Sea of ​​Okhotsk (shores in Russia). Give a description of the Sea of ​​Okhotsk according to the plan

The Sea of ​​Okhotsk is located in the northwestern part of the Pacific Ocean and, according to its geographical position, belongs to the type of marginal seas. It washes the coast of Asia in the north and is separated from the ocean in the southeast by the ridges of the Kuril Islands and the Kamchatka Peninsula. Its western border is drawn along the east coast of about. Sakhalin and about. Hokkaido.

Sea straits

The Amur Estuary, Nevelskoy in the north and Laperouse in the south straits connect the Sea of ​​Okhotsk with the Sea of ​​Japan, and the numerous Kuril straits with the Pacific Ocean. The chain of the Kuril Islands is separated from about. Hokkaido Treason, and from the Kamchatka Peninsula - the First Kuril Strait. The deepest straits of the island chain are Bussol and Krusenstern. Of the other largest straits: Ekaterina, Friza, Rikord, Fourth Kuril. According to the classification of N. N. Zubov, the Sea of ​​Okhotsk belongs to the basin seas, since the depth of the straits is much less than the maximum depths of the bottom of the basin.

Coastline

The coastline of the Sea of ​​Okhotsk has complex outlines. Its bends, connected with the protrusions of large capes and peninsulas, form bays and bays. It is most sinuous in the southwestern and northeastern parts of the sea. In the southwest, the largest are the Aniva and Patience bays, separated from the open sea by the Tonino-Aniva and Patience peninsulas, respectively. In the northeast of Sakhalin is slightly indented, but on the shore, in close proximity to the sea, there is a chain of large lagoons called bays: Lunsky, Nabilsky, Nyisky, Chaivo, Piltun. These lagoons are separated by spits, between which there are narrow shallow passages. The lagoons are shallow and in most cases covered with algae. North of the hall. Piltun along the eastern coast of Sakhalin is a chain of lakes and lagoons, which, as a rule, have rounded outlines and relatively small sizes. Sakhalin Bay protrudes for 100 km between the north of about. Sakhalin and the coast of the mainland. It is limited by Cape Elizabeth in the east and Cape Alexandra in the west, the width of the bay between them is about 200 km. Two smaller bays protrude into the eastern shore of the Sakhalin Bay: Pomr and Baikal, and into the western shore - the bays of Ekaterina, Reinecke, Shchastya, etc.

From the Sakhalin Bay to the Udskaya Bay there is the most indented section of the coast with numerous large bays: Alexandra, Academia, which in turn are wedged into the bays of Nikolai, Ulbansky and Konstantin; Tugursky, separated from the hall. Academy on the Tugur Peninsula. The northwestern coast of the Sea of ​​Okhotsk is practically devoid of large bays, while the northern coast is significantly indented. The Tauiskaya Bay protrudes into it, the shores of which are indented with bays and bays (the Motykleisky, Akhmatonsky and Odyan bays). The bay is separated from the Sea of ​​Okhotsk by the Koni Peninsula. Of the smaller bays on the northern coast of the Sea of ​​Okhotsk, it should be noted the Eirinei Bay and the bays of Ushki, Shelting, Zabiyak, Babushkin, Kekurny. The largest bay of the Sea of ​​Okhotsk lies in its northeastern part, extending 315 km into the mainland. This is the hall. Shelikhov with Gizhinsky and Penzhinsky lips. South boundary of the hall. Shelikhov is served by a line connecting Cape Tolstoy on the Pyagin Peninsula with Cape Utkholoksky on the Kamchatka Peninsula. The Gizhinskaya and Penzhinskaya bays are separated by the elevated Taigonos Peninsula. The Penzhina Bay narrows sharply to 40 km with the Elistratov Peninsula in the west and the Mametchinsky Peninsula in the east. This narrowness is called the throat. In the southwestern part of the hall. Shelikhov, to the north of the Pyagin Peninsula, there is a small Yamskaya Bay with Perevalochny and Malka-chansky bays. The western coast of the Kamchatka Peninsula is flattened and practically devoid of bays. The shores of the Kuril Islands are complex in outline and form small bays. On the Sea of ​​Okhotsk side, the largest bays are located near about. Iturup: Good Beginning, Kuibyshev, Kuril, Prostor, as well as the Lion's Mouth, etc. The bays are deep-water and have a very dissected bottom.

Islands

The islands in the Sea of ​​Okhotsk are very diverse both in size and shape, and in origin. Here there are single islands and archipelagos, the islands in which are located in a compact group or elongated in the form of a ridge. Mainland islands and islands of the transition zone are distinguished. Continental islands are land masses located within a single block of the earth's crust with the mainland. The islands of the transitional zone include linearly elongated archipelagos crowning the crests of powerful curved underwater cordillera ridges. They are called island arcs. King notes a characteristic regularity in the distribution of island chains in the transition zone. They are usually double. The concave inner ridge is occupied by volcanic structures, and the outer ridge is occupied by drained ledges of the folded base of the Cordillera. From the mainland islands off the coast of Eastern Sakhalin, small islands are known: Tyuleniy and the Rock Danger Stone. Tyuleny Island has a flat top and steep shores. An accumulative surface spit departs from the southern tip. Rock Danger Stone - a small group of bare stones in the strait. La Perouse.

Iona Island is located 200 km north of about. Sakhalin. Its height is 150 m, the coast is rocky and almost sheer. The Shantar Islands lie in the northwest of the Sea of ​​Okhotsk. They are an archipelago of 15 islands with an area of ​​about 2,500 km. The largest islands: Big Shantar (area 1790 km 2), Feklistova (about 400 km 2), Small Shantar (about 100 km 2), Belichiy (about 70 km 2). The climate on the islands is harsh. Of the islands on the northern coast, the most significant are located in the Tauy Bay. These are the islands of Zavyalov and Spafaryeva. Spafareva Island rises to 575 m, and about. Zavyalova is mountainous and reaches a height of 1130 m. Its slopes are covered with shrubs, the shores are rocky. In the Shelikhov Hall, the islands are located near the coast and are insignificant in size. The most distant from the coastline are the Yamsky (Atykan, Matykil), as well as the small islands of Kokontse, Baran, Hatemalyu. They are located at a distance of up to 20 km east of the Pyagin Peninsula. Small islands: Third, Extreme, Dobzhansky, Rovny, Jagged, Cone, Chemeivytegartynup - are located in the Penzhina Bay. Off the coast of western Kamchatka, there is only one noticeable island - Ptichy, located north of Cape Khairyuzovo. The garland of islands in the transitional zone, which form the Greater Kuril Range, stretched from the Shiretoko Peninsula (Hokkaido Island) in the southwest to Cape Lopatka (Kamchatka Peninsula) in the northeast. Its length is about 1300 km. In terms of plan, the ridge has the shape of an angle equal to 150 °, with a top in the area of ​​the strait. Bussol facing the Pacific Ocean. It consists of 30 large, 20 small islands and rocks. The total area of ​​the islands of the Great Kuril ridge is 15.6 thousand km 2. The deep straits of Bussol and Kruzenshtern divide the archipelago into three parts: the Southern, Middle and Northern Kuriles.

The Southern Kuriles include the large islands of the Greater Kuril Ridge: Kunashir, Iturup Urup, as well as the small islands of the Black Brothers and Broughton. A significant area of ​​the large islands is hilly and terraced. Above them rise volcanic structures with a height of 1200-1800 m (Tyatya, Mendeleeva, Atsonupuri, Be-rutarube, etc.) - Urup Island is somewhat different in its massive base. The Middle Kuriles are represented by the smallest islands of the ridge: Ketoi, Ushishir, Rasshua, Matua, Raikoke. The largest of them - about. Simushir. The islands are above-water peaks of single volcanoes reaching heights of up to 1500 m. The Northern Kuriles include the islands of Shi-ashkotan, Ekarma, Chirinkotan, Onekotan, Kharim-kotan, Makanrushi, Antsiferova, Paramushir, Shumshu, Atlasov. They do not form a single chain. The largest of them (the islands of Paramushir and Shumshu) are located on the eastern outskirts of the Great Kuril Ridge. On about. Paramushir volcanoes exceed 1300 m (Karpinsky, Chikurachki), somewhat lower than Ebeko volcano (1183 m). The highest point of the island belongs to the top of the Fussa volcano - 1772 m. Of the other islands, one can mention the islands of Onekotan and Shiashkotan - groups of two volcanoes connected by low bridges, as well as the highest island of the Great Kuril Ridge - Atlasova, which is the top of the Alaid volcano and reaches the mark 2339 m

The Sea of ​​Okhotsk is the 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.
The area is 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 depressions (in the south) and the TINRO depression. In the eastern part there is the Kuril basin, in which 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 south-west from the Sea of ​​Japan is it separated by conditional lines: Cape Yuzhny - Cape Tyk and in the Laperouse Strait Cape Crillon - Cape Soya. The southeastern boundary 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 expanse of the sea extends from north to south from 62°42′ to 43°43′ N. sh. and from west to east from 134°50′ to 164°45′ E. e. The sea is considerably elongated from the southwest to the 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, maximum depth 3916 m. marginal type.

There are few islands in the Sea of ​​Okhotsk. The largest border island is Sakhalin. The Kuril ridge has about 30 large, many small islands and rocks. The Kuril Islands are located in the seismic activity belt, which includes more than 30 active and 70 extinct volcanoes. Seismic activity is manifested on the islands and under water. In the latter case, tsunami waves are formed. In addition to the named "marginal" islands in the sea, there are the islands of Shantarsky, Spafaryeva, Zavyalova, Yamsky and the small island of Iona - the only one of them remote from the coast.
With a large length, the coastline is indented relatively weakly. At the same time, it forms several large bays (Aniva, Patience, Sakhalin, Academies, Tugursky, Ayan, Shelikhov) and bays (Udskaya, Tauiskaya, 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, Shelikhov Bay, is located. Of the smaller bays of the northern part, the most famous are the Eyriney Bay and the bays of Shelting, Zabiyaka, Babushkin, 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 Patience bays, Odessa Bay on Iturup Island.

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

Extraction of hydrocarbon raw materials on the shelf of Sakhalin.

The rivers Amur, Okhota, Kukhtui flow into it.

Sea of ​​Okhotsk Cape Velikan, Sakhalin Island

Main ports:
on the mainland - Magadan, Ayan, Okhotsk (portpoint); 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 the Evensk. lam - "sea"), as well as the Kamchatka Sea. The Japanese traditionally called this sea Hokkai (北海), literally "North Sea". But since this name now 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 water area of ​​the Sea of ​​Okhotsk consists of internal waters, the territorial sea and the exclusive economic zone of two coastal states - Russia and Japan. According to 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 a territorial sea and an exclusive economic zone of two states, but it is not one, 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 an area elongated in the meridional direction, traditionally referred to in the English-language literature as Peanut Hole, which is not included in the exclusive economic zone and is an open sea outside the jurisdiction of Russia; in particular, any country in the world has the right to fish here 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 expressly prohibit their vessels from fishing in this area of ​​the sea.

On November 13-14, 2013, the Subcommittee established within the framework of 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 application of the Russian Federation to recognize the bottom of the above section 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 filed in 2001, and filed in a new edition in early 2013, and the central part of the Sea of ​​Okhotsk outside the exclusive economic zone of the Russian Federation was recognized Russian continental shelf.
Consequently, in the central part, other states are prohibited from extracting "sedentary" biological resources (for example, crab) and developing subsoil. Catching other biological resources, such as fish, is not subject to the restrictions of the continental shelf. Consideration of the application on the merits became possible due to the position of Japan, which, by an official note dated May 23, 2013, confirmed its consent for the Commission to consider the essence of the application without regard to resolving 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 a depth of about 50-150 meters, there is an intermediate cold layer of water, the temperature of which does not change during 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 runoff, the water temperature is around 0 °C in winter and 8-15 °C in summer.
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" (year of construction 1976), analogue of the icebreaker "Admiral Makarov" (year of construction 1975)

From December 30, 2010 to January 31, 2011, a rescue operation was carried out in the Sea of ​​Okhotsk, which received extensive media coverage.
The operation itself was large-scale, according to the Deputy Minister of Transport Viktor Olersky and the head of the Federal Agency for Fishery Andrei Krayny, rescue operations on such a scale have not been carried out in Russia for 40 years.
The cost of the operation was in the range of 150-250 million rubles, 6,600 tons of diesel fuel were spent on it.
15 ships, on which there were about 700 people, were captured by ice.
The operation was carried out by the forces of the icebreaking flotilla: the icebreakers Admiral Makarov and Krasin, the icebreaker Magadan and the tanker Victoria worked as auxiliary vessels. The coordinating 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 vessels got out on their own, the icebreakers rescued four vessels: the trawler Cape Elizabeth, the research vessel Professor Kizevetter (first half of January, Admiral Makarov), the refrigerator Coast of Hope and the mother ship Sodruzhestvo.
The first aid was provided to the seiner Cape Elizabeth, whose captain led his vessel after the introduction of a ban on entering the area.
As a result, Cape Elizabeth was frozen into ice in the area of ​​the Sakhalin Bay. Sea of ​​Okhotsk

The second liberated vessel was the Professor Kizevetter, whose captain, as a result of the investigation, was deprived of his diploma for six months.
In the area of ​​January 14, the icebreakers gathered together the remaining ships in distress, after which the icebreakers escorted both vessels of the caravan on a coupler.
After the “whiskers” of the “Commonwealth” broke off, it was decided to first drive a refrigerator through heavy ice.
The wiring was suspended in the region on January 20 due to weather conditions, but on January 24, the Coast of Hope refrigerator was brought to clean water.
On January 25, after bunkering, the Admiral Makarov returned to escort the mother ship.
On January 26, the towing "whiskers" broke again, we had to lose time for the delivery of new ones by helicopter.
On January 31, the floating base Sodruzhestvo was also taken out of ice captivity, the operation ended at 11:00 Vladivostok time.

Red Cape, Three Brothers Islands

SHELEKHOVA 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 got its name in honor of G. I. Shelikhov.
Length - 650 km, width at the entrance - 130 km, maximum width - 300 km, depths up to 350 m.
In the northern part, the Taigonos Peninsula is divided into the Gizhiginskaya Bay and the Penzhina Bay. The rivers Gizhiga, Penzhina, Yama, Malkachan flow into the bay.
Covered with ice from December to May. The tides are irregular, semi-diurnal. In the Penzhina Bay, they reach the maximum value for the Pacific Ocean.
The bay is rich in fish resources. Fishing objects are herring, halibut, flounder, Far Eastern saffron cod.
In the southern part of the Shelikhov Bay there is a small archipelago of the Yamskiye Islands.
In Shelikhov Bay, tides reach 14 m.

Sakhalin Bay, swans have arrived Sea of ​​Okhotsk

SAKHALIN BAY
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.
It is wide in the northern part, narrows to the south and passes into the Amur Estuary. Width up to 160 km Nevelskoy Strait connected with the Tatar Strait and the Sea of ​​Japan.
From November to June it is covered with ice.
The tides are irregular daily, up to 2-3 m.
Industrial fishing (salmon, cod) is carried out in the waters of the bay.
On the shore of the bay is the port of Moskalvo.

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-Anivsky peninsulas. From the south it is wide open to the La Perouse Strait.
The origin of the name of the bay is most likely connected with the Ainu words "an" and "willow". The first is usually translated as "available, located", and the second as "mountain range, rock, peak"; thus, "Aniva" can be translated as "having ridges" or "located among the ridges (mountains)".
Width 104 km, length 90 km, maximum depth 93 meters. The narrowed part of the bay is known as Salmon Bay. The warm current Soya affects the temperature regime and the dynamics of currents inside the bay, which is changeable.

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

The island got its name from the Manchu name of the Amur River - "Sakhalyan-ulla", which means "Black River" - this name, printed on the map, was erroneously attributed to Sakhalin, and in further editions of the maps it was already 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. Kruzenshtern explored most of the coast of Sakhalin and concluded that Sakhalin was a peninsula. In 1808, Japanese expeditions led by Matsuda Denjuro and Mamiya Rinzo proved that Sakhalin was an island. Most European cartographers were skeptical of the Japanese data. For a long time, on various maps, Sakhalin was designated either as an island or a peninsula. Only in 1849 did the expedition under the command of G. I. Nevelsky put an end to this issue, passing on the military transport ship Baikal between Sakhalin and the mainland. This strait was subsequently named after Nevelskoy.

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

BAY OF PATIENCE
Gulf of Patience is a bay of the Sea of ​​Okhotsk off the southeastern coast of Sakhalin Island. In the eastern part it is partially bounded by the Patience Peninsula.
The bay was discovered in 1643 by the Dutch navigator M. G. De Vries and named by him the Gulf of Patience, since his expedition had to wait here for a long time thick fog, which made it impossible to continue sailing.
The bay is 65 km long, about 130 km wide, and up to 50 m deep. The Poronai River flows into the bay.
In winter, the bay freezes over.
The waters of the bay are rich in biological resources, including chum salmon and pink salmon.
The port of Poronaysk is located in Patience 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 in a slightly convex arc.
The length is about 1200 km. The total area is 10.5 thousand km². To the south of them is 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 are of great military-strategic and economic importance. 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 the Hokkaido prefecture.

Relate to the regions of the Far North
The climate on the islands is marine, rather severe, 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, the 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 temperature in August in the southern part of the Kuril Islands is +17 °C, in the north - +10 °C.

List of islands with an area of ​​more than 1 km² in the direction from north to south.
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"
Macanrushi 49 1169 49°46" 154°26"
Onecotan 425 1324 49°27" 154°46"
Harimkotan 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"
Russhua 67 948 47°45" 153°01"
Ushishir Islands 5 388 — —
Ryponkicha 1.3 121 47°32" 152°50"
Yankich 3.7 388 47°31" 152°49"
Ketoi 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"
Tanfilyev 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 at the edge of the Okhotsk plate. It sits above a subduction zone where the Pacific Plate is being swallowed up. Most of the islands are mountainous. The highest height 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, there are hot mineral springs. Large tsunamis are not uncommon. The most famous are the tsunami of November 5, 1952 in 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
Basic physical and geographical features.
The straits connecting the Sea of ​​Okhotsk with the Pacific Ocean and the Sea of ​​Japan and their depths are of great importance, since they determine the possibility of water exchange. The Nevelskoy and La Perouse straits are comparatively 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 somewhat 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 much less than the maximum depth of the sea, therefore, r, which separates the sea basin from the ocean.
The most important for water exchange with the ocean are the straits of Bussol and Krusenstern, as 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. The Friza, Fourth Kuril, Rikord and Nadezhda straits are of less importance, the depths of which 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 not identical in external forms and structure, in different regions belong to different geomorphological types. From fig. 38 shows that for the most part these are abrasion shores altered by the sea, only in the west of Kamchatka and in the east of Sakhalin there are accumulative shores. In general, the sea is surrounded by high and steep shores. In the north and northwest, rocky ledges descend directly to the sea. A less high, and then a low-lying mainland coast approaches the sea near the Sakhalin Bay. The southeastern coast of Sakhalin is low, and the northeastern coast is low. very abrupt. 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 relief 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 mainland. The width of the continental shoal in the area of ​​the Ayano-Okhotsk coast is approximately 100 miles, in the area of ​​the Uda Bay - 140 miles. Between the meridians of Okhotsk and Magadan, its width increases to 200 miles. From the western edge of the basin of the sea is the island sandbar of Sakhalin, from the eastern edge - the continental shelf 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 separate underwater heights, depressions and trenches stand out.
The deepest southern part of the sea deeper than 2500 m, which is a section of the bed, occupies 8% of the total area. It is elongated as a strip along the Kuril Islands, gradually narrowing from 200 km against about. Iturup up to 80 km against the Krusenstern Strait. Great depths and significant slopes of the bottom distinguish the southwestern part of the sea from the northeastern part, which lies on the continental shelf.
Of the large elements of the relief of the bottom 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 basin, the northwestern Deryugin basin, and the southern deep-water Kuril basin. The depressions are connected by gutters: Makarov, P. Schmidt and Lebed. To the northeast of the TINRO depression, the Shelikhov Bay trough extends.

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

The least deep TINRO basin is located to the 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 to the east of the underwater base of Sakhalin. Its bottom is a flat, elevated plain 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, its length in the northeast direction is about 600 miles.

The hill of the Institute of Oceanology has a rounded shape, it is extended in the latitudinal direction by almost 200 miles, and in the meridional direction by about 130 miles. The minimum depth above it is about 900 m. The upland of the USSR Academy of Sciences is indented by the peaks of underwater valleys. A remarkable feature of the relief of the hills is the presence of their flat tops, which 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 deeply protrudes into the mainland and lies relatively close to the cold pole of the Asian land, 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 effect of cooling factors is stronger than warming factors, so the Sea of ​​Okhotsk is generally the coldest of the Far Eastern seas. At the same time, its large meridional extent causes significant spatial differences in the synoptic situation and meteorological indicators in each season. In the cold part of the year, from October to April, the Siberian anticyclone and the Aleutian low act on the sea. The influence of the latter extends mainly to the southeastern part of the sea. Such a distribution of large-scale baric systems determines the dominance of strong, stable northwestern and northern winds, often reaching storm strength. Low winds and calms are almost completely absent, especially in January and February. In winter, the 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 effect Pacific Ocean.

The autumn-winter time is characterized by the emergence of cyclones of predominantly continental origin. They entail intensification, winds, and sometimes a decrease in air temperature, but the weather remains clear and dry, as they bring in continental air from the chilled mainland of Asia. In March-April, large-scale baric fields are restructured. The Siberian anticyclone is collapsing and the Honolulu High is getting stronger. As a result, during the warm season (May to October), the Sea of ​​Okhotsk is under the influence of the Honolulu High and the area of ​​low pressure located over Eastern Siberia. In accordance with this distribution of the centers of action of the atmosphere, weak southeasterly winds prevail over the sea at this time. Their speed usually does not exceed 6-7 m/s. Most often, these winds are observed in June and July, although stronger northwesterly and northerly winds are sometimes observed in these months. In general, the Pacific (summer) monsoon is weaker than the Asian (winter) monsoon, since the horizontal pressure gradients are small in the warm season.

bay Nagaevo

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 quite often pass over the southern part of the sea, which is associated with an increase in wind to a storm, which can last up to 5-8 days. The predominance of southeasterly 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 few mostly small rivers flow into the Sea of ​​Okhotsk, therefore, with such a significant volume of its waters, the continental runoff is relatively small. It is equal to approximately 600 km3/year, while about 65% is provided by the Amur. Other relatively large rivers - Penzhina, Okhota, Uda, Bolshaya (in Kamchatka) - bring much less fresh water into 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 mouth areas of large rivers.

Geographical position, large length along the meridian, monsoonal change of winds and good connection of the sea with the Pacific Ocean through the Kuril Straits are the main natural factors that most significantly affect the formation of the hydrological conditions of the Sea of ​​Okhotsk. The values ​​of heat input and output in the sea are determined mainly by radiative heating and cooling of the sea. The heat brought by the Pacific waters is of subordinate importance. However, for the water balance of the sea, the inflow and outflow 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 studied enough, but the main ways 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. In the straits of the middle part of the ridge, both the inflow 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 runoff of water from the Sea of ​​Okhotsk, while in the bottom layers there is an inflow, and in the Bussol Strait, on the contrary: in the surface layers, an inflow, in the deep layers, a drain. In the southern part of the ridge, mainly through the straits of Ekaterina and Friza, there is mainly a runoff of water 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 runoff of the Sea of ​​Okhotsk waters predominates, and in the upper layers of the northern part of the ridge, Pacific waters enter. In the deep layers, the influx of Pacific waters generally prevails.
The inflow 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 characteristic.
The sea surface temperature generally decreases from south to north. In winter, almost everywhere, the surface layers cool down 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 reaches 1–2° under the influence of the Pacific waters penetrating here.

Spring warming at the beginning of the season mainly goes 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 diverse (Fig. 39). In August, the warmest (up to 18-19 °) waters adjacent to the island. Hokkaido. In the central regions of the sea, the water temperature is 11-12°. The coldest surface waters are observed near about. Iona, near Cape Pyagin and near the Kruzenshtern Strait. In these areas, the water temperature is kept within 6-7 °. The formation of local centers of increased and decreased water temperature 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, the change in temperature with depth is 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. rises to 1–2° in the southern part of the sea; near the Kuril Straits, the water temperature drops from 2.5–3.0° on the surface to 1.0–1.4° at 300–400 m horizons and then gradually rises to 1, 9-2.4° at the bottom.

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 decrease in temperature to values ​​of −1.0–1.2° is observed between horizons of 50–75 m; in horizons of 200-250 m it is 1.5-2.0°. From here, the temperature of the water almost does not change to the bottom. In the southern and southeastern parts of the sea, along the Kuril Islands, the water temperature drops from 10–14° at the surface to 3–8° at a 25 m horizon, then to 1.6–2.4° at a 100 m horizon and down to 1 .4—2.0° at the bottom. The vertical temperature distribution 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 in it is negative, and only near the Kuril Straits does it have 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 with 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, 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 the horizons of 300–400 m in the western part of the sea, the salinity is 33.5‰, and in the eastern part it is about 33.8‰. At the 100 m horizon, the salinity is 34.0‰, and further towards the bottom it increases insignificantly, by only 0.5–0.6‰. In individual bays and straits, salinity and its stratification may differ significantly from the open sea, depending on local hydrological conditions.

Temperature and salinity determine the values ​​and distribution of the density of the waters of the Sea of ​​Okhotsk. In accordance with this, denser waters are observed in winter in the northern and central ice-covered regions of the sea. The density is somewhat less in the relatively warm Kuril region. In summer, the water density decreases, its lowest values ​​are confined to the zones of influence of coastal runoff, and the highest values ​​are observed in the 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 in the upper layers depends on the temperature values, and on the middle and lower horizons on salinity. In summer, a noticeable density stratification of water along the vertical is created, the density increases especially significantly at horizons of 25–35–50 m, which is associated with the heating of water in open areas and desalination near the coast.

Cape Nyuklya (Sleeping Dragon) near Magadan

The possibilities for the development of water mixing in the Sea of ​​Okhotsk are largely related to the peculiarities of the vertical distribution of oceanological characteristics. Wind mixing is carried out in the ice-free season. It flows most intensively 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 the autumn-winter time contributes to the development of convection in the Sea of ​​Okhotsk. However, it proceeds differently in its different regions, which is explained by the features of the bottom topography, climatic differences, the inflow 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 the zones of influence of coastal runoff and significant freshening, cause vertical stratification of waters, which is most pronounced on the indicated horizons. The increase in the density of surface waters due to cooling and the resulting convection are not able to overcome the stability maximum located at the aforementioned horizons. In the southeastern part of the sea, where Pacific waters mainly spread, relatively weak vertical stratification is observed; therefore, thermal convection propagates here to 150–200 m horizons, where it is limited by the density structure of the waters.
Intense ice formation over most of the sea excites an 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 a 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 water structure, in which cold and warm intermediate layers are well pronounced in summer. A more detailed study of the subarctic structure in this sea has shown that the Sea of ​​Okhotsk, Pacific, and Kuril varieties of the subarctic water structure exist in it. With the same nature of the vertical structure, they have quantitative differences in the characteristics of water masses.

Based on the analysis of T, S-curves in combination with a consideration of the vertical distribution of oceanological characteristics in the Sea of ​​Okhotsk, the following water masses are distinguished. Surface water mass with spring, summer and autumn modifications. It represents the upper maximum of stability, mainly due to temperature. This water mass is characterized by temperature and salinity 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 it manifests itself 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 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 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, which enters the Sea of ​​Okhotsk at horizons below 800–2000 m, i.e., below the depth of the waters descending in the straits, and manifests itself in the sea as a warm intermediate layer. This water mass is located on the horizons of 600-1350 m, has a temperature of 2.3°C 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 the rise of waters, and the smallest values ​​of the characteristics are characteristic of the western and southern regions, where the waters sink.
The water mass of the Southern Basin is of Pacific origin and represents the 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 considered water mass generally fills the named basin from the 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 indicators.

Under the influence of winds and water inflow through the Kuril Straits, characteristic features of the system of non-periodic currents of the Sea of ​​Okhotsk are formed (Fig. 41). The main one is the cyclonic system of currents, covering almost the entire sea. It is due to the predominance of cyclonic circulation of the atmosphere over the sea and the adjacent part of the Pacific Ocean. In addition, stable anticyclonic circulations and extensive 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 bypass the coastline of the sea counterclockwise; the warm Kamchatka current directed to the north into Shelikhov Bay; flow of western and then south-western direction along the northern and north-western coasts of the sea; the steady East Sakhalin Current going south, and the rather strong Soya Current entering the Sea of ​​Okhotsk through the Laperouse 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 streams, stable areas of convergence of currents are formed in some of the Kuril Straits, which leads to subsidence of waters and has a significant effect on the distribution of oceanological characteristics not only in the straits, but also in the sea itself. And finally, one more 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 Sakhalin Bay (30–45 cm/s), in the region of the Kuril Straits (15–40 cm/s), over the South 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 on its periphery. In the central part of the sea, velocities vary from 2 to 10 cm/s, with velocities below 5 cm/s predominating. A similar picture is also observed in the Shelikhov Bay, rather strong currents near the coast (up to 20–30 cm/s) and low velocities 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 velocities of tidal currents are different - from a few centimeters to 4 m/s. Away from the coast, the current velocities are low (5–10 cm/s). In straits, bays, and off the coast, the velocities of tidal currents increase significantly; for example, in the Kuril Straits they reach 2–4 m/s.
The tides of the Sea of ​​Okhotsk have a very complex character. A tidal wave enters from the south and southeast from the Pacific Ocean. The semidiurnal wave moves to the north, and at the 50° parallel it is divided into two branches: the western one turns to the northwest, forming amphidromic regions to the north of Cape Terpeniya and in the northern part of Sakhalin Bay, the eastern one moves towards the Shelikhov Bay, at the entrance to which arises another amphidrome. The diurnal 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: diurnal and mixed. The most common are diurnal tides. They are observed in the Amur Estuary, Sakhalin Bay, the Kuril Islands, off the western coast of Kamchatka and in Penzhinsky Bay. 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 the Penzhina Bay near Cape Astronomichesky (up to 13 m). These are the highest tides for the entire coast of the USSR. In second place is the region of the Shantar Islands, where the tide exceeds 7 m. The tides are very significant in the Sakhalin Bay and in the Kuril Straits. In the northern part of the sea, the tides reach up to 5 m. In the southern part of the sea, the tides are 0.8–2.5 m. In general, tidal level fluctuations in the Sea of ​​Okhotsk are very significant and have a significant effect on its hydrological regime, especially in the coastal zone.
In addition to tidal fluctuations, surge fluctuations in the level are also well developed here. They occur mainly during the passage of deep cyclones over the sea. Surge rises in the level reach 1.5–2 m. The largest surges are noted on the coast of Kamchatka and in the Gulf of Patience.

The significant size and great depths of the Sea of ​​Okhotsk, frequent and strong winds over it determine the development of large waves here. The sea is especially stormy in autumn, and in ice-free areas 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 restless are the southern and southeastern regions of the sea, where the average frequency of storm waves is 35 -50%, and in the northwestern part it decreases to 25-30%. In case of 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 of local formation. There are both fixed ice (fast ice) and floating ice, which are the main form of sea ice. In one quantity or another, ice is found in all areas of the sea, but in summer the entire sea is cleared of ice. The exception is the region of the Shantar Islands, where ice can persist in summer.
Ice formation begins in November in the bays and bays 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 parts of the sea. In ordinary years, the southern boundary of a relatively stable ice cover curves northward from the La Perouse Strait to Cape Lopatka. The extreme southern part of the sea never freezes. However, due to the winds, significant masses of ice are carried into it from the north, often accumulating near the Kuril Islands.

From April to June there is a destruction and gradual disappearance of the ice cover. On average, the ice in the sea disappears in late May - early June. The northwestern part of the sea, due to the currents and the configuration of the coasts, is most of all 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's surface. Close-knit ice in the northern part of the sea is 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 are areas with low ice cover, where ice stays 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 the ice cover in many areas of the sea, forming hummocks and large leads. In the open part of the sea, solid immovable ice is never observed; usually, ice drifts here in the form of vast fields with numerous leads. Part of the ice from the Sea of ​​Okhotsk is carried into the ocean, where it breaks up and melts almost immediately. In severe winters, floating ice is pressed against the Kuril Islands by northwestern winds and clogs some of the straits. Thus, in the winter time in the Sea of ​​Okhotsk there is no such place where an encounter with ice would be completely excluded.

hydrochemical conditions.
Due to the constant water exchange with the Pacific Ocean through the deep Kuril Straits, the chemical composition of the waters of the Sea of ​​Okhotsk generally does not differ from that of the ocean. The values ​​and distribution of dissolved gases and biogenic substances in the open areas of the sea are determined by the inflow of Pacific waters, and in the coastal part, coastal runoff has a certain effect.

The Sea of ​​Okhotsk is rich in oxygen, but its content is not the same in different areas of the sea and varies 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 the zones of convergence of currents. The waters of the southern regions of the sea contain a smaller amount of oxygen, since the Pacific waters, which are relatively poor in phytoplankton, come here. The highest content (7-9 ml/l) of oxygen is observed in the surface layer, deeper it gradually decreases and is 6-7 ml/l at the 100 m horizon, and 3.2-4.7 ml/l at the 500 m horizon, further, the amount of this gas decreases very rapidly with depth and reaches a minimum (1.2–1.4 ml/l) at horizons of 1000–1300 m; however, 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 the horizons of 25-50 m, and the amount of nitrates sharply increases here, but the greatest values ​​of these substances are noted at the horizons of 800-1000 m, from where they slowly decrease to the bottom. The vertical distribution of phosphates is characterized by an increase in their content with depth, which is 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 the waters of the sea 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 significance 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, especially fish. Here, mainly its most valuable species are mined - salmon (chum, pink salmon, sockeye salmon, coho salmon, chinook salmon) and their caviar. Currently, salmon stocks have decreased, so their production has decreased. The catch of this fish is limited. In addition, herring, cod, flounder and other types of sea fish are caught in the sea in limited quantities. The Sea of ​​Okhotsk is the main area for crab fishing. Squid are being harvested in the sea. One of the largest herds of fur seals is concentrated on the Shantar Islands, the extraction 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 come 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, an essential place is occupied by studies of the water exchange of the sea with the Pacific Ocean, general circulation, including vertical movements of waters, 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. The solution of 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. Moscow publishing house. un-ta, 1982.
Leontiev V.V., Novikova K.A. Toponymic Dictionary of the North-East of the USSR. - Magadan: Magadan book publishing house, 1989, p 86
Leonov A.K. Regional oceanography. - Leningrad, Gidrometeoizdat, 1960. - T. 1. - S. 164.
Wikipedia site.
Magidovich IP, Magidovich VI Essays on the history of geographical discoveries. - Enlightenment, 1985. - T. 4.
http://www.photosight.ru/
photo: O.Smoly, A.Afanasiev, A.Gill, L.Golubtsova, A.Panfilov, T.Selena.

The Sea of ​​Okhotsk, whose resources are of great importance for states, is one of the largest seas belonging to the Pacific Ocean. Located off the coast of Asia. It is separated from the ocean by the islands - Hokkaido, the eastern coast of Sakhalin and the chain of the Kuril lands.

It is worth noting that this sea is considered the coldest of all located in the Far East. Even in summer, the temperature above it does not exceed 18 degrees on the south side, and in the northeast, thermometers show 10 degrees - this is the maximum figure.

Brief description of the Sea of ​​Okhotsk

It is cold and powerful. The Sea of ​​Okhotsk washes the shores of Japan and Russia. According to its outlines, the reservoir resembles an ordinary trapezoid. The sea stretches from the southwest to the northeast. The maximum length is 2.463 km and the maximum width is 1.500 km. The coastline is over 10,000 km long. The depth of the Sea of ​​Okhotsk (indicator of the maximum depression) is almost 4,000 km. The type of reservoir adjacent to the outskirts of the mainland is mixed.

Volcanic activity extends both to the surface and to the bottom of the sea. When a seismic movement or an explosion of an underwater volcano occurs underwater, it can cause huge tsunami waves.

hydronym

The Sea of ​​Okhotsk, whose resources are used in the national economic spheres of the two countries (Russia and Japan), got its name from the name of the Okhota River. According to official sources, earlier it was called Lamsky and Kamchatsky. In Japan, for a long time the sea was called "Northern". But due to confusion with another body of the same name, the hydronym was adapted and now the sea is called the Sea of ​​Okhotsk.

Importance of the Sea of ​​Okhotsk for Russia

It cannot be overestimated. Since 2014, the Sea of ​​Okhotsk belongs to the inland waters of the Russian Federation. The state makes full use of its resources. First of all, it is the main supplier of salmon fish species. These are chum salmon, sockeye salmon, chinook salmon and other members of the family. The extraction of caviar is organized here, which is highly valued. No wonder Russia is considered one of the largest suppliers of this product.

The problems of the Sea of ​​Okhotsk, however, as well as other water bodies, have led to a significant decrease in populations. It was for this state that it was necessary to limit the catch of fish. And this applies not only to the salmon family, but also to other species, such as herring, flounder, cod.

Industry

Russia has achieved great results in the development of industry on the shores of the Sea of ​​Okhotsk. First of all, these are ship repair enterprises and, of course, fish processing factories. These two areas were modernized in the 90s and are now of great importance for the economic development of the state. Nowadays, many commercial enterprises have appeared here.

Industry is also developing quite well on about. Sakhalin. Earlier, in tsarist times, it was perceived negatively, as it served as a place for exile of people objectionable to the rule. Now the picture has changed radically. The industry is flourishing, people themselves tend to come here in order to earn big money.

Kamchatka seafood processing enterprises entered the world market. Their products are highly appreciated abroad. It meets the standards and is quite popular in many countries.

Thanks to oil and gas deposits, Russia is a monopoly in this area. There is not a single state that could supply the same volumes of oil and gas to Europe. That is why a lot of money from the sovereign treasury is invested in these enterprises.

Islands

There are few islands in the Sea of ​​Okhotsk, the largest of them is Sakhalin. Its coastline is heterogeneous: lowlands are observed in the northeast, the southeast is slightly elevated above sea level, and there is a shallow in the west.

The Kuril Islands are of particular interest. They are small in size, there are about 30 large ones, but there are also smaller ones. Together they form a seismic belt - the largest on the planet. There are about 100 volcanoes on the Kuril Islands. Moreover, 30 of them are operational: they can constantly “excite” the Sea of ​​Okhotsk.

The resources of the Shantar Islands are fur seals. The largest concentration of this species is observed here. However, recently their production has been regulated in order to avoid complete extermination.

gulfs

The coastline of the reservoir is slightly indented, although it has a large length. There are practically no bays and bays in this area. The basin of the Sea of ​​Okhotsk is divided into three basins: the Kuril, TINRO and Deryugin basins.

The largest bays: Sakhalin, Tugursky, Shelikhov, etc. There are also several bays here - sea bays that cut deep into the land, which form the depression of large rivers. Among them are Penzhinskaya, Gizhiginskaya, Udskaya, Tauyskaya. Thanks to the bays, water exchange in the seas also occurs. And at the moment, scientists call this issue quite problematic.

Straits

They are part of the Okhotsk basin. This is the important element that connects the reservoir with and also with the Pacific Ocean. In addition, there are low and shallow and Nevelsk. They do not play a special role, since they are quite small. But the Krusenstern and Bussol straits are distinguished by a large area, while their maximum depth reaches 500 meters. In many ways, they regulate the salinity of the Sea of ​​Okhotsk.

Bottom and coastline

The depths of the Sea of ​​Okhotsk are not uniform. From the side of Sakhalin and the mainland, the bottom is represented by a shoal - a continuation of the Asian part of the mainland. Its width is approximately 100 km. The rest of the bottom (about 70%) is represented by the continental slope. Near the Kuril Islands, next to about. Iturup is a sore cavity. In this place, the depth of the Sea of ​​Okhotsk reaches 2,500 meters. At the bottom of the reservoir, two large towering sections of relief are distinguished with rather original names: the hill of the Institute of Oceanology and the USSR Academy of Sciences.

The coastline of the Sea of ​​Okhotsk belongs to different geomorphological forms. Most of them are high and steep slopes. Only the western territory of Kamchatka and the east of about. Sakhalin have a low-lying character. But the northern coast is significantly indented.

Water exchange

The continental runoff is small. This is due to the fact that all the rivers flowing into the Sea of ​​Okhotsk are not full-flowing, and cannot play a significant role. The most important is r. Cupid, it is on it that more than half of the total indicator of effluents falls. There are other relatively large rivers. This is Hunt, Uda, Bolshaya, Penzhina.

Hydrological characteristic

The reservoir is completely because the salinity of the Sea of ​​Okhotsk is quite high. It is 32-34 ppm. It decreases closer to the coast, reaching a mark of 30 ‰, and in the intermediate layer - 34 ‰.

Most of the territory is covered with floating ice in winter. The lowest water temperature during the cold season ranges from -1 to +2 degrees. In summer, the sea depths warm up to 10-18ºC.

An interesting fact: at a depth of 100 meters there is an intermediate layer of water, the temperature of which does not change throughout the year and is 1.7 ° C below zero.

Climate features

The Sea of ​​Okhotsk is located in temperate latitudes. This fact has a great influence on the mainland, providing the Aleutian minimum in the cold part of the year. It largely influences the northern winds that cause storms that continue throughout the winter.

In the warm season, weak southeasterly winds come from the mainland. Thanks to them, the air temperature rises to a large extent. However, cyclones come along with them, which can later form typhoons. The duration of such a typhoon can be from 5 to 8 days.

Sea of ​​Okhotsk: resources

They will be discussed further. It is known that the natural resources of the Sea of ​​Okhotsk are still poorly explored. The sea shelf with its hydrocarbon reserves is of the greatest value. Today, 7 are open on Sakhalin, Kamchatka, in the Khabarovsk Territory and the Magadan administrative center. The development of these deposits began in the 70s. However, in addition to oil, the main wealth of the Sea of ​​Okhotsk is flora and fauna. They are of great variety. Therefore, the industry is highly developed here. The most valuable species of salmon fish are found in the Sea of ​​Okhotsk. In the depths, squids are mined, and in terms of catching crabs, the reservoir is in first place in the world. Recently, mining conditions have become more strict and harsh. And there are restrictions on the catch of some fish.

Fur seals, whales, seals live in the northern waters of the sea. Catching these representatives of the animal world is strictly prohibited. In recent years, fishing is gaining popularity - catching sea urchins and shellfish. From the plant world, different types of seaweeds are important. Speaking about the use of the sea, it is worth noting its importance in the transport sector. She is a priority. Important maritime trade routes have been laid here, which connect the large cities of Korsakov (Sakhalin), Magadan, Okhotsk and others.

Ecological problems

The Sea of ​​Okhotsk, like other waters of the World Ocean, suffers from human activities. Environmental problems have been recorded here in the form of a runoff of oil products and residues of gas compounds. Also quite problematic are the waste of industrial and domestic enterprises.

The coastal zone began to be polluted from the time of the development of the first offshore fields, but until the end of the 80s it did not have such large-scale dimensions. Now human anthropogenic activity has reached a critical point and requires immediate resolution. The largest concentration of waste and pollution is concentrated off the coast of Sakhalin. This is mainly due to rich oil deposits.

The Sea of ​​Okhotsk is located between the waters of the Sea of ​​Japan and the Bering Sea.

This reservoir limits the territory of Japan and the Russian Federation and is the most important port point on the map of our country.

Previously, among the names of the sea were Lamskoe, Kamchatskoe, and the Japanese - Hokkai, i.e. North.

Shores of the Sea of ​​Okhotsk

This reservoir is considered to be one of the largest and deepest in Russia, as well as the coolest Far Eastern sea. The area of ​​the water area is 1603 km 2, and the depth is over 800 m on average. The maximum depth indicator is almost 4 thousand meters. The coastal boundary of the reservoir is quite even, several bays pass along it. However, in the northern part of the waters there are many rocks and sharp cliffs. For the territory of this sea, storm warnings are completely normal.

The sea is separated from the Pacific Ocean by the Kuriles. We are talking about 3 dozen small areas of land that are in a seismically hazardous zone due to the abundance of volcanoes. Also, the waters of the Pacific Ocean and the Sea of ​​Okhotsk are separated by Kamchatka and the island of Hokkaido. And the largest island of this area is Sakhalin. Some straits of the reservoir act as a conditional border with the Sea of ​​Japan. Among the largest rivers flowing into the sea, it is worth noting the Amur, Bolshaya, Penzhina, Okhota.

Cities on the Sea of ​​Okhotsk

The main ports and cities of the Okhotsk water area include:

• Ayan, Okhotsk and Magadan on the mainland;
• Korsakov on Sakhalin Island;
• Severo-Kurilsk on the Kuril Islands.

Fisheries of the Sea of ​​Okhotsk

(Private fishing: fishing on the shores of the Sea of ​​Okhotsk, which is only allowed during the open fishing season, but certain species, such as crab, require a permit, otherwise it may be considered poaching)

The natural resources of this northern sea are very diverse. Fishing, production of salmon caviar and seafood are actively developing on the territory of the reservoir. Famous inhabitants of these regions are pink salmon, sockeye salmon, cod, chum salmon, coho salmon, flounder, chinook salmon, herring, crabs and squids, pollock, navaga. In addition, there is limited fur seal hunting in the Shantar Islands. Now also popular is the extraction of shellfish, sea urchins and kelp.

(Fishing boat in the Sea of ​​Okhotsk)

Industry in the Sea of ​​Okhotsk began to develop in the 90s. First of all, we are talking about ship repair factories and fish processing enterprises on Sakhalin. The development of hydrocarbon raw materials is also carried out in the Sakhalin region. Currently, 7 points with oil deposits have been discovered in the sea area, which began to be developed back in the 70s. last century.

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 the Kamchatka Peninsula. From the south and west, it is bounded by the coast of Hokkaido, the eastern coast of Sakhalin Island and the coast of the Asian mainland. The sea is significantly elongated from southwest to northeast within a spherical trapezoid with coordinates 43°43'–62°42' N. sh. and 135°10’–164°45′ E. e. The greatest length of the water area in this direction is 2463 km, and the width reaches 1500 km. The surface area of ​​the sea surface is 1603 thousand km2, the length of the coastline is 10460 km, and the total volume of sea water is 1316 thousand km3. According to its geographical position, it belongs to the marginal seas of the mixed continental-marginal type. The Sea of ​​Okhotsk is connected to the Pacific Ocean by the numerous straits of the Kuril Islands, and to the Sea of ​​Japan through the La Perouse Strait and through the Amur Estuary by the Nevelskoy and Tatar Straits. The average value of the sea depth is 821 m, and the largest is 3521 m (in the Kuril basin).

The main morphological zones in the bottom topography are: the shelf (the continental and insular shoals of Sakhalin Island), the continental slope, on which separate underwater elevations, depressions and islands stand out, and the deep-water basin. The shelf zone (0–200 m) is 180–250 km wide and occupies about 20% of the sea area. Wide and gentle, in the central part of the basin, the continental slope (200–2000 m) 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 elevations and depressions are distinguished, where the depths change dramatically (the uplift of the Academy of Sciences, the uplift of the Institute of Oceanology and the Deryugin Basin). The bottom of the deep-water Kuril Basin is a flat abyssal plain, and the Kuril Ridge is a natural threshold separating the sea basin from the ocean.

The Amur Estuary, Nevelskoy in the north and Laperouse in the south straits connect the Sea of ​​Okhotsk with the Sea of ​​Japan, and the numerous Kuril Straits with the Pacific Ocean. The chain of the Kuril Islands is separated from the island of Hokkaido by the Strait of Treason, and from the Kamchatka Peninsula by the First Kuril Strait. The straits connecting the Sea of ​​Okhotsk with the adjacent areas of the Sea of ​​Japan and the Pacific Ocean provide the possibility of water exchange between the 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 Islands, which stretch for about 1200 km, on the contrary, are deeper, and their total width is 500 km. The deepest are the Bussol (2318 m) and Krusenstern (1920 m) straits.

The northwestern coast of the Sea of ​​Okhotsk is practically devoid of large bays, while the northern coast is significantly indented. The Tauiskaya Bay protrudes into it, the coasts of which are indented with 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 lips. The Gizhiginskaya and Penzhinskaya bays are separated by the elevated Taigonos Peninsula. In the southwestern part of Shelikhov Bay, north of the Pyagin 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 outline and form small bays. On the Sea of ​​Okhotsk side, the largest bays are located near Iturup Island, which are deep-water and have a very intricately dissected bottom.

Quite a few mostly small rivers flow into the Sea of ​​Okhotsk, therefore, with a significant volume of its waters, the continental runoff is relatively small. It is equal to about 600 km3 per year, while about 65% of the flow comes from the Amur River. Other relatively large rivers - Penzhina, Okhota, Uda, Bolshaya (in Kamchatka) - bring much 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 mouth areas of large rivers.

The shores of the Sea of ​​Okhotsk in different regions belong to different geomorphological types. For the most part, these are abrasion shores altered by the sea, and only on the Kamchatka Peninsula and Sakhalin Island are accumulative shores found. In general, the sea is surrounded by high and steep shores. In the north and northwest, rocky ledges descend directly to the sea. The coasts along the Sakhalin Bay are low. 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 the shores of its northern part are somewhat elevated.

According to the features 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-argillaceous and partially clayey oozes; the distribution zone of hemipelagic and pelagic clays in the western, eastern and northern parts of the Sea of ​​Okhotsk; as well as the distribution zone of inequigranular sands, gravel sandstones 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 monsoon climate zone of temperate latitudes. A significant part of the sea in the west deeply protrudes into the mainland and lies relatively close to the cold pole of the Asian land, 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 of ​​Japan, from where a significant amount of heat enters it. However, the influence of cooling factors is stronger than warming factors, so the Sea of ​​Okhotsk is generally cold.

In the cold part of the year (from October to April), the Siberian anticyclone and the Aleutian low act on the sea. The influence of the latter extends mainly to the southeastern part of the sea. This distribution of large-scale baric systems causes strong persistent northwesterly and northerly winds, often reaching storm strength. 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 and winter, cyclones are predominantly of continental origin. They bring with them an increase in wind, sometimes a decrease in air temperature, but the weather remains clear and dry, as continental air comes from the cooled mainland. In March - April, large-scale baric fields are restructured, the Siberian anticyclone is destroyed, and the Hawaiian maximum is strengthened. As a result, during the warm season (from May to October), the Sea of ​​Okhotsk is under the influence of the Hawaiian maximum and the area of ​​low pressure located over Eastern Siberia. At the same time, weak southeasterly winds prevail over the sea. Their speed usually does not exceed 6–7 m/s. Most often, these winds are observed in June and July, although stronger northwesterly and northerly winds are sometimes observed in these months. In general, the Pacific (summer) monsoon is weaker than the Asian (winter) monsoon, since the horizontal pressure gradients are smoothed out in the warm season.

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 an increase in wind to a storm, which can last up to 5–8 days. The predominance of southeasterly 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.

Geographical position, large length along the meridian, monsoonal change of winds and good connection of the sea with the Pacific Ocean through the Kuril Straits are the main natural factors that most significantly affect 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 runoff of the Sea of ​​Okhotsk waters predominates, and in the upper layers of the northern part of the ridge, Pacific waters enter. In the deep layers, the inflow of Pacific waters prevails.

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

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

• surface water mass with spring, summer and autumn modifications. It is a thin heated layer 15–30 m thick, which limits the upper stability maximum, which is mainly determined by temperature;
• the Sea of ​​Okhotsk water mass is formed from surface water in winter and manifests itself in spring, summer, and autumn as a cold intermediate layer lying between 40–150 m horizons. This water mass is characterized by fairly uniform salinity (31–32‰) and different temperatures;
• the intermediate water mass is formed mainly due to the descent of water along the underwater slopes within the sea, ranging from 100–150 to 400–700 m, and is characterized by a temperature of 1.5°C and a salinity of 33.7‰. This water mass 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 the deep water of the northwestern part of the Pacific Ocean near the horizon of 2300 m. This water mass fills the basin from the horizon of 1350 m to the bottom and is characterized by a temperature of 1.85 ° C and a salinity of 34.7 change only slightly with depth.

The water temperature on the sea surface decreases from south to north. In winter, almost everywhere, the surface layers cool down to a freezing temperature of –1.5…–1.8°C. Only in the southeastern part of the sea does it stay 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 goes 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 diverse. In August, the waters adjacent to the island of Hokkaido are warmest (up to 18–19°C). In the central regions of the sea, the water temperature is 11–12°С. The coldest surface waters are observed near Iona Island, near Cape Pyagin and near the Kruzenshtern Strait. In these areas, the water temperature is kept in the range of 6-7°C. The formation of local centers of increased and decreased water temperature 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, the change in temperature with depth is 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°C, in the southern part of the sea and near the Kuril Straits, the water temperature drops from 2.5–3°C on the surface to 1–1.4°C at 300–400 m horizons and then gradually rises up to 1.9–2.4°С in the bottom layer.

In summer, surface waters are warmed up to a temperature of 10–12°С. 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 the horizons of 200–250 m it is 1.5–2°С. Further, the temperature of the water almost does not change to the bottom. In the southern and southeastern parts of the sea, along the Kuril Islands, the water temperature drops from 10–14°С at the surface to 3–8°С at the 25 m horizon, then to 1.6–2.4°С at the 100 m horizon. and up to 1.4–2°C near 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 in it is negative, and only near the Kuril Straits does it have 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 from season to season. Salinity increases in the eastern part, which is under the influence of Pacific waters, and decreases in the western part, which is desalinated by continental runoff. In the western part, 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 freshening, the salinity on the surface is 25‰ or less, and the thickness of the freshened layer is about 30–40 m.

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

In individual bays and straits, salinity 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 regions of the sea covered with ice. The density is somewhat less in the relatively warm Kuril region. In summer, the water density decreases, its lowest values ​​are confined to the zones of influence of coastal runoff, and the highest values ​​are observed in the 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 horizons. In summer, a noticeable density stratification of waters along the vertical is created, the density increases especially noticeably at horizons of 25–50 m, which is associated with the heating of waters in open areas and desalination near the coast.

Intense ice formation over most of the sea excites an enhanced thermohaline winter vertical circulation. At depths up to 250–300 m, it propagates to the bottom, and below it is prevented by the maximum stability that exists here. In areas with a rugged bottom topography, 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 water inflow through the Kuril Straits, characteristic features of the system of non-periodic currents of the Sea of ​​Okhotsk are formed. The main one is the cyclonic system of currents, covering almost the entire sea. It is due to the predominance of cyclonic circulation of the atmosphere over the sea and the adjacent part of the Pacific Ocean. In addition, stable anticyclonic gyres can be traced in the sea.

Strong currents bypass the sea along the coastline counterclockwise: the warm Kamchatka Current, the stable East Sakhalin Current and the fairly strong Soya Current.

And finally, one more feature of the water circulation in 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 near the western coast of Kamchatka (11–20 cm/s), in the Sakhalin Bay (30–45 cm/s), in the region of the Kuril Straits (15–40 cm/s), over the Kuril Basin (11 –20 cm/s) and during the Soya (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. The velocities of tidal currents range from a few centimeters to 4 m/s. Away from the coast, the current velocities are low - 5–10 cm/s. In straits, bays and off the coast, their speeds increase significantly. For example, in the Kuril Straits, current velocities reach 2–4 m/s.

In general, tidal 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 fluctuations in the level are also well developed here. They occur mainly during the passage of deep cyclones over the sea. Surge rises in the level reach 1.5–2 m. The largest surges are noted on the coast of Kamchatka and in the Gulf of Patience.

The significant size and great depths of the Sea of ​​Okhotsk, frequent and strong winds over it determine the development of large waves here. The sea is especially stormy in autumn, and in some 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 restless 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 ordinary years, the southern boundary of the relatively stable ice cover curves northward and runs from the La Perouse Strait to Cape Lopatka.
The extreme southern part of the sea never freezes. However, due to the winds, significant masses of ice are carried into it from the north, often accumulating near the Kuril Islands.

The ice cover in the Sea of ​​Okhotsk lasts for 6–7 months. Floating ice covers more than 75% of the sea surface. Close-packed ice in the northern part of the sea presents 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. Part of the ice from the Sea of ​​Okhotsk is carried into the ocean, where it breaks up and melts almost immediately.

The predicted hydrocarbon resources of the Sea of ​​Okhotsk are estimated at 6.56 billion tons of oil equivalent, the proven reserves are over 4 billion tons. The largest deposits are on the shelves (along the coast of Sakhalin Island, the Kamchatka Peninsula, the Khabarovsk Territory and the Magadan Region). The deposits of Sakhalin Island are the most studied. Exploration work on the shelf of the island began in the 70s. In the 20th century, by the end of the 1990s, seven large fields (6 oil and gas condensate and 1 gas condensate) and a small gas field in the Tatar Strait were discovered on the shelf of North-Eastern Sakhalin. The total gas reserves on the Sakhalin shelf are estimated at 3.5 trillion m3.

The flora and fauna are very diverse. In terms of stocks of commercial crab, the sea ranks first in the world. Salmon fish are of great value: chum salmon, pink salmon, coho salmon, chinook, sockeye - a source of red caviar. Intensive fishing is carried out for herring, pollock, flounder, cod, navaga, capelin, etc. Whales, seals, sea lions, fur seals live in the sea. The fishing of mollusks and sea urchins is gaining more and more interest. Various algae are ubiquitous in the littoral.
Due to the poor development of the adjacent 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 the Tauiskaya Bay in the northern part of the sea and the shelf areas of Sakhalin Island are subjected to the greatest anthropogenic load. About 23 tons of oil products enter the northern part of the sea annually, 70–80% of which comes from river runoff. Pollutants enter the Tauyskaya Bay from onshore industrial and municipal facilities, and the wastewater from Magadan enters 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 sewage from municipal facilities. The annual flow of oil products into the southwestern part of the sea is estimated at about 1.1 thousand tons, with 75–85% coming from river runoff.

Petroleum hydrocarbons enter the Sakhalin Bay mainly with the runoff of the Amur River, therefore, their maximum concentrations, as a rule, are noted 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 main part of petroleum hydrocarbons enters the marine environment. In connection with the reduction of work at the fish canning enterprises of 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 an 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 the 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 the Aniva Bay - are subjected to intense oil pollution in the spring-summer period by commercial and fishing fleets. On average, the content of petroleum hydrocarbons in the La Perouse Strait does not exceed the limit of permissible concentration. Aniva Bay is slightly more polluted. The highest level of pollution in this area was noted 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 the exploration and production of oil and gas on the shelf of the island, and until the end of the 1980s, it did not exceed the maximum permissible concentration.