Periodic (tidal) currents are also well expressed in the Sea of ​​Okhotsk. Here their various types are observed: semidiurnal, diurnal and mixed with a predominance of semidiurnal or diurnal components. The speeds of tidal currents vary - from a few centimeters to 4 m/s. Far from the coast, current speeds are low (5-10 cm/s). In straits, bays and off the coast, the speeds of tidal currents increase significantly, for example in the Kuril Straits they reach 2-4 m/s.
The tides of the Sea of ​​Okhotsk are very complex. The tidal wave enters from the south and southeast from the Pacific Ocean. The semidiurnal wave moves north, and at the 50° parallel it divides into two branches: the western one turns to the northwest, forming amphidromic areas north of Cape Terpeniya and in the northern part of Sakhalin Bay, the eastern one moves towards Shelikhov Bay, at the entrance to which it appears another amphidromy. The daily wave also moves north, but at the latitude of the northern tip of Sakhalin it is divided into two parts: one enters Shelikhov Bay, the other reaches the northwestern coast.

There are two main types of tides in the Sea of ​​Okhotsk: daily and mixed. The most common are diurnal tides. They are observed in the Amur Estuary, Sakhalin Bay, on the Kuril Islands, off the western coast of Kamchatka and in the Gulf of Penzhin. Mixed tides are observed on the northern and northwestern coasts of the sea and in the area of ​​the Shantar Islands.
The highest tides were recorded in Penzhinskaya Bay near Astronomichesky Cape (up to 13 m). These are the highest tides for the entire coast of the USSR. In second place is the area of ​​the Shantar Islands, where the tide exceeds 7 m. The tides in the Sakhalin Bay and the Kuril Straits are very significant. In the northern part of the sea, the tides reach up to 5 m. The lowest tides were observed off the eastern coast of Sakhalin, in the area of ​​the La Perouse Strait. In the southern part of the sea, the tide ranges from 0.8 to 2.5 m. In general, tidal fluctuations in the level in the Sea of ​​Okhotsk are very significant and have a significant impact on its hydrological regime, especially in the coastal zone.
In addition to tidal fluctuations, surge level fluctuations are also well developed here. They occur mainly when deep cyclones pass over the sea. Surge increases in level reach 1.5-2 m. The largest surges are noted on the coast of Kamchatka and in Terpeniya Bay.

The considerable size and great depths of the Sea of ​​Okhotsk, frequent and strong winds above it determine the development of large waves here. The sea is especially rough in the fall, and in ice-free areas even in winter. These seasons account for 55-70% of storm waves, including those with wave heights of 4-6 m, and the highest wave heights reach 10-11 m. The most turbulent are the southern and south-eastern regions of the sea, where the average frequency of storm waves is 35 -50%, and in the northwestern part it decreases to 25-30%. With strong waves, a crowd forms in the straits between the Kuril Islands and between the Shantar Islands.

Severe and long winters with strong northwest winds contribute to the development of intense ice formation in the Sea of ​​Okhotsk. The ice of the Sea of ​​Okhotsk is exclusively local in origin. Here there are both fixed ice (fast ice) and floating ice, which represents the main form of sea ice. Ice is found in varying quantities in all areas of the sea, but in summer the entire sea is cleared of ice. The exception is the area of ​​the Shantar Islands, where ice can persist in the summer.
Ice formation begins in November in the bays and lips of the northern part of the sea, in the coastal part of the island. Sakhalin and Kamchatka. Then ice appears in the open part of the sea. In January and February, ice covers the entire northern and middle part of the sea. In normal years, the southern border of the relatively stable ice cover runs, curving north, from the La Perouse Strait to Cape Lopatka. The extreme southern part of the sea never freezes. However, thanks to the winds, significant masses of ice are carried into it from the north, often accumulating near the Kuril Islands.

From April to June, destruction and gradual disappearance of the ice cover occurs. On average, sea ice disappears at the end of May - beginning of June. The northwestern part of the sea, due to currents and the configuration of the shores, is most clogged with ice, which remains there until July. Consequently, the ice cover in the Sea of ​​Okhotsk remains for 6-7 months. Floating ice covers more than three quarters of the sea surface. The compact ice of the northern part of the sea poses a serious obstacle to navigation even for icebreakers. The total duration of the ice period in the northern part of the sea reaches 280 days a year.

The southern coast of Kamchatka and the Kuril Islands belong to areas with little ice cover; here the ice lasts on average no more than three months a year. The thickness of the ice that grows during the winter reaches 0.8–1.0 m. Strong storms and tidal currents break up the ice cover in many areas of the sea, forming hummocks and large open waters. In the open part of the sea, continuous, motionless ice is never observed; here the ice usually drifts in the form of vast fields with numerous leads. Some of the ice from the Sea of ​​Okhotsk is carried into the ocean, where it almost immediately collapses and melts. In severe winters, floating ice is pressed against the Kuril Islands by northwestern winds and clogs some straits. Thus, in winter there is no place in the Sea of ​​Okhotsk where encountering ice is completely excluded.

Hydrochemical conditions.
Due to constant water exchange with the Pacific Ocean through the deep Kuril Straits, the chemical composition of the waters of the Sea of ​​Okhotsk is generally no different from the ocean. The values ​​and distribution of dissolved gases and nutrients in open areas of the sea are determined by the influx of Pacific waters, and in the coastal part, coastal runoff has a certain influence.

The Sea of ​​Okhotsk is rich in oxygen, but its content is not the same in different areas of the sea and changes with depth. A large amount of oxygen is dissolved in the waters of the northern and central parts of the sea, which is explained by the abundance of oxygen-producing phytoplankton here. In particular, in the central part of the sea, the development of plant organisms is associated with the rise of deep waters in zones of convergence of currents. The waters of the southern regions of the sea contain less oxygen, since the Pacific waters that are relatively poor in phytoplankton flow here. The highest content (7-9 ml/l) of oxygen is observed in the surface layer; deeper it gradually decreases and at a horizon of 100 m it is 6-7 ml/l, and at a horizon of 500 m it is 3.2-4.7 ml/l. then the amount of this gas decreases very quickly with depth and reaches a minimum at horizons of 1000–1300 m (1.2–1.4 ml/l), but in deeper layers it increases to 1.3–2.0 ml/l. The oxygen minimum is confined to the deep Pacific water mass.

The surface layer of the sea contains 2-3 µg/l of nitrites and 3-15 µg/l of nitrates. With depth, their concentration increases, and the content of nitrites reaches a maximum at horizons of 25-50 m, and the amount of nitrates here increases sharply, but the greatest values ​​of these substances are noted at horizons of 800-1000 m, from where they slowly decrease towards the bottom. The vertical distribution of phosphates is characterized by an increase in their content with depth, especially noticeable from horizons of 50-60 m, and the maximum concentration of these substances is observed in the bottom layers. In general, the amount of nitrites, nitrates and phosphates dissolved in sea waters increases from north to south, which is mainly due to the rise of deep waters. Local features of hydrological and biological conditions (water circulation, tides, degree of development of organisms, etc.) form the regional hydrochemical features of the Sea of ​​Okhotsk.

Economic use.
The economic importance of the Sea of ​​Okhotsk is determined by the use of its natural resources and maritime transport. The main wealth of this sea is game animals, primarily fish. Here, mainly its most valuable species are caught - salmon (chum salmon, pink salmon, sockeye salmon, coho salmon, chinook salmon) and their caviar. Currently, salmon stocks have decreased, and therefore their production has decreased. Fishing for this fish is limited. In addition, herring, cod, flounder and other types of marine fish are caught in the sea in limited quantities. The Sea of ​​Okhotsk is the main crab fishing area. Squid are being harvested in the sea. One of the largest herds of fur seals is concentrated on the Shantar Islands, the hunting of which is strictly regulated.

Sea transport lines connect the Okhotsk ports of Magadan, Nagaevo, Ayan, Okhotsk with other Soviet and foreign ports. Various cargoes arrive here from different regions of the Soviet Union and foreign countries.

The largely studied Sea of ​​Okhotsk still needs to solve various natural problems. In terms of their hydrological aspects, studies of water exchange between the sea and the Pacific Ocean, general circulation, including vertical movements of water, their fine structure and eddy-like movements, ice conditions, especially in the prognostic direction of the timing of ice formation, the direction of ice drift, etc., occupy an essential place. The solution to these and other problems will contribute to the further development of the Sea of ​​Okhotsk.

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SOURCE OF INFORMATION AND PHOTO:
Team Nomads
http://tapemark.narod.ru/more/18.html
Melnikov A.V. Geographical names of the Russian Far East: Toponymic Dictionary. — Blagoveshchensk: Interra-Plus (Interra+), 2009. — 55 p.
Shamraev Yu. I., Shishkina L. A. Oceanology. L.: Gidrometeoizdat, 1980.
Lithosphere of the Sea of ​​Okhotsk
The Sea of ​​Okhotsk in the book: A. D. Dobrovolsky, B. S. Zalogin. Seas of the USSR. Publishing house Moscow. University, 1982.
Leontyev V.V., Novikova K.A. Toponymic dictionary of the north-east of the USSR. - Magadan: Magadan Book Publishing House, 1989, page 86
Leonov A.K. Regional oceanography. - Leningrad, Gidrometeoizdat, 1960. - T. 1. - P. 164.
Wikipedia website.
Magidovich I. P., Magidovich V. I. Essays on the history of geographical discoveries. - Enlightenment, 1985. - T. 4.
http://www.photosight.ru/
photo: O. Smoliy, A. Afanasyev, A. Gill, L. Golubtsova, A. Panfilov, T. Selena.

The Sea of ​​Okhotsk on the modern map of Russia is of great economic and environmental importance. Due to the difficult political situation in relations with Japan, the importance of the sea for ensuring the security of the borders of the Russian Federation is also increasing.

The Sea of ​​Okhotsk on the map of Russia is an inland reservoir of the Pacific Basin deeply embedded in the mainland, framed by the shores of the Asian continent, the Kamchatka Peninsula, the islands of Hokkaido, Sakhalin and the Kuril Islands.

History of the study

Russian explorers V.D. Poyarkov and I.Yu. Moskvitin, who explored the lands of the Far East with Cossack squads, in the middle of the 17th century described the new sea they discovered.

The study of climatic features, river hydrography, nature, lifestyle of the local population, wildlife and coastal mapping were carried out in the period from 1733 to 1743 during a research expedition led by Vitus Bering.

In 1805, a description of the eastern coast of the island. Sakhalin was made by an expedition team led by I.F. Kruzenshtern, who made a trip around the world with the crew of the Nadezhda ship.

In the period from 1849 to 1855, an expedition led by G.I. Nevelskoy explored the shores in the southwest of the Sea of ​​Okhotsk, the place where the river flows into the strait. Amur and determined that Sakhalin is an island. Convenient harbors and bays for mooring ships were marked on geographical maps, and the natural resources of the lower reaches of the river were described. Amur, Ussuri region and about. Sakhalin, where coal reserves have been discovered.

1894 was marked by the compilation of the first complete summary of the hydrology of the sea by naval commander and admiral S.O. Makarov, who analyzed numerous ocean water samples taken by many ships, including in the Sea of ​​Okhotsk.

In Soviet times and in the modern history of Russia, research expeditions were carried out for many years with the involvement of special scientific vessels and scientists, including the Far Eastern Branch of the Russian Academy of Sciences, to study the hydrography, weather and resources of the Sea of ​​​​Okhotsk.

Characteristics of the sea: salt level, area, depth

The total area of ​​the water sea surface is 1 million 600 thousand km 2, on average the depth of the reservoir is about 820 m, the deepest place is more than 3900 m. The shelf in the western part is shallow, in the center there are significant depressions Deryugin and TINRO, on in the east there is a narrow basin with considerable depth along the Kuril Islands.

The salinity values ​​of sea water are different:

• near the coast - less than 30% (the influence of the flow of numerous rivers);
• on the surface – up to 33.8%;
• intermediate layers - 34.5% (infusion of a significant mass of salty ocean waters with the help of deep currents);
• at great depths - up to 33.4%.

Water temperature by month

Sea water temperatures vary depending on the water layer and the currents or local river flows that affect them.
The average temperatures of the surface sea layer are given in the table (top line – months; lower – average temperature value, o C):

1	2	3	4	5	6	7	8	9	10	11	12
+2,4	+0,3	-0,4	0	+1,3	+2,1	+5,3	+6	+10	+8,1	+4,5	+3

Resources

The natural resources of the Sea of ​​Okhotsk basin are currently significantly depleted as a result of poaching in the 90s of the last century. This has led these days to the introduction of restrictions on the catch of certain types of fish and the catch of fur seals.

The region has significant proven reserves of coal, oil, gas, nickel, silver and gold. There are placers of beautiful Kamchatka amber.

Flora and fauna of the Sea of ​​Okhotsk

Representatives of the fauna of the northern strip and Arctic representatives live on the harsh shores of the Sea of ​​​​Okhotsk:

• wolves;
• foxes;
• wolverines;
• the Bears;
• white partridges.

In the depths of the sea live:

In addition to fish resources, the following are found in sea waters:

• sea ​​urchins;
• sea ​​stars;
• mussels;
• shrimps;
• jellyfish;
• crabs.

The bird world is represented by numerous colonies:

• seagulls;
• petrels;
• cormorants;
• geese;
• guillemots.

Seaweeds harvested and used for food:

• red, brown and green;
• kelp;
• sea ​​grass - zoster.

Which cities are washed by the Sea of ​​Okhotsk?

The following cities and large settlements operate directly next to the Sea of ​​Okhotsk:

Name	Population (thousand people)	Main occupation of residents
Magadan	more than 92.7	mechanical engineering, helicopter repair, mining equipment production, fish processing, timber processing, coal shipment, gold mining, seaport
Korsakov (Aniva Bay, Sakhalin Island)	about 33.2	seafood production and processing, gas processing plant, seaport
Kholmsk	about 28	ship repair, seafood production and processing, woodworking, tourism, sea ​​port
Poronaysk (Terpeniya Bay, Sakhalin Island)	about 15.3	electricity generation, fish production and processing, construction materials production, seaport
Yuzhno-Kurilsk	more than 7.7	fish production and processing, geothermal power plant, gold exploration and mining, sea ​​port
Okhotsk	more than 3.3	mining and processing of gold and silver, industrial fishing and processing, seaport
Kurilsk (Iturup Island)	more than 1.6	seafood production and processing, seaport
Evensk	about 1.5	reindeer husbandry, fishing, berry picking
Chumikan (Udskaya lip)	about 1	artel mining of gold, fishing and processing of fish, game hunting
Ayan	less than 0.9	local crafts

The importance of the Sea of ​​Okhotsk for Russia

The Sea of ​​Okhotsk occupies an important place on the map of Russia, showing fishing grounds for fish and seafood in the Far East. A large number of different species of salmon fish, several varieties of crabs and shrimp, whales, fur seals, seals, and sea lions make up the food potential of this region and the strategic reserve of Russia.

Marine shipping routes are important for ensuring the livelihoods of coastal settlements and other territories of the Far Eastern Territory.

A large volume of cargo consumed by adjacent regions and exported is handled by the ports of Magadan, Korsakov, Okhotsk, Poronaysk, and Yuzhno-Kurilsk.

Development of transport infrastructure, strengthening of border lines, modernization of outposts located on the islands of the Kuril chain and about. Sakhalin has been one of the priority areas in Russian policy in recent years. This is due to the growing threat from US military bases located in Japan.

Economic use

The Sea of ​​Okhotsk is on the map an economic and trade zone of 2 countries - Russia and Japan, which it washes.

They carry out commercial fishing in sea waters for many species of fish and shellfish:

• salmon;
• sockeye salmon;
• pink salmon;
• coho salmon;
• navaga;
• pollock;
• cod;
• herring;
• capelin;
• shrimp;
• crabs

Hydrocarbon deposits have been explored on the Sakhalin, West Kamchatka and Magadan shelves, which are produced on drilling platforms with the participation of foreign companies.

Transport shipping routes pass through the sea area to the ports of the northern Far East and Kamchatka (Magadan, Okhotsk, Severo-Kurilsk, Korsakov). Navigation is hampered by the presence of large ice fields (freeze-up lasts up to 10 months a year) and prolonged storms (lasting up to 7-10 days with wave heights of up to 10 - 11 m).

Industry

Industrial production in the Sea of ​​Okhotsk basin is focused on ensuring the extraction of marine fish resources: port facilities, ship repair yards, factories for processing caviar, fish and seafood (state and commercial). Fish and seafood processing products are popular not only in Russia, but also abroad.

Oil and gas production enterprises in offshore fields have developed significantly, which in recent years have been combined with processing plants that supply their products to many countries in the Pacific basin (Japan, China, Indonesia, Korea, Vietnam).

The region has developed complexes for processing timber, copper-nickel, silver and gold ores, and the production of building materials is developing.

Bays

The sea, as a result of long-term geological processes, has formed several remarkable bays on the coastline:

• Shelekhova together with Gizhiga Bay (the mouth of the Gizhiga River) and Penzhinskaya Bay (the mouth of the Penzhina River);
• Sakhalinsky;
• Uda Bay (the mouth of the Uda River opposite the Shantar Islands);
• Tauyskaya Bay (confluence of 4 rivers and several small bays);
• Tugursky;
• Aniva;
• Patience;
• Odessa (on Iturup Island).

Straits

When considering its location, the Sea of ​​Okhotsk on the map of Russia draws attention to the presence of more than 30 straits that connect it to the Pacific Ocean.

The most significant of them:

The narrow and shallow straits of Nevelskoy and La Perouse lead to the Sea of ​​Japan past the northern and southern ends of the island. Sakhalin.

Bottom and coastline

About 22% of the seabed is shelf and continental shoals (Kamchatka, Asian, Sakhalin). About 70% are continental slopes, deep depressions and elongated trenches (depth from 200 m to 1500 m). Along a series of different-sized Kuril Islands there is a narrow, deep (more than 2500 m) trench that makes up the remaining 8% of the bottom.

In the middle water area of ​​the sea, two ridges were formed by tectonic forces: the Academy of Sciences and the Institute of Oceanology, which conditionally divide the sea basin into significant natural depressions:

The shoreline of the reservoir is different:

• in the northern coastal zones it is indented by small bays with high cliffs and weathered rocks;
• in the area of ​​the northeastern zones - the high shores of the large Shelekhov Bay with the Penzhinskaya and Gizhiginskaya bays;
• in the east there is an almost flat, without pronounced bays, low coast of the Kamchatka Peninsula;
• in the west there is a low-height rocky coast of the Sakhalin Bay and the Shantar Sea;
• in the south – the gentle bays of Aniva and Terpeniya;
• on o. Iturup - Odessa Bay, high rocky shores of other islands in the ridge.

Water exchange

The Sea of ​​Okhotsk on the map of Russia, when considering water exchange processes and currents, draws the attention of researchers to the small width and depth of the La Perouse and Nevelskoy straits, which does not allow for intensive exchange of water masses with the warmer Sea of ​​Japan.

The large number of straits of the Kuril ridge (their total width is about 500 km) and their relatively large depth (Bussol - more than 2300 m, Kruzenshtern - more than 1900 m) contribute to a more intensive exchange of water masses from the Sea of ​​Okhotsk with the Pacific Ocean.

The straits of the northern Kuril Islands allow surface ocean waters to flow into the Sea of ​​Okhotsk with currents; middle straits work in both directions, pumping water currents at different levels; the southern ones, on the contrary, drain more sea water into the Pacific Ocean.

Ecological problems

The presence of environmental problems in the Sea of ​​Okhotsk basin is associated with human economic activity: the entry into the sea of ​​oil and gas products, industrial and domestic wastewater, pollution from passing ships and fishing trawlers.

The greatest pollution is observed in the waters of the island. Sakhalin and Shelekhov Bay in the area of ​​major seaports. Unfavorable factors contributing to the widespread distribution of dirty waters are natural ebbs and flows.

In addition to sea water pollution, there is an increase in emissions of harmful gases into the air from the combustion of hydrocarbons at production sites and from industrial enterprises of large processing centers in the region; in addition, frequent eruptions of local volcanoes add harmful impurities to the air above the sea.

Interesting facts about the Sea of ​​Okhotsk

The following are considered significant and indisputable facts about the Sea of ​​Okhotsk:

The Sea of ​​Okhotsk occupies a unique place on the map of Russia due to the presence in its waters and on the adjacent shores of significant reserves of various types of resources: mineral, biological and natural. Sea transport is of exceptional importance due to the insignificant development of rail and road transport in the region.

Article format: Mila Friedan

Video about the Sea of ​​Okhotsk

Documentary film “The Golden Bottom of the Sea of ​​Okhotsk”:

The Sea of ​​Okhotsk is a semi-enclosed sea located in the northern hemisphere, part of the Pacific Ocean, washing the shores of Russia and Japan.

Previously, this sea was called “Kamchatka”. The Japanese called this sea "Hokkai", which literally translates as "North Sea", but the traditional name eventually changed to the Sea of ​​Okhotsk.

What rivers flow into

The following large rivers flow into the Sea of ​​Okhotsk:

• Kukhtui (a river whose length reaches 384 kilometers, it is located in the Khabarovsk Territory, just like the Okhota River);
  
• Okhota (a small river in the Khabarovsk Territory, the length of which reaches almost 400 kilometers);
• Amur (the length of the river reaches almost 2900 km, which makes this waterway quite large and important in Eastern Russia and China for infrastructure).

Relief of the Sea of ​​Okhotsk

The western part of the bottom is a flat slab and is located at a fairly shallow depth. In the very center there are large depressions. However, the maximum depth was recorded in the so-called Kuril Basin, which is located in the eastern part of the Sea of ​​Okhotsk. The bottom can be sandy, rocky, muddy-sandy.

The seashores are mostly high and rocky. In the southwest of Kamchatka the shores have low relief. There are volcanoes at the bottom of the Sea of ​​Okhotsk, and there are also on the islands. 70 are considered extinct, 30 are considered active.

The southeastern part of the sea almost never freezes - even in winter, which cannot be said about the northern part of the sea, where ice persists from October to June. The northern coast of the sea is heavily indented, which is why many natural bays have been created here, the largest of which is called Sherikhov Bay. In the west of the sea there are also many bays, the largest of which are the Shantar Sea and Sakhalin Bay.

Cities

On the shores of the Sea of ​​Okhotsk there is a small town called Okhotsk, which became the first Russian settlement built on the shores of the Pacific Ocean. Magadan is considered one of the largest cities on the shores of the Sea of ​​Okhotsk with a population of more than 90 thousand inhabitants.

Kholmsk photo

On the seashore there is also a relatively small town of Kholmsk with a population of 28 thousand inhabitants. Well, the last “big city” on the Sea of ​​Okhotsk can be called Korsakov with a population of 33 thousand people. The city is actively involved in fishing and fish processing.

Flora and fauna of the Sea of ​​Okhotsk

The number of fish species in the Sea of ​​Okhotsk is large; there has always been a fair amount of it, which is why the sea has become an important industrial site. The largest quantities in the Sea of ​​Okhotsk are herring, capelin, salmon, pollock and navaga. Among other valuable seafood, one can also highlight Kamchatka crab - they reach truly enormous sizes and are a delicacy for humans.

Beluga whale in the Sea of ​​Okhotsk photo

Sea urchins, starfish, shrimp and crabs, mussels, jellyfish, and corals live here. The Kamchatka crab is one of the largest representatives of crustaceans in the Far Eastern waters.

As in many northern waters, the Sea of ​​Okhotsk is home to several species of whales, including the rare fin whale, as well as the largest creatures on the planet to ever exist, blue whales. The waters of the sea are inhabited by beluga whales, seals and seals.

depths of the Sea of ​​Okhotsk photo

The world of birds is diverse and numerous. On the islands of the Sea of ​​Okhotsk, large colonies of gulls, cormorants, guillemots, guillemots, mottled guillemots, petrels, geese, etc. nest in large colonies.

birds on the Sea of ​​Okhotsk photo

Sea vegetation: brown and green algae, red algae, kelp, in some places there are abundant thickets of sea grass - zoster.

Characteristics of the Sea of ​​Okhotsk

The area of ​​the Sea of ​​Okhotsk reaches 1,603,000 square kilometers, and its volume exceeds 1,300,000 cubic meters. The average depth of the sea is quite large - approximately 1,700 meters, and the deepest point of the seabed is located at a depth of 3,916 meters.

In summer, the sea surface temperature is 18 degrees Celsius. And in winter it is colder - 2 degrees Celsius, and sometimes it can drop to minus temperatures -1.8 degrees. As for the climate, it is monsoonal, very harsh due to the northern winds, only in the south the air temperature is relatively high.

Sea of ​​Okhotsk in winter photo

If we compare the Sea of ​​Okhotsk with the neighboring seas: the Japanese and Bering seas, then it will be the coldest of them. In winter, the Sea of ​​Okhotsk is tormented by strong northern winds and thereby makes the climate even more severe. The minimum air temperature comes with January and reaches -25 degrees on average. In summer, the temperature rarely exceeds +15 degrees.

Quite often, storms occur on the Sea of ​​Okhotsk that last more than one week. They come to the southern part of the sea from the Pacific Ocean. The waves are high and the storms are long. In very severe winters, ice forms - both floating and also stationary. Ice floes float along Sakhalin and the Amur region, often even in summer.

Sakhalin photo

Coastal waters are the least saline and generally do not reach even 30%. But in the rest of the sea, the salt level sometimes reaches up to 34%. Surface waters are the least saline - no more than 32-33%, while already at depth the salinity exceeds 34%.

There are also islands in the Sea of ​​Okhotsk, but their number is extremely small. The largest one is Sakhalin Island. Most of the islands are located in a seismically active zone.

Main physical and geographical features. In the chain of our Far Eastern seas, it occupies a middle position, protrudes quite deeply into the Asian continent, and is separated from the Pacific Ocean by the arc of the Kuril Islands. The Sea of ​​Okhotsk has natural boundaries almost everywhere and only in the southwest from the Sea of ​​Japan it is separated by conventional lines: Cape Yuzhny - Cape Tyk and in the La Perouse Strait Cape Crillon - Cape Soya. The southeastern border of the sea runs from Cape Nosyappu (Hokkaido Island) through the Kuril Islands to Cape Lopatka (Kamchatka), while all passages between the island. Hokkaido and Kamchatka are included in the Sea of ​​Okhotsk. Within these limits, the sea extends from north to south from 62°42′ to 43°43′ N. w. and from west to east from 134°50′ to 164°45′ E. The sea is significantly extended from southwest to northeast and expanded approximately in its central part (Fig. 1).

Rice. 1. Types of shores and bottom topography of the Sea of ​​Okhotsk. Conditional for designations see

The Sea of ​​Okhotsk is one of the largest and deepest seas in our country. Its area is 1603 thousand km 2, volume 1318 thousand km 3, average depth 821 m, greatest depth 3916 m. According to its geographical location, the predominance of depths up to 500 m and significant spaces occupied by great depths, the Sea of ​​Okhotsk belongs to marginal seas of mixed continental-marginal type.

There are few islands in the Sea of ​​Okhotsk. The largest border island is Sakhalin. The Kuril ridge has about 30 large and many small islands and rocks. The Kuril Islands are located in a belt of seismic activity, which includes more than 30 active and 70 extinct volcanoes. Seismic activity occurs on the islands and underwater. In the latter case, tsunami waves are formed. In addition to the named “marginal” islands in the sea there are the islands of Shantarskie, Spafareva, Zavyalova, Yamskie and the small island of Jonah - the only one of them remote from the coast. Although the coastline is long, it is relatively weakly indented. At the same time, it forms several large bays (Aniva, Terpeniya, Sakhalinsky, Akademii, Tugursky, Ayan, Shelikhova) and bays (Udskaya, Tauyskaya, Gizhiginskaya and Penzhinskaya).

The straits connecting the Sea of ​​Okhotsk with the Pacific Ocean and the Sea of ​​Japan, and their depths, are very important, as they determine the possibility of water exchange. The Nevelskoy and La Perouse straits are relatively narrow and shallow. The width of the Nevelskoy Strait (between capes Lazarev and Pogibi) is only about 7 km. The width of the La Perouse Strait is slightly larger - about 40 km, and the greatest depth is 53 m.

At the same time, the total width of the Kuril Straits is about 500 km, and the maximum depth of the deepest of them (Bussol Strait) exceeds 2300 m. Thus, the possibility of water exchange between the Sea of ​​Japan and the Sea of ​​Okhotsk is incomparably less than between the Sea of ​​Okhotsk and the Pacific Ocean. However, even the depth of the deepest of the Kuril Straits is significantly less than the maximum depth of the sea, so the Kuril ridge is a huge threshold that fences off the sea depression from the ocean.

The most important for water exchange with the ocean are the Bussol and Krusenstern straits, since they have the largest area and depth. The depth of the Bussol Strait was indicated above, and the depth of the Kruzenshtern Strait is 1920 m. Of less importance are the Frieza, Fourth Kurilsky, Rikord and Nadezhda straits, whose depths are more than 500 m. The depths of the remaining straits generally do not exceed 200 m, and the areas are insignificant.

The shores of the Sea of ​​Okhotsk, which are different in external shape and structure in different areas, belong to different geomorphological types. From Fig. 38 it is clear that for the most part these are abrasive shores modified by the sea; only in the west of Kamchatka and in the east of Sakhalin are there accumulative shores. The sea is mostly surrounded by high and steep shores. In the north and northwest, rocky ledges descend directly to the sea. A less high, and then low, continental coast approaches the sea near Sakhalin Bay. The southeastern coast of Sakhalin is low, and the northeastern coast is low. The shores of the Kuril Islands are very steep. The northeastern coast of Hokkaido is predominantly low-lying. The coast of the southern part of western Kamchatka has the same character, but its northern part is distinguished by some elevation of the coast.

The bottom topography of the Sea of ​​Okhotsk is varied and uneven (see Fig. 38). In general, it is characterized by the following main features. The northern part of the sea is a continental shelf - an underwater continuation of the Asian continent. The width of the continental shelf in the area of ​​the Ayano-Okhotsk coast is approximately 100 miles, in the area of ​​Udskaya Bay - 140 miles. Between the meridians of Okhotsk and Magadan its width increases to 200 miles. On the western edge of the sea basin there is the island sandbank of Sakhalin, on the eastern edge there is the mainland sandbank of Kamchatka. The shelf occupies about 22% of the bottom area. The rest, most (about 70%) of the sea is located within the continental slope (from 200 to 1500 m), on which individual underwater hills, depressions and trenches are distinguished.

The deepest southern part of the sea, deeper than 2500 m, representing the bed area, occupies 8% of the total area. It stretches as a strip along the Kuril Islands, gradually narrowing from 200 km against the island. Iturup up to 80 km against the Krusenstern Strait. Great depths and significant bottom slopes distinguish the southwestern part of the sea from the northeastern part, which lies on the continental shallows.

Of the large elements of the bottom relief of the central part of the sea, two underwater hills stand out - the Academy of Sciences of the USSR and the Institute of Oceanology. Together with the protrusion of the continental slope, they determine the division of the sea basin into three basins: the northeastern TINRO depression, the northwestern Deryugin depression and the southern deep-sea Kuril Basin. The depressions are connected by gutters: Makarov, P. Schmidt and Lebed. To the northeast of the TINRO depression, the Shelikhov Bay trench extends.

The deepest TINRO depression is located west of Kamchatka. Its bottom is a plain lying at a depth of about 850 m with a maximum depth of 990 m. The Deryugin Depression is located east of the underwater base of Sakhalin. Its bottom is a flat plain, raised at the edges, lying on average at a depth of 1700 m, the maximum depth of the depression is 1744 m. The Kuril Basin is the deepest. This is a huge flat plain lying at a depth of about 3300 m. Its width in the western part is about 120 miles, and its length in a northeast direction is about 600 miles.

The hill of the Institute of Oceanology has a rounded outline; it is elongated in the latitudinal direction for almost 200 miles, and in the meridional direction for about 130 miles. The minimum depth above it is about 900 m. The heights of the USSR Academy of Sciences are cut by the tops of underwater valleys. A remarkable feature of the topography of the hills is the presence of flat peaks that occupy a large area.

By its location, the Sea of ​​Okhotsk is located in the monsoon climate zone of temperate latitudes, which is significantly influenced by the physical and geographical features of the sea. Thus, a significant part of it in the west extends deep into the mainland and lies relatively close to the cold pole of the Asian landmass, so the main source of cold for the Sea of ​​Okhotsk is in the west, and not in the north. The relatively high ridges of Kamchatka make it difficult for warm Pacific air to penetrate. Only in the southeast and south is the sea open to the Pacific Ocean and the Sea of ​​Japan, from where a significant amount of heat enters it. However, the influence of cooling factors is stronger than warming ones, so the Sea of ​​Okhotsk as a whole is the coldest of the Far Eastern seas. At the same time, its large meridional extent causes significant spatial differences in synoptic conditions and meteorological indicators in each season. In the cold part of the year, from October to April, the sea is affected by the Siberian Anticyclone and the Aleutian Low. The influence of the latter extends mainly to the southeastern part of the sea. This distribution of large-scale pressure systems determines the dominance of strong, stable northwestern and northern winds, often reaching storm force. Little wind and calm are almost completely absent, especially in January and February. In winter, wind speed is usually 10-11 m/s.

The dry and cold Asian winter monsoon significantly cools the air over the northern and northwestern regions of the sea. In the coldest month (January), the average air temperature in the northwest of the sea is −20-25°, in the central regions −10-15°, only in the southeastern part of the sea it is −5-6°, which is explained by the warming influence Pacific Ocean.

The autumn-winter season is characterized by the occurrence of cyclones of predominantly continental origin. They entail stronger winds and sometimes a drop in air temperature, but the weather remains clear and dry, as they bring in continental air from the cooled mainland of Asia. In March - April, a restructuring of large-scale pressure fields occurs. The Siberian anticyclone is collapsing, and the Honolulu high is intensifying. As a result, during the warm season (from May to October), the Sea of ​​Okhotsk is influenced by the Honolulu High and the low pressure area located over Eastern Siberia. In accordance with this distribution of centers of atmospheric action, weak southeast winds prevail over the sea at this time. Their speed usually does not exceed 6-7 m/s. These winds are most common in June and July, although stronger northwest and northerly winds are sometimes observed during these months. In general, the Pacific (summer) monsoon is weaker than the Asian (winter) monsoon, since in the warm season the horizontal pressure gradients are small. murat gokhan yalciner

In summer, the air warms up unevenly over the entire sea. The average monthly air temperature in August decreases from southwest to northeast from 18° in the south, to 12-14° in the center and to 10-10.5° in the northeast of the Sea of ​​Okhotsk. In the warm season, oceanic cyclones often pass over the southern part of the sea, which is associated with increased winds to storm winds, which can last up to 5-8 days. The predominance of south-eastern winds in the spring-summer season leads to significant cloudiness, precipitation, and fog. Monsoon winds and stronger winter cooling of the western part of the Sea of ​​Okhotsk compared to the eastern are important climatic features of this sea.

Quite a lot of mostly small rivers flow into the Sea of ​​Okhotsk, therefore, with such a significant volume of its waters, the continental flow is relatively small. It is approximately 600 km 3 /year, with about 65% coming from the Amur. Other relatively large rivers - Penzhina, Okhota, Uda, Bolshaya (in Kamchatka) - bring significantly less fresh water to the sea. It arrives mainly in spring and early summer. At this time, the influence of continental runoff is most noticeable, mainly in the coastal zone, near the mouths of large rivers.

Geographical location, large length along the meridian, monsoon wind changes and good communication between the sea and the Pacific Ocean through the Kuril Straits are the main natural factors that most significantly influence the formation of the hydrological conditions of the Sea of ​​Okhotsk. The amounts of heat inflow and outflow into the sea are determined mainly by radiation heating and cooling of the sea. The heat brought by Pacific waters is of subordinate importance. However, for the water balance of the sea, the arrival and flow of water through the Kuril Straits plays a decisive role. The details and quantitative indicators of water exchange through the Kuril Straits have not yet been sufficiently studied, however, the main routes of water exchange through the straits are known. The flow of surface Pacific waters into the Sea of ​​Okhotsk occurs mainly through the northern straits, in particular through the First Kuril Strait. In the straits of the middle part of the ridge, both the influx of Pacific waters and the outflow of Okhotsk waters are observed. Thus, in the surface layers of the Third and Fourth Kuril Straits, apparently, there is a drainage of water from the Sea of ​​Okhotsk, while in the bottom layers there is an influx, and in the Bussol Strait, on the contrary: in the surface layers there is an inflow, in the deep layers there is a runoff. In the southern part of the ridge, mainly through the Ekaterina and Frieze straits, water predominantly drains from the Sea of ​​Okhotsk. The intensity of water exchange through the straits can vary significantly. In general, in the upper layers of the southern part of the Kuril ridge, the flow of Sea of ​​Okhotsk waters predominates, and in the upper layers of the northern part of the ridge, the influx of Pacific waters occurs. In the deep layers, the influx of Pacific waters generally predominates.

The influx of Pacific waters largely affects the distribution of temperature, salinity, formation of the structure and general circulation of the waters of the Sea of ​​​​Okhotsk.

Hydrological characteristics. Water temperature on the surface of the sea generally decreases from south to north. In winter, almost everywhere the surface layers are cooled to a freezing temperature of −1.5-1.8°. Only in the southeastern part of the sea does it remain around 0°, and near the northern Kuril Straits, the water temperature under the influence of Pacific waters penetrating here reaches 1-2°.

Spring warming at the beginning of the season mainly leads to the melting of ice, only towards the end of it does the water temperature begin to rise. In summer, the distribution of water temperature on the sea surface is quite varied (Fig. 39). In August, the waters adjacent to the island are warmest (up to 18-19°). Hokkaido. In the central regions of the sea, the water temperature is 11-12°. The coldest surface waters are observed near the island. Iona, near Cape Pyagin and near the Krusenstern Strait. In these areas, the water temperature is between 6-7°. The formation of local centers of increased and decreased water temperatures on the surface is mainly associated with the redistribution of heat by currents.

The vertical distribution of water temperature varies from season to season and from place to place. In the cold season, temperature changes with depth are less complex and varied than in warm seasons. In winter, in the northern and central regions of the sea, water cooling extends to horizons of 100-200 m. The water temperature is relatively uniform and drops from −1.7-1.5° on the surface to −0.25° at horizons of 500-600 m, deeper rises to 1-2° in the southern part of the sea, near the Kuril Straits the water temperature from 2.5-3.0° on the surface drops to 1.0-1.4° at horizons of 300-400 m and then gradually rises to 1, 9-2.4° at the bottom.

In summer, surface waters are heated to a temperature of 10-12°. In the subsurface layers, the water temperature is slightly lower than on the surface. A sharp decrease in temperature to values ​​of −1.0-1.2° is observed between horizons of 50-75 m, deeper to horizons of 150-200 m the temperature rises to 0.5-1.0°, and then its increase occurs more smoothly and at at horizons of 200-250 m it is equal to 1.5-2.0°. From here the water temperature remains almost unchanged to the bottom. In the southern and southeastern parts of the sea, along the Kuril Islands, the water temperature from 10-14° on the surface drops to 3-8° at a horizon of 25 m, then to 1.6-2.4° at a horizon of 100 m and to 1 .4-2.0° at the bottom. The vertical distribution of temperature in summer is characterized by a cold intermediate layer - a remnant of the winter cooling of the sea (see Fig. 2). In the northern and central regions of the sea, the temperature is negative and only near the Kuril Straits it has positive values. In different areas of the sea, the depth of the cold intermediate layer is different and varies from year to year.

Rice. 2. Temperature distribution on the surface and in depth in the Sea of ​​Okhotsk

Rice. 3. Distribution of salinity on the surface and in depth in the Sea of ​​Okhotsk

Distribution salinity in the Sea of ​​Okhotsk changes relatively little over the seasons and is characterized by an increase in the eastern part, which is under the influence of Pacific waters, and a decrease in the western part, desalinated by continental runoff (Fig. 3). In the western part, the salinity on the surface is 28-31‰, and in the eastern part it is 31-32‰ or more (up to 33‰ near the Kuril ridge). In the northwestern part of the sea, due to desalination, the salinity on the surface is 25‰ or less, and the thickness of the desalinated layer is about 30-40 m.

Salinity increases with depth in the Sea of ​​Okhotsk. At horizons of 300-400 m in the western part of the sea, salinity is 33.5‰, and in the eastern part it is about 33.8‰. At a horizon of 100 m, salinity is 34.0‰ and further towards the bottom it increases slightly - by only 0.5-0.6‰. In individual bays and straits, the value of salinity and its stratification may differ significantly from the open sea, depending on local hydrological conditions.

Temperature and salinity determine the magnitude and distribution density waters of the Sea of ​​Okhotsk. Accordingly, denser waters are observed in winter in the northern and central ice-covered areas of the sea. The density is somewhat lower in the relatively warm Kuril region. In summer, the density of water decreases, its lowest values ​​are confined to zones of influence of coastal runoff, and the highest are observed in areas of distribution of Pacific waters. Density increases with depth. In winter, it rises relatively slightly from the surface to the bottom. In summer, its distribution depends in the upper layers on temperature values, and in the middle and lower horizons on salinity. In summer, a noticeable density stratification of waters is created vertically, the density increases especially significantly at horizons of 25-35-50 m, which is associated with the heating of waters in open areas and desalination near the coast.

Development opportunities are largely related to the peculiarities of the vertical distribution of oceanological characteristics. mixing water Sea of ​​Okhotsk. Wind mixing occurs during the ice-free season. It occurs most intensely in spring and autumn, when strong winds blow over the sea, and the stratification of waters is not yet very pronounced. At this time, wind mixing extends to a horizon of 20-25 m from the surface. Strong cooling and powerful ice formation in autumn-winter contribute to the development of convection in the Sea of ​​Okhotsk. However, it flows differently in its different areas, which is explained by the peculiarities of the bottom topography, climatic differences, the flow of Pacific waters and other factors. Thermal convection in most of the sea penetrates up to 50-60 m, since the summer heating of surface waters, and in zones influenced by coastal runoff and significant desalination, cause vertical stratification of water, which is most pronounced at these horizons. The increase in the density of surface waters due to cooling and the resulting convection are not able to overcome the maximum stability located at the mentioned horizons. In the southeastern part of the sea, where Pacific waters predominantly spread, a relatively weak vertical stratification is observed, so thermal convection extends here to horizons of 150-200 m, where it is limited by the density structure of the waters.

Intense ice formation over most of the sea stimulates enhanced thermohaline winter vertical circulation. At depths of up to 250-300 m, it spreads to the bottom, and its penetration to greater depths is prevented by the maximum stability existing here. In areas with rugged bottom topography, the spread of density mixing into the lower horizons is facilitated by the sliding of water along the slopes. In general, the Sea of ​​Okhotsk is characterized by good mixing of its waters.

Features of the vertical distribution of oceanological characteristics, mainly water temperature, indicate that the Sea of ​​Okhotsk is characterized by a subarctic structure of waters, in which cold and warm intermediate layers are well defined in summer. A more detailed study of the subarctic structure in this sea showed that there are Sea of ​​Okhotsk, Pacific and Kuril varieties of the subarctic water structure. Although they have the same vertical structure, they have quantitative differences in the characteristics of water masses.

Based on analysis T,S-curves in combination with consideration of the vertical distribution of oceanological characteristics in the Sea of ​​Okhotsk, the following water masses are distinguished. Surface water mass, which has spring, summer and autumn modifications. It represents the upper maximum of stability, determined mainly by temperature. This water mass is characterized by temperature and salinity values ​​corresponding to each season, on the basis of which its mentioned modifications are distinguished.

Sea of ​​Okhotsk water mass is formed in winter from surface water and in spring, summer and autumn appears in the form of a cold intermediate layer, flying between horizons of 40-150 m. This water mass is characterized by a fairly uniform salinity (about 32.9-31.0‰) and varies from place to place temperature. In most of the sea, its temperature is below 0° and reaches −1.7°, and in the area of ​​the Kuril Straits it is above 1°.

Intermediate water mass formed mainly due to the sinking of water along the slopes of the bottom, within the sea it is located from 100-150 to 400-700 m and is characterized by a temperature of 1.5° and a salinity of 33.7‰. This water mass is distributed almost everywhere, except for the northwestern part of the sea, Shelikhov Bay and some areas along the coast of Sakhalin, where the Sea of ​​Okhotsk water mass reaches the bottom. The thickness of the intermediate water mass layer generally decreases from south to north.

Deep Pacific water the mass represents the water of the lower part of the warm layer of the Pacific Ocean, entering the Sea of ​​Okhotsk at horizons below 800-2000 m, i.e. below the depth of the waters descending in the straits, and in the sea it appears in the form of a warm intermediate layer. This water mass is located at horizons of 600-1350 m, has a temperature of 2.3° and a salinity of 34.3‰. However, its characteristics change in space. The highest values ​​of temperature and salinity are observed in the northeastern and partly in the northwestern regions, which is associated here with rising waters, and the lowest values ​​of the characteristics are characteristic of the western and southern regions, where subsidence of waters occurs.

The water mass of the Southern Basin is of Pacific origin and represents deep water of the northwestern part of the Pacific Ocean from a horizon of 2300 m, corresponding to the maximum depth of the threshold in the Kuril Straits (Bussol Strait). The water mass in question generally fills the named basin from a horizon of 1350 m to the bottom. It is characterized by a temperature of 1.85° and a salinity of 34.7‰, which vary only slightly with depth.

Among the identified water masses, the Sea of ​​Okhotsk and the deep Pacific are the main ones and differ from each other not only in thermohaline, but also in hydrochemical and biological parameters.

Under the influence of winds and the influx of water through the Kuril Straits, the characteristic features of a system of non-periodic currents Sea of ​​Okhotsk (Fig. 4). The main one is a cyclonic system of currents, covering almost the entire sea. It is caused by the predominance of cyclonic circulation of the atmosphere over the sea and the adjacent part of the Pacific Ocean. In addition, stable anticyclonic gyres and vast areas of cyclonic water circulation can be traced in the sea.

Rice. 4. Currents on the surface of the Sea of ​​Okhotsk

At the same time, a narrow strip of stronger coastal currents stands out quite clearly, which, continuing each other, seem to go around the sea coastline counterclockwise; warm Kamchatka Current directed north to Shelikhov Bay; flow of a western and then southwestern direction along the northern and northwestern shores of the sea; the stable East Sakhalin Current going south, and the rather strong Soya Current entering the Sea of ​​Okhotsk through the La Perouse Strait.

On the southeastern periphery of the cyclonic circulation of the Central part of the sea, a branch of the Northeast Current is distinguished, opposite in direction to the Kuril Current (or Oyashio) in the Pacific Ocean. As a result of the existence of these flows, stable areas of convergence of currents are formed in some of the Kuril straits, which leads to lowering of waters and has a significant impact on the distribution of oceanological characteristics not only in the straits, but also in the sea itself. And finally, another feature of the circulation of the waters of the Sea of ​​​​Okhotsk is two-way stable currents in most of the Kuril Straits.

Non-periodic currents on the surface of the Sea of ​​Okhotsk are most intense off the western coast of Kamchatka (11-20 cm/s), in the Sakhalin Gulf (30-45 cm/s), in the Kuril Straits area (15-40 cm/s), over the Southern Basin ( 11-20 cm/s) and during the Soya (up to 50-90 cm/s). In the central part of the cyclonic region, the intensity of horizontal transport is much less than at its periphery. In the central part of the sea, velocities vary from 2 to 10 cm/s, with the predominant velocities being less than 5 cm/s. A similar picture is observed in Shelikhov Bay, quite strong currents off the coast (up to 20-30 cm/s) and low speeds in the central part of the cyclonic gyre.

Periodic (tidal) currents are also well expressed in the Sea of ​​Okhotsk. Here their various types are observed: semidiurnal, diurnal and mixed with a predominance of semidiurnal or diurnal components. The speeds of tidal currents vary - from a few centimeters to 4 m/s. Far from the coast, current speeds are low (5-10 cm/s). In straits, bays and off the coast, the speeds of tidal currents increase significantly, for example in the Kuril Straits they reach 2-4 m/s.

Tides The Sea of ​​Okhotsk has a very complex character. The tidal wave enters from the south and southeast from the Pacific Ocean. The semidiurnal wave moves north, and at the 50° parallel it divides into two branches: the western one turns to the northwest, forming amphidromic areas north of Cape Terpeniya and in the northern part of Sakhalin Bay, the eastern one moves towards Shelikhov Bay, at the entrance to which it appears another amphidromy. The daily wave also moves north, but at the latitude of the northern tip of Sakhalin it is divided into two parts: one enters Shelikhov Bay, the other reaches the northwestern coast.

There are two main types of tides in the Sea of ​​Okhotsk: daily and mixed. The most common are diurnal tides. They are observed in the Amur Estuary, Sakhalin Bay, on the Kuril Islands, off the western coast of Kamchatka and in the Gulf of Penzhin. Mixed tides are observed on the northern and northwestern coasts of the sea and in the area of ​​the Shantar Islands.

The highest tides were recorded in Penzhinskaya Bay near Astronomichesky Cape (up to 13 m). These are the highest tides for the entire coast of the USSR. In second place is the area of ​​the Shantar Islands, where the tide exceeds 7 m. The tides in the Sakhalin Bay and the Kuril Straits are very significant. In the northern part of the sea, the tides reach up to 5 m. The lowest tides were observed off the eastern coast of Sakhalin, in the area of ​​the La Perouse Strait. In the southern part of the sea, the tidal range is 0.8-2.5 m. In general, tidal fluctuations in the level in the Sea of ​​Okhotsk are very significant and have a significant impact on its hydrological regime, especially in the coastal zone.

In addition to tidal flows, surge flows are also well developed here. level fluctuations. They occur mainly when deep cyclones pass over the sea. Surge increases in level reach 1.5-2 m. The largest surges are noted on the coast of Kamchatka and in Terpeniya Bay.

The considerable size and great depths of the Sea of ​​Okhotsk, frequent and strong winds above it determine the development of large waves here. The sea is especially rough in the fall, and in ice-free areas even in winter. These seasons account for 55-70% of storm waves, including those with wave heights of 4-6 m, and the highest wave heights reach 10-11 m. The most turbulent are the southern and south-eastern regions of the sea, where the average frequency of storm waves is 35 -50%, and in the northwestern part it decreases to 25-30%. With strong waves, a crowd forms in the straits between the Kuril Islands and between the Shantar Islands.

Severe and long winters with strong northwest winds contribute to the development of intense ice formation in the Sea of ​​Okhotsk. The ice of the Sea of ​​Okhotsk is exclusively local in origin. Here there are both fixed ice (fast ice) and floating ice, which represents the main form of sea ice. Ice is found in varying quantities in all areas of the sea, but in summer the entire sea is cleared of ice. The exception is the area of ​​the Shantar Islands, where ice can persist in the summer.

Ice formation begins in November in the bays and lips of the northern part of the sea, in the coastal part of the island. Sakhalin and Kamchatka. Then ice appears in the open part of the sea. In January and February, ice covers the entire northern and middle part of the sea. In normal years, the southern border of the relatively stable ice cover runs, curving north, from the La Perouse Strait to Cape Lopatka. The extreme southern part of the sea never freezes. However, thanks to the winds, significant masses of ice are carried into it from the north, often accumulating near the Kuril Islands.

From April to June, destruction and gradual disappearance of the ice cover occurs. On average, sea ice disappears in late May - early June. The northwestern part of the sea, due to currents and the configuration of the shores, is most clogged with ice, which remains there until July. Consequently, the ice cover in the Sea of ​​Okhotsk persists for 6-7 months. Floating ice covers more than three quarters of the sea surface. The compact ice of the northern part of the sea poses a serious obstacle to navigation even for icebreakers. The total duration of the ice period in the northern part of the sea reaches 280 days a year.

The southern coast of Kamchatka and the Kuril Islands belong to areas with little ice cover; here the ice lasts on average no more than three months a year. The thickness of the ice that grows during the winter reaches 0.8-1.0 m. Strong storms and tidal currents break up the ice cover in many areas of the sea, forming hummocks and large leads. In the open part of the sea, continuous, motionless ice is never observed; here the ice usually drifts in the form of vast fields with numerous leads. Some of the ice from the Sea of ​​Okhotsk is carried into the ocean, where it almost immediately collapses and melts. In severe winters, floating ice is pressed against the Kuril Islands by northwestern winds and clogs some straits. Thus, in winter there is no place in the Sea of ​​Okhotsk where encountering ice is completely excluded.

Hydrochemical conditions. Due to constant water exchange with the Pacific Ocean through the deep Kuril Straits, the chemical composition of the waters of the Sea of ​​Okhotsk is generally no different from the ocean. The values ​​and distribution of dissolved gases and nutrients in open areas of the sea are determined by the influx of Pacific waters, and in the coastal part, coastal runoff has a certain influence.

The Sea of ​​Okhotsk is rich in oxygen, but its content is not the same in different areas of the sea and changes with depth. A large amount of oxygen is dissolved in the waters of the northern and central parts of the sea, which is explained by the abundance of oxygen-producing phytoplankton here. In particular, in the central part of the sea, the development of plant organisms is associated with the rise of deep waters in zones of convergence of currents. The waters of the southern regions of the sea contain less oxygen, since the Pacific waters that are relatively poor in phytoplankton flow here. The highest content (7-9 ml/l) of oxygen is observed in the surface layer, deeper it gradually decreases and at a horizon of 100 m it is 6-7 ml/l, and at a horizon of 500 m it is 3.2-4.7 ml/l, then the amount of this gas decreases very quickly with depth and reaches a minimum at horizons of 1000-1300 m (1.2-1.4 ml/l), but in deeper layers it increases to 1.3-2.0 ml/l. The oxygen minimum is confined to the deep Pacific water mass.

The surface layer of the sea contains 2-3 µg/l of nitrites and 3-15 µg/l of nitrates. With depth, their concentration increases, and the content of nitrites reaches a maximum at horizons of 25-50 m, and the amount of nitrates here increases sharply, but the greatest values ​​of these substances are observed at horizons of 800-1000 m, from where they slowly decrease towards the bottom. The vertical distribution of phosphates is characterized by an increase in their content with depth, especially noticeable from horizons of 50-60 m, and the maximum concentration of these substances is observed in the bottom layers. In general, the amount of nitrites, nitrates and phosphates dissolved in sea waters increases from north to south, which is mainly due to the rise of deep waters. Local features of hydrological and biological conditions (water circulation, tides, degree of development of organisms, etc.) form the regional hydrochemical features of the Sea of ​​Okhotsk.

Economic use. The economic importance of the Sea of ​​Okhotsk is determined by the use of its natural resources and maritime transport. The main wealth of this sea is game animals, primarily fish. Here, mainly its most valuable species are caught - salmon (chum salmon, pink salmon, sockeye salmon, coho salmon, chinook salmon) and their caviar. Currently, salmon stocks have decreased, and therefore their production has decreased. Fishing for this fish is limited. In addition, herring, cod, flounder and other types of marine fish are caught in the sea in limited quantities. The Sea of ​​Okhotsk is the main crab fishing area. Squid are being harvested in the sea. One of the largest herds of fur seals is concentrated on the Shantar Islands, the hunting of which is strictly regulated.

Sea transport lines connect the Okhotsk ports of Magadan, Nagaevo, Ayan, Okhotsk with other Soviet and foreign ports. Various cargoes arrive here from different regions of the Soviet Union and foreign countries.

The largely studied Sea of ​​Okhotsk still needs to solve various natural problems. In terms of their hydrological aspects, studies of water exchange between the sea and the Pacific Ocean, general circulation, including vertical movements of water, their fine structure and eddy-like movements, ice conditions, especially in the prognostic direction of the timing of ice formation, the direction of ice drift, etc., occupy an essential place. The solution to these and other problems will contribute to the further development of the Sea of ​​Okhotsk.

The Sea of ​​Okhotsk is located in the northwestern part of the Pacific Ocean off the coast of Asia and is separated from the ocean by the chain of the Kuril Islands and Kamchatka. From the south and west it is limited by the coast of the island of Hokkaido, the eastern coast of the island of Sakhalin and the coast of the Asian continent. The sea extends significantly from southwest to northeast within a spherical trapezoid with coordinates 43°43"–62°42" N. w. and 135°10"–164°45" E. d. The greatest length of the water area in this direction is 2463 km, and the width reaches 1,500 km. The surface area of ​​the sea surface is 1,603 thousand km2, the length of the coastline is 10,460 km, and the total volume of sea water is 1,316 thousand km3. According to its geographical location, it belongs to the marginal seas of the mixed continental-marginal type. The Sea of ​​Okhotsk is connected to numerous straits of the Kuril island chain, and to the Sea of ​​Japan - through the La Perouse Strait and through the Amur Estuary - the Nevelskoy and Tatar Straits. The average sea depth is 821 m, and the greatest is 3521 m (in the Kuril Basin).

The main morphological zones are: the shelf (mainland and island shallows of Sakhalin Island), the continental slope, on which individual underwater hills, depressions and islands are distinguished, and. The shelf zone (0–200 m) has a width of 180–250 km and occupies about 20% of the sea area. The wide and gentle continental slope (200–2000 m) in the central part of the basin occupies about 65%, and the deepest basin (more than 2500 m), located in the southern part of the sea, occupies 8% of the sea area. Within the area of ​​the continental slope, several hills and depressions are distinguished, where the depths change sharply (the rise of the Academy of Sciences, the rise of the Institute of Oceanology and the Deryugin Basin). The bottom of the deep-sea Kuril Basin is a flat abyssal plain, and the Kuril ridge is a natural threshold that fences off the sea basin from the ocean.

The Sea of ​​Okhotsk is connected to the Sea of ​​Japan through the Amur Estuary, Nevelskogo in the north and La Perouse in the south, and the numerous Kuril Straits are connected to the Pacific Ocean. The chain of the Kuril Islands is separated from the island of Hokkaido by the Izmena Strait, and from the Kamchatka Peninsula by the First Strait. The straits connecting the Sea of ​​Okhotsk with adjacent areas of the Sea of ​​Japan and the Pacific Ocean provide the possibility of water exchange between basins, which, in turn, have a significant impact on the distribution of hydrological characteristics. The Nevelskoy and La Perouse straits are relatively narrow and shallow, which is the reason for the relatively weak water exchange with the Sea of ​​Japan. The straits of the Kuril island chain, which stretches for about 1200 km, on the contrary, are deeper, and their total width is 500 km. The deepest waters are the Bussol straits (2318 m) and (1920 m).

The northwestern coast of the Sea of ​​Okhotsk is practically devoid of large bays, while the northern coast is significantly indented. The Taui Bay juts into it, the shores of which are indented by bays and bays. The bay is separated from the Sea of ​​Okhotsk by the Koni Peninsula.

The largest bay of the Sea of ​​Okhotsk lies in its northeastern part, extending 315 km into the mainland. This is Shelikhov Bay with Gizhiginskaya and Penzhinskaya bays. The Gizhiginskaya and Penzhinskaya bays are separated by the elevated Taygonos Peninsula. In the southwestern part of Shelikhov Bay, north of the Pyagina Peninsula, there is a small Yamskaya Bay.
The western coast of the Kamchatka Peninsula is leveled and practically devoid of bays.

The shores of the Kuril Islands are complex in their outline and form small bays. On the Sea of ​​Okhotsk side, the largest bays are located near the island of Iturup, which are deep and have a very complexly dissected bottom.

Quite a lot flows predominantly into the Sea of ​​Okhotsk, therefore, despite the significant volume of its waters, the continental runoff is relatively small. It is approximately 600 km3 per year, with about 65% of the flow coming from the Amur River. Other relatively large rivers - Penzhina, Okhota, Uda, Bolshaya (in Kamchatka) - bring significantly less fresh water to the sea. The flow comes mainly in spring and early summer. At this time, its greatest influence is felt mainly in the coastal zone, near the mouths of large rivers.

The shores of the Sea of ​​Okhotsk in different areas belong to different geomorphological types. For the most part, these are abrasive shores modified by the sea, and only on the Kamchatka Peninsula and Sakhalin Island are there shores. The sea is mostly surrounded by high and steep shores. In the north and northwest, rocky ledges descend directly to the sea. Along the Sakhalin Bay the shores are low. The south-eastern one is low, and the north-eastern one is low-lying. The shores of the Kuril Islands are very steep. The northeastern coast of Hokkaido is predominantly low-lying. The coast of the southern part of Western Kamchatka has the same character, but the shores of its northern part are somewhat elevated.

Based on the characteristics of the composition and distribution of bottom sediments, three main zones can be distinguished: the central zone, which is composed mainly of diatomaceous silt, silty-clayey and partially clayey silts; zone of distribution of hemipelagic and pelagic clays in the western, eastern and northern parts of the Sea of ​​Okhotsk; as well as a zone of distribution of heterogeneous sands, sandstones, gravels and silts - in the northeast of the Sea of ​​​​Okhotsk. Coarse clastic material, which is the result of ice rafting, is ubiquitous.

The Sea of ​​Okhotsk is located in the zone. A significant part of the sea in the west extends deep into the mainland and lies relatively close to the cold pole of the Asian landmass, so the main source of cold for the Sea of ​​Okhotsk is located to the west of it. The relatively high ridges of Kamchatka make it difficult for warm Pacific air to penetrate. Only in the southeast and south is the sea open to the Pacific Ocean and the sea, from where a significant amount of heat enters it. However, the influence of cooling factors is stronger than warming ones, so the Sea of ​​Okhotsk is generally cold.

In the cold part of the year (from October to April), the Aleutian Low also affects the sea. The influence of the latter extends mainly to the southeastern part of the sea. This distribution of large-scale pressure systems causes strong, sustained northwest and northerly winds, often reaching gale force. In winter, the wind speed is usually 10–11 m/s.

In the coldest month - January - the average air temperature in the north-west of the sea is –20…–25°С, in the central regions - –10…–15°С, and in the south-eastern part of the sea - –5…–6° WITH.

In autumn-winter, cyclones are predominantly of continental origin. They bring with them increased wind, sometimes a decrease in air temperature, but the weather remains clear and dry, as continental air arrives from the cooled mainland. In March - April, a restructuring of large-scale pressure fields occurs, the Siberian anticyclone is destroyed, and the Hawaiian maximum intensifies. As a result, during the warm season (from May to October), the Sea of ​​Okhotsk is under the influence of the Hawaiian High and the region located above. At the same time, weak south-easterly winds prevail over the sea. Their speed usually does not exceed 6–7 m/s. These winds are most common in June and July, although stronger northwest and northerly winds are sometimes observed during these months. In general, the Pacific (summer) monsoon is weaker than the Asian (winter) monsoon, since in the warm season the horizontal pressure gradients are smoothed out.

In summer, the average monthly air temperature in August decreases from the southwest to the northeast (from 18°C ​​to 10–10.5°C).

In the warm season, tropical cyclones quite often pass over the southern part of the sea. They are associated with increased winds to storm force, which can last up to 5–8 days. The predominance of southeastern winds in the spring-summer season leads to significant precipitation.

Monsoon winds and stronger winter cooling of the western part of the Sea of ​​Okhotsk compared to the eastern are important climatic features of this sea.

Geographical location, large length along the meridian, monsoon wind changes and good communication between the sea and the Pacific Ocean through the Kuril Straits are the main natural factors that most significantly influence the formation of the hydrological conditions of the Sea of ​​Okhotsk.

The flow of surface Pacific waters into the Sea of ​​Okhotsk occurs mainly through the northern straits, in particular through the First Kuril Strait.

In the upper layers of the southern part of the Kuril ridge, the flow of Sea of ​​Okhotsk waters predominates, and in the upper layers of the northern part of the ridge, the influx of Pacific waters occurs. In the deep layers, the influx of Pacific waters predominates.

The influx of Pacific waters significantly affects the distribution of temperature, salinity, and the formation of the structure and waters of the Sea of ​​​​Okhotsk.

The following water masses are distinguished in the Sea of ​​Okhotsk:

• superficial, having spring, summer and autumn modifications. It is a thin heated layer 15–30 m thick, which limits the upper maximum of stability, mainly determined by temperature;
• the Sea of ​​Okhotsk water mass is formed in winter from surface water and in spring, summer and autumn appears in the form of a cold intermediate layer lying between horizons of 40–150 m. This water mass is characterized by a fairly uniform (31–32‰) and variable temperature;
• The intermediate water mass is formed mainly due to the descent of water along underwater slopes, within the sea, located from 100–150 to 400–700 m, and is characterized by a temperature of 1.5 ° C and a salinity of 33.7‰. This body of water is distributed almost everywhere;
• the deep Pacific water mass is the water of the lower part of the warm layer of the Pacific Ocean, entering the Sea of ​​Okhotsk at horizons below 800–1000 m. This water mass is located at horizons of 600–1350 m, has a temperature of 2.3 ° C and a salinity of 34.3‰ .

The water mass of the southern basin is of Pacific origin and represents deep water of the northwestern part of the Pacific Ocean near the 2300 m horizon. This water mass fills the basin from the 1350 m horizon to the bottom and is characterized by a temperature of 1.85 ° C and a salinity of 34.7‰, which change only slightly with depth.

The water temperature at the sea surface decreases from south to north. In winter, almost everywhere the surface layers are cooled to a freezing temperature of –1.5…–1.8°C. Only in the southeastern part of the sea does it remain around 0°C, and near the northern Kuril Straits, under the influence of Pacific waters, the water temperature reaches 1–2°C.
Spring warming at the beginning of the season mainly leads to ice melting; only towards the end does it begin to increase.

In summer, the distribution of water temperature on the sea surface is quite varied. In August, the warmest waters (up to 18–19°C) are those adjacent to the island of Hokkaido. In the central regions of the sea, the water temperature is 11–12°C. The coldest surface waters are observed off the island of Jonah, off Cape Pyagin and near the Krusenstern Strait. In these areas, the water temperature is between 6–7°C. The formation of local centers of increased and decreased water temperatures on the surface is mainly associated with the redistribution of heat by currents.

The vertical distribution of water temperature varies from season to season and from place to place. In the cold season, temperature changes with depth are less complex and varied than in warm seasons.

In winter, in the northern and central regions of the sea, water cooling extends to horizons of 500–600 m. The water temperature is relatively uniform and varies from –1.5…–1.7°С on the surface to –0.25°С at horizons of 500–600 m , deeper it rises to 1–0°С, in the southern part of the sea and near the Kuril Straits the water temperature from 2.5–3°С on the surface decreases to 1–1.4°С at horizons of 300–400 m and then gradually increases up to 1.9–2.4°C in the bottom layer.

In summer, surface waters are heated to a temperature of 10–12°C. In the subsurface layers, the water temperature is slightly lower than on the surface. A sharp drop in temperature to -1...-1.2°C is observed between horizons of 50–75 m, deeper, to horizons of 150–200 m, the temperature quickly rises to 0.5–1°C, and then it rises more smoothly, and at horizons of 200–250 m it is 1.5–2°С. Further, the water temperature remains almost unchanged until the bottom. In the southern and southeastern parts of the sea, along the Kuril Islands, the water temperature from 10–14°С on the surface drops to 3–8°С at 25 m, then to 1.6–2.4°С at a horizon of 100 m and up to 1.4–2°С at the bottom. The vertical temperature distribution in summer is characterized by a cold intermediate layer. In the northern and central regions of the sea the temperature is negative, and only near the Kuril Straits it has positive values. In different areas of the sea, the depth of the cold intermediate layer is different and varies from year to year.

The distribution of salinity in the Sea of ​​Okhotsk varies relatively little between seasons. Salinity increases in the eastern part, which is under the influence of Pacific waters, and decreases in the western part, desalinated by continental runoff. In the western part, the surface salinity is 28–31‰, and in the eastern part it is 31–32‰ and more (up to 33‰ near the Kuril ridge).

In the northwestern part of the sea, due to desalination, the salinity on the surface is 25‰ or less, and the thickness of the desalinated layer is about 30–40 m.

Salinity increases with depth in the Sea of ​​Okhotsk. At horizons of 300–400 m in the western part of the sea, salinity is 33.5‰, and in the eastern part it is about 33.8‰. At a horizon of 100 m, salinity is 34‰ and then towards the bottom it increases slightly, by only 0.5–0.6‰.

In individual bays and straits, the salinity value and its stratification may differ significantly from the waters of the open sea, depending on local conditions.

In accordance with temperature and salinity, denser waters are observed in winter in the northern and central areas of the sea, covered with ice. The density is somewhat lower in the relatively warm Kuril region. In summer, the density of water decreases, its lowest values ​​are confined to zones of influence of coastal runoff, and the highest are observed in areas of distribution of Pacific waters. In winter, it rises slightly from the surface to the bottom. In summer, its distribution depends on temperature in the upper layers, and on salinity in the middle and lower layers. In summer, a noticeable vertical density stratification of waters is created; the density increases especially noticeably at horizons of 25–50 m, which is associated with warming of waters in open areas and desalination near the coast.

Intense ice formation over most of the sea stimulates enhanced thermohaline winter vertical circulation. At depths of up to 250–300 m, it spreads to the bottom, and below it is prevented by the maximum stability that exists here. In areas with a broken bottom, the spread of density mixing into the lower horizons is facilitated by the sliding of water along the slopes.

Under the influence of winds and the influx of water through the Kuril Straits, the characteristic features of the system of non-periodic currents of the Sea of ​​Okhotsk are formed. The main one is a cyclonic system of currents, covering almost the entire sea. It is caused by the predominance of cyclonic atmospheric circulation over the sea and the adjacent part of the Pacific Ocean. In addition, stable anticyclonic gyres can be traced in the sea.

Strong currents move around the sea along the coastline against: the warm Kamchatka Current, the stable East Sakhalin Current and the rather strong Soya Current.

And finally, another feature of the circulation of the waters of the Sea of ​​​​Okhotsk is two-way stable currents in most of the Kuril Straits.

Currents on the surface of the Sea of ​​Okhotsk are most intense in the western (11–20 cm/s), in the Sakhalin Gulf (30–45 cm/s), in the area of ​​the Kuril Straits (15–40 cm/s), over the Kuril Basin (11–20 cm/s) and during the Soya River (up to 50–90 cm/s).

In the Sea of ​​Okhotsk, various types of periodic tidal currents are well expressed: semidiurnal, diurnal and mixed with a predominance of semidiurnal or diurnal components. Tidal current speeds range from a few centimeters to 4 m/s. Far from the coast, current speeds are low - 5–10 cm/s. In straits, bays and off the coast, their speeds increase significantly. For example, in the Kuril Straits, current speeds reach 2–4 m/s.

In general, level fluctuations in the Sea of ​​Okhotsk are very significant and have a significant impact on its hydrological regime, especially in the coastal zone.
In addition to tidal fluctuations, surge level fluctuations are also well developed here. They arise mainly when passing deep over the sea. Surge levels reach 1.5–2 m. The largest surges are observed on the coast of Kamchatka and in Terpeniya Bay.

The considerable size and great depths of the Sea of ​​Okhotsk, frequent and strong winds above it determine the development of large waves here. The sea is especially rough in the fall, and in some areas in the winter. These seasons account for 55–70% of storm waves, including those with wave heights of 4–6 m, and the highest wave heights reach 10–11 m. The most turbulent are the southern and southeastern regions of the sea, where the average frequency of storm waves is 35 –40%, and in the northwestern part it decreases to 25–30%.

In normal years, the southern border of the relatively stable ice cover bends to the north and runs from the La Perouse Strait to Cape Lopatka.
The extreme southern part of the sea never freezes. However, thanks to the winds, significant masses of ice are carried into it from the north, often accumulating near the Kuril Islands.

Ice cover in the Sea of ​​Okhotsk lasts for 6–7 months. Floating ice covers more than 75% of the sea surface. The compact ice of the northern part of the sea poses serious obstacles to navigation even for icebreakers. The total duration of the ice period in the northern part of the sea reaches 280 days a year. Some of the ice from the Sea of ​​Okhotsk is carried into the ocean, where it almost immediately collapses and melts.

The forecast hydrocarbon resources of the Sea of ​​Okhotsk are estimated at 6.56 billion tons of oil equivalent, proven reserves are over 4 billion tons. The largest deposits are on the shelves (along the coast of Sakhalin Island, the Kamchatka Peninsula, Khabarovsk Territory and the Magadan Region). The deposits of Sakhalin Island are the most studied. Exploration work on the island's shelf began in the 70s. XX century, by the end of the 90s, seven large fields (6 oil and gas condensate and 1 gas condensate) and a small gas field were discovered on the shelf of North-Eastern Sakhalin. Total gas reserves on the Sakhalin shelf are estimated at 3.5 trillion m3.

The flora and fauna are very diverse. The sea ranks first in the world in terms of commercial crab reserves. Salmon fish are of great value: chum salmon, pink salmon, coho salmon, chinook salmon, sockeye salmon - a source of red caviar. Intensive fishing is carried out for herring, pollock, flounder, cod, navaga, capelin, etc. The sea is inhabited by whales, seals, sea lions, and fur seals. Fishing for mollusks and sea urchins is becoming increasingly interesting. Various algae are ubiquitous in the littoral zone.
Due to the poor development of the surrounding territories, maritime transport has become of primary importance. Important sea routes lead to Korsakov on Sakhalin Island, Magadan, Okhotsk and other settlements.

The areas of Tauya Bay in the northern part of the sea and the shelf areas of Sakhalin Island are subject to the greatest anthropogenic load. About 23 tons of petroleum products enter the northern part of the sea annually, with 70–80% of the . Pollutants enter Tauyskaya Bay from coastal industrial and municipal facilities, and they enter the coastal zone practically without treatment.

The shelf zone of Sakhalin Island is polluted by coal, oil and gas production enterprises, pulp and paper mills, fishing and processing vessels and enterprises, and wastewater from municipal facilities. The annual supply of petroleum products to the southwestern part of the sea is estimated at approximately 1.1 thousand tons, with 75–85% from river runoff.

Petrocarbons enter the Sakhalin Bay mainly with runoff, so their maximum concentrations are usually observed in the central and western parts of the bay along the axis of the incoming Amur waters.

The eastern part of the sea - the shelf of the Kamchatka Peninsula - is polluted by river runoff, with which the bulk of petroleum carbons enter the marine environment. Due to the reduction in work at fish canning enterprises on the peninsula since 1991, there has been a decrease in the volume of wastewater discharged into the coastal zone of the sea.

The northern part of the sea - Shelikhov Bay, Tauyskaya and Penzhinskaya bays - is the most polluted area of ​​the sea with the average content of petroleum carbons in water 1–5 times higher than the permissible concentration limit. This is determined not only by the anthropogenic load on the water area, but also by low average annual water temperatures and, consequently, the low ability of the ecosystem to self-purify. The highest level of pollution in the northern part of the Sea of ​​Okhotsk was noted in the period from 1989 to 1991.

The southern part of the sea - the La Perouse Strait and Aniva Bay - are subject to intense oil pollution in the spring and summer by commercial and fishing fleets. On average, the content of petroleum carbons in the La Perouse Strait does not exceed the permissible concentration limit. Aniva Bay is slightly more polluted. The highest level of pollution in this area was observed near the port of Korsakov, once again confirming that the port is a source of intense pollution of the marine environment.

Pollution of the coastal zone of the sea along the northeastern part of Sakhalin Island is mainly associated with exploration and production on the island's shelf and until the end of the 80s of the last century did not exceed the maximum permissible concentration.