The line of the Sea of ​​Okhotsk is 50-100 km. Sea of ​​Okhotsk

In winter, the temperature of the surface waters of the sea usually does not fall below the freezing point (at salinity values ​​of 31-33.5‰ this is -1.6- -1.8°C). In summer, the temperature of surface waters usually does not exceed 7-14°C. Its values ​​in different areas of the sea, both in summer and winter, are determined both by the depth of the place and by horizontal and vertical movements of water. In coastal shallow areas of the sea and in areas of warm currents, the water temperature is higher than in areas of strong tidal mixing, where relatively warm surface and cold subsurface waters mix, or along the coast of Sakhalin, where the cold East Sakhalin Current passes.

The southern part of the sea is under the influence of warm currents, and the surface water temperature along the Kuril Islands is higher than along the continent. However, in February-March, the influx of warm waters by the Soya Current weakens (the La Perouse Strait is clogged with ice transported from the north), and the temperature of the warm waters of the East Kamchatka Current invading the sea drops to 1°-2°C. But even so, the temperature of the surface waters of the southeastern part of the sea is several degrees higher than the temperature of the waters of the rest of the sea by 1-2°C.

Spring warming (from April-May) of surface waters everywhere leads to an increase in temperature values ​​and the disappearance of ice. The most warmed areas are the shelf areas and the southern part of the sea (up to 2 and 6°C, respectively).

The restructuring of the temperature field to the summer state is most noticeable in June. Areas of strong tidal mixing (for example, the entrance to Shelikhov Bay) remain the least heated.

The highest values ​​(on average about 14°C) of sea surface water temperatures were recorded in August. The water temperature is higher in areas of warm currents (for example, off the coast of Hokkaido) and off the coast (except for the coast of Sakhalin Island, where upwelling is observed) and lower in areas of tidal mixing. Due to the influence of warm and cold currents, the water temperature in the western (cold) and eastern (relatively warm) parts of the sea usually differs by several degrees.

Cooling of the surface waters of the sea begins in September. In October, the most noticeable decrease in temperature to 4°C in the northwestern part of the sea is due to the rise of deep waters. However, in most of the sea the temperature is still quite high (5.5 to 7.5 ° C). In November, there is a sharp decrease in surface water temperature. North of 54°N. the water temperature drops below 2°C.

The surface water temperature distribution in December remains the same with minor changes until spring. The lowest water temperature values ​​correspond to areas of polynyas, and the highest values ​​correspond to areas of influx of warm waters (the La Perouse Strait and the southeastern part of the sea) and rising waters (Kashevarov Bank).

The distribution of water temperature on the surface allows us to identify thermal fronts (Fig.).

Main thermal fronts of the Sea of ​​Okhotsk

Fronts form during ice-free periods and are most developed in late summer.

Thermal fronts of the sea have different origins: tidal mixing, at the boundaries of warm currents, river flow (especially from the Amur Estuary) and zones of rising subsurface waters. Fronts arise at the boundary of warm currents off the western coast of Kamchatka (warm current from the Pacific Ocean) and along Hokkaido (warm current from the Sea of ​​Japan). Fronts also form at the boundaries of zones of strong tides (Shelikhov Bay and the Shantar Islands area). The East Sakhalin coastal front is caused by the rise of cold subsurface waters during the southern winds of the summer monsoon. The front in the central part of the sea corresponds to the middle line of distribution of compacted ice in winter. Throughout the summer, in the area of ​​the Kashevarov Bank there is a zone of cold (less than 3°C) water.

In the western part of the deep-sea basin, an anticyclonic eddy is observed throughout the year. The reason for its existence is the invading jets of warm water of the Soya Current and the denser cold waters of the East Sakhalin Current. In winter, due to the weakening of the Soya current, the anticyclonic vortex weakens.

Distribution of water temperature at a horizon of 50 m

At a horizon of 50 m, the water temperature is usually close (in winter) or lower (in summer) to the surface temperature. In winter, the horizontal distribution of water temperature in areas of ice formation is similar to the surface distribution due to intense mixing of water up to a horizon of 50 m (and on the shelf to a depth of 100 m). Only in May, in most areas of the sea, except for zones of strong tidal mixing, the surface layer warms up and, thus, a cold subsurface layer appears deeper than it. In July, at a horizon of 50 m, water with a temperature of less than 0°C is observed only in the northwestern part of the sea. In September, water temperatures continue to rise. But, if in Shelikhov Bay it is about 3°C, near the Kuril Islands 4°C, then in most of the sea it is about 0°C.

Maximum water temperatures at a horizon of 50 m are usually observed in October. But already in November, the area of ​​water with a temperature of less than 1°C increases sharply.

Features of the water temperature field are:

Two tongues of relatively warm (more than 0°C) waters along the Kamchatka Peninsula and from the 4th Kuril Strait to Jonah Island;

Warm water zone in the southwestern part of the sea. In winter it narrows to a narrow strip along the island. Hokkaido, and in summer it occupies most of the deep-sea basin.

Distribution of water temperature at a horizon of 100 m

At the 100 m horizon, water of the cold subsurface layer is usually noted. Therefore, the lowest water temperature values ​​are typical for the coastal areas of the northwestern part of the sea, and the highest for the zone along the Kuril Islands and for the strip from the 4th Kuril Strait to the Kashevarov Bank.

Intra-annual changes in water temperature are similar to those noted for the 50 m horizon.

Distribution of water temperature at a horizon of 200 m

The peculiarity of this horizon is a sharp decrease in seasonal changes. But they (winter decrease and summer increase in water temperature) always exist. The cold subsurface layer at this and underlying horizons can be identified only in areas of intense tidal mixing (in particular, in the Kuril Straits and the adjacent part of the sea). The distribution of warm water, as at higher horizons, can be traced in two branches - along Kamchatka and from the 4th Kuril Strait to Jonah Island.

Distribution of water temperature at a horizon of 500 m

At the horizon of 500 m and deeper, there are no seasonal changes. At this horizon the average annual temperature is higher than at the sea surface. Deeper than this horizon, the water temperature continuously decreases.

Distribution of water temperature at a horizon of 1000 m

The maximum water temperature at a horizon of 1000 m is located near the Kruzenshtern Strait (2.44°C), through which, at this depth, the greatest transfer of warm waters to the Sea of ​​Okhotsk apparently occurs. The lowest water temperatures on this horizon (2.2°C) are observed not in the northern part of the sea, but in the southern part.

Water temperature fields at standard horizons are given below.

The Sea of ​​Okhotsk is one of the largest and deepest seas in Russia. Important sea routes connect Vladivostok with the northern regions of the Far East and the Kuril Islands. Large ports on the mainland coast are Magadan and Okhotsk; on the island of Sakhalin - Korsakov; on the Kuril Islands - Severo-Kurilsk.

The Sea of ​​Okhotsk was discovered by Russian explorers I. Yu. Moskvitin and V. D. Poyarkov in the first half of the 17th century. In 1733, work began on the Second Kamchatka Expedition, whose participants compiled detailed maps of almost all of its shores.

The Sea of ​​Okhotsk, also called the Lama or Kamchatka Sea, is a semi-enclosed sea in the northwestern part of the Pacific Ocean. It washes the shores of Russia and Japan (Hokkaido Island).

From the west it is limited by the continent of Asia from Cape Lazarev to the mouth of the Penzhina River; from the north - the Kamchatka Peninsula; from the east by the islands of the Kuril ridge and from the south by the islands of Hokkaido and Sakhalin.

The Sea of ​​Okhotsk is connected to the Pacific Ocean through the Kuril Straits system. There are more than 30 such straits and their total width is more than 500 kilometers. It communicates with the Sea of ​​Japan through the Nevelskoy and La Perouse straits.

Characteristics of the Sea of ​​Okhotsk

The sea is named after the Okhota River flowing into it. The area of ​​the Sea of ​​Okhotsk is 1,603,000 square kilometers. Its average depth is 1780 meters, with a maximum depth of 3916 meters. From north to south the sea stretches for 2445 kilometers, and from east to west for 1407 kilometers. The approximate volume of water contained in it is 1365 thousand cubic kilometers.

The coastline of the Sea of ​​Okhotsk is slightly indented. Its length is 10,460 kilometers. Its largest bays are considered to be: Shelikhov Bay, Sakhalin Bay, Udskaya Bay, Tauiskaya Bay and Academy Bay. The northern, northwestern and northeastern shores are high and rocky. At the confluence of large rivers (Amur, Uda, Okhota, Gizhiga, Penzhina), as well as in the west of Kamchatka, in the northern part of Sakhalin and Hokkaido, the banks are predominantly low-lying.

From October to May - June, the northern part of the sea is covered with ice. The southeastern part practically does not freeze. In winter, the water temperature at the sea surface ranges from −1.8 °C to 2.0 °C; in summer, the temperature rises to 10-18 °C.

The salinity of the surface waters of the Sea of ​​Okhotsk is 32.8–33.8 ppm, and the salinity of coastal waters usually does not exceed 30 ppm.

Climate of the Sea of ​​Okhotsk

The Sea of ​​Okhotsk is located in the monsoon climate zone of temperate latitudes. For most of the year, cold, dry winds blow from the mainland, cooling the northern half of the sea. From October to April, negative air temperatures and stable ice cover are observed here.

In the northeastern part of the sea, the average temperature in January - February ranges from - 14 to - 20 ° C. In the northern and western regions, the temperature varies from - 20 to - 24 ° C. In the southern and eastern parts of the sea, winter is much warmer from - 5 up to - 7° C.

Average temperatures in July and August, respectively, are 10-12 ° C; 11-14° C; 11-18° C. The annual amount of precipitation in different places of the Sea of ​​Okhotsk is also different. Thus, in the north, 300-500 mm of precipitation falls per year; in the west up to 600-800 mm; in the southern and southeastern parts of the sea - over 1000 mm.

In terms of the composition of organisms living in the Sea of ​​Okhotsk, it is more arctic in nature. Species of the temperate zone, due to the thermal effects of oceanic waters, are inhabited mainly in the southern and southeastern parts of the sea.

In coastal areas there are numerous settlements of mussels, littorinas and other mollusks, barnacles, sea urchins, and many crustaceans.

A rich invertebrate fauna has been discovered at the great depths of the Sea of ​​Okhotsk. Glass sponges, sea cucumbers, deep-sea corals, and decapod crustaceans live here.

The Sea of ​​Okhotsk is rich in fish. The most valuable salmon species are chum salmon, pink salmon, coho salmon, chinook salmon and sockeye salmon. Commercial fishing for herring, pollock, flounder, cod, navaga, capelin and smelt is carried out here.

The Sea of ​​Okhotsk is home to large mammals - whales, seals, sea lions and fur seals. There are many seabirds that organize noisy “bazaars” on the coasts.

The UN recognized the enclave of the Sea of ​​Okhotsk as part of the Russian shelf

Inessa Dotsenko

The UN Commission on the Limits of the Continental Shelf recognized the Sea of ​​Okhotsk enclave with an area of ​​52 thousand square kilometers as part of the Russian continental shelf.

According to ITAR-TASS, this was stated by the Minister of Natural Resources and Environment of the Russian Federation Sergei Donskoy.

We have officially received a document from the UN Commission on the Continental Shelf on the satisfaction of our application to recognize the enclave in the Sea of ​​Okhotsk as the Russian shelf. This has actually already taken place, so I would like to congratulate everyone on this,” he said.

The commission's decision, according to the minister, is unconditional and has no retroactive effect. Now the enclave is fully subject to Russian jurisdiction.

As ITAR-TASS reports, Donskoy also said that Russia’s application to expand the continental shelf in the Arctic will be ready this fall. The time for submitting the application to the UN Commission on the Limits of the Continental Shelf depends on how other countries’ claims to the enclave in the Arctic will be built.

All resources that will be discovered there will be extracted exclusively within the framework of Russian legislation,” Donskoy noted. He said that according to geologists, the total volume of hydrocarbons discovered in this area exceeds a billion tons.

Magadan Governor Vladimir Pecheny believes that recognition of the enclave in the middle of the Sea of ​​Okhotsk as part of the Russian continental shelf opens up new prospects for the economy of Kolyma and the entire Far East. First of all, it will relieve the region’s fishermen of numerous administrative barriers.

Firstly, fishing for fish, crab, and shellfish can be carried out freely anywhere in the Sea of ​​Okhotsk. No special permits from the border service will be required either when going to sea or upon returning. Secondly, when Russian territory is not only the 200-mile zone, but the entire sea, we will get rid of poaching by foreign fishermen in our waters. It will be easier to preserve the unique environment,” the press service of the regional government quotes Pecheny as saying.

Reference

In the center of the Sea of ​​Okhotsk there is an elongated enclave of considerable size. Previously, all of it was considered the “open sea”. Vessels of any state could move and fish freely on its territory. In November 2013, Russia managed to prove rights to 52 thousand square kilometers of water in the center of the Sea of ​​Okhotsk. For comparison, this is larger than the area of ​​Holland, Switzerland or Belgium. The center of the Sea of ​​Okhotsk ceased to be part of the World Ocean and became completely Russian. After approval at the UN session, the process of legally classifying the enclave as part of the Russian continental shelf can be considered completely completed.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The sea has predominantly natural boundaries and is only separated from the waters by conventional boundaries. The Sea of ​​Okhotsk is a fairly large and deep sea in our country. Its area is about 1603 thousand km2, the volume of water is 1318 thousand km3. The average depth of this sea is 821 m, the maximum depth is 3916 m. According to its characteristics, this sea is a marginal sea of ​​a mixed continental-marginal type.

There are few islands in the waters of the Sea of ​​Okhotsk, among which the largest is. The Kuril ridge consists of 30 different in size. Their location is seismically active. There are over 30 active and 70 extinct ones here. Zones of seismic activity can be located both on islands and under water. If the epicenter is under water, then huge ones rise.

The coastline of the Sea of ​​Okhotsk, despite its considerable length, is quite equal. There are many large bays along the coastline: Aniva, Terpeniya, Sakhalinsky, Academy, Tugursky, Ayan and Shelikhova. There are also several lips: Tauiskaya, Gizhiginskaya and Penzhinskaya.

Sea of ​​Okhotsk

The bottom represents a wide range of different underwater elevations. The northern part of the sea is located on a continental shelf, which is a continuation of the land. In the western zone of the sea there is a sandbank of Sakhalin, located near the island. In the east of the Sea of ​​Okhotsk is Kamchatka. Only a small part is located in the shelf zone. A significant part of the water expanses is located on the continental slope. The sea depth here varies from 200 m to 1500 m.

The southern edge of the sea is the deepest zone, the maximum depth here is more than 2500 m. This part of the sea is a kind of bed, which is located along the Kuril Islands. The southwestern part of the sea is characterized by deep depressions and slopes, which is not typical for the northeastern part.

In the central zone of the sea there are two hills: the Academy of Sciences of the USSR and the Institute of Oceanology. These hills divide the underwater sea space into 3 basins. The first basin is the northeastern depression of TINRO, which is located west of Kamchatka. This depression is characterized by shallow depths, about 850 m. The bottom has. The second basin is the Deryugin depression, located east of Sakhalin, the water depth here reaches 1700 m. The bottom is a plain, the edges of which are slightly raised. The third basin is the Kuril basin. It is the deepest (about 3300 m). is a plain that extends for 120 miles in the western part, and 600 miles in the northeastern part.

The Sea of ​​Okhotsk is influenced by. The main source of cold air is located in the west. This is due to the fact that the western part of the sea is strongly cut into the mainland and is located not far from the Asian pole of cold. From the east, the relatively high mountain ranges of Kamchatka impede the advance of warm Pacific waves. The greatest amount of heat comes from the waters of the Pacific Ocean and the Sea of ​​Japan through the southern and southeastern borders. But the influence of cold air masses dominates over warm air masses, so in general the Sea of ​​Okhotsk is quite harsh. The Sea of ​​Okhotsk is the coldest compared to the Sea of ​​Japan.

Sea of ​​Okhotsk

During the cold period (which lasts from October to April), the Siberian and Aleutian lows have a significant influence on the sea. As a result, winds from the northern and northwestern directions predominate in the vastness of the Sea of ​​Okhotsk. The power of these winds often reaches storm force. Particularly strong winds are observed in January and February. Their average speed is about 10 – 11 m/s.

In winter, the cold Asian monsoon contributes to a strong depression in the northern and northwestern parts of the sea. In January, when the temperature reaches its minimum limit, on average the air cools to – 20 – 25 °C in the northwestern part of the sea, to – 10 – 15 °C in the central part and to –5 – 6 °C in the southeastern part. The last zone is influenced by warm Pacific air.

In autumn and winter, the sea is influenced by continental influences. This leads to increased winds and, in some cases, colder temperatures. In general, it can be characterized as clear with reduced. These climatic features are influenced by cold Asian air. In April–May, the Siberian anticyclone ceases to operate, and the impact of the Honolulu maximum intensifies. In this regard, during the warm period, small southeast winds are observed, the speed of which rarely exceeds 6 - 7 m/s.

In summer, different temperatures are observed depending on. In August, the highest temperature is recorded in the southern part of the sea, it is +18°C. In the central part of the sea the temperature drops to 12 – 14°C. The northeast has the coldest summer, the average temperature does not exceed 10–10.5°C. During this period, the southern part of the sea is subject to numerous oceanic cyclones, due to which the wind strength increases, and storms rage for 5–8 days.

Sea of ​​Okhotsk

A large number of rivers carry their waters into the Sea of ​​Okhotsk, but they are all mostly small. In this regard, it is small, it is about 600 km 3 during the year. , Penzhina, Okhota, Bolshaya - the largest ones flowing into the Sea of ​​Okhotsk. Fresh waters have little impact on the sea. The waters of the Sea of ​​Japan and the Pacific Ocean are of great importance for the Sea of ​​Okhotsk.

Geographical location and boundaries of the Sea of ​​Okhotsk

The Sea of ​​Okhotsk is located in the northwestern part of the Pacific Ocean and, due to its geographical location, belongs to the type of marginal seas. It washes the shores 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 eastern coast of the island. Sakhalin and about. Hokkaido.

Geographical location of the Sea of ​​Okhotsk