Over the Pacific Ocean, they are formed under the influence of planetary factors that cover most of them. As well as over the Atlantic, on the sub tropical latitudes of both hemispheres above the ocean are the centers of constant baric maxima, at equatorial latitudes There is an equatorial depression, in the temperate and circumpolar regions there are areas of low pressure: in the north - the seasonal (winter) Aleutian minimum, in the south - part of the permanent Antarctic (more precisely, Antarctic) belt of low pressure. The formation of the Pacific Ocean climate is also influenced by the baric centers that form over the adjacent continents.
The thin line indicates three-month readings, and the thick line represents a simple 39-month running average. The thin line represents monthly values, while the thick line represents the simple 37-month average.
- Temperatures in degrees Celsius.
- Source: Global Maritime Argo Atlas.
Water color and transparency of the Pacific Ocean
Data source: National Center oceanographic data. Layout showing the Central Pacific Ocean with the locations of the measurement zones shown in the three diagrams below. The thin line indicates monthly values, and the thick line is the simple 7-year average. Annual Pacific Decadal Oscillation National Oceanic and Atmospheric Administration and University of Washington.
- Please cut for geographic location.
- Image source: A cooperative institute between Washington DC and the University.
Wind systems are formed according to the distribution atmospheric pressure over the ocean. Subtropical highs and equatorial depression determine the effect of trade winds in tropical latitudes. Due to the fact that the centers of the North Pacific and South Pacific highs are shifted towards the American continents, the highest speeds and stability of the trade winds are observed precisely in the eastern part of the The Pacific.
Mechanism 1 monitors sea level at many locations on a time scale ranging from several months to several years. As an example, many coastal stations exhibit pronounced annual fluctuations, reflecting seasonal variations in air pressure and wind speed. Long term climate change occurring over decades or centuries will also influence measurements of sea level changes.
Mechanism 2 - with the important exception of earthquakes and tsunamis - usually lasts for a long time and is not significant on human timescales. This may refer to changes in the propagation rate of the seabed, causing volume changes in mountain ranges the middle ocean and the slowly changing configuration of land and oceans. Another effect may be the slow rise of basins due to isostatic discharge by deglaciation after the ice age. Floor Baltic Sea and Hudson's Bay are currently growing, resulting in a slow, clean transfer of water from these basins to the adjacent oceans.
Southeastern winds hold here up to 80% of the time in an annual output, their prevailing speed is 6-15 m / s (maximum - up to 20 m / s). Northeastern winds have a slightly lower stability - up to 60-70%, their prevailing speed is 6-10 m / s. Trade winds rarely reach storm power.
The maximum wind speeds (up to 50 m / s) are associated with the passage of tropical cyclones - typhoons.
Slow changes in very large glaciers and movements in the mantle will affect the gravitational field and therefore the vertical position of the ocean surface. Any increase in the total mass of water, as well as the deposition of sediment in the oceans, increases the load on their bottom, creating a sinking in the viscoelastic flow in the mantle below. The flow of the mantle is directed towards the surrounding land area, which will increase, thereby partially offsetting the initial rise in sea level caused by the increase in water mass in the ocean.
Mechanism 3 only affects the very top of the oceans on human timescales. Typically, temperature changes in density are more important than changes caused by salinity. Sea water has a relatively small coefficient of expansion, but the effect should not be overlooked, especially when interpreting satellite altimetry data. Thermal expansion of the column sea water will not affect the total mass of water in the column under consideration and, therefore, will not affect the potential at the top of the water column.
The frequency of occurrence of tropical cyclones in the Pacific Ocean (according to L. S. Minina and N. A. Bezrukov, 1984)
Typhoons usually occur in the summer and start in several areas. The first area is located east of the Philippine Islands, from where tropical cyclones move in northwest and north directions towards East Asia and further northeast towards the Bering Sea. Annually hitting the Philippines, Japan, Taiwan, the east coast of China and some other areas, typhoons, accompanied by heavy rains, hurricane winds and storm waves up to 10-12 m high, cause significant destruction and lead to the death of thousands of people. Another area is located northeast of Australia in the New Hebrides area, from here typhoons move towards Australia and New Zealand. In the eastern part of the ocean, tropical cyclones are rare, and their origin is in coastal areas adjacent to Central America. The tracks of these hurricanes run through the coastal areas of California towards the Gulf of Alaska.
Thus, the expansion of ocean water with temperature regime will not lead to lateral displacement of water, but will only lead to a local rise of the ocean surface. Near the coast, where people live, the water depth approaches zero, so there will be no thermal expansion. Mechanism 3 is therefore not important for coastal regions.
Mechanism 4 is important factor for global sea level changes along coasts, for human time scales. Changes in the volume of floating glaciers — ice shelves — do not affect global sea level, just as changes in floating sea ice do not. Only the global balance of land or land glaciers is important for the global sea level along the coasts.
In the near-equatorial latitudes, in the convergence zone of the trade winds, weak and unstable winds prevail, calm weather is very characteristic. V temperate latitudes both hemispheres are dominated by westerly winds, especially in the southern part of the ocean. It is in the middle latitudes of the Southern Hemisphere that they have the greatest strength ("roaring forties") and constancy. Frequent cyclones at the polar front determine here the formation of storm winds with a speed of more than 16 m / s and a repeatability in the autumn-winter period of up to 40%. Directly off the coast of Antarctica in high latitudes, easterly winds prevail. In the temperate latitudes of the Northern Hemisphere, strong westerly winds of the winter period are replaced by weak ones in summer.
Wrap-up: Mechanisms 1 and 4 are the most important for understanding sea level changes along coasts. Pressure gauges are located directly on the coastal areas and record the net movement of the surface of the local ocean in relation to the earth. Local relative sea level change is what is important for coastal planning purposes, so tide data is directly applicable for planning purposes for coastal features. If one of them is known, the other component can be calculated.
To build time series of sea level measurements at each station, monthly and annual means must be reduced to a common reference. The blue dots are individual monthly observations and the purple line represents the current 121-month average. The bottom two panels show the annual sea level change calculated for time windows of 1 and 10 years, respectively. These values are displayed at the end of the interval in question. Last update charts: May 24.
North- Western part The Pacific Ocean is an area of pronounced monsoon circulation. The extremely powerful Asian maximum in winter forms here northerly and north-westerly winds, which carry cold and dry winds from the mainland. In summer, they are replaced by southerly and southeasterly winds, which carry warm and humid winds from the ocean to the mainland.
Air temperatures and precipitation
The great length of the Pacific Ocean in the meridional direction determines significant inter-latitudinal differences in thermal parameters at the water surface. The latitudinal zoning of heat distribution is clearly manifested over the ocean area.
Subsurface water body of the Pacific Ocean
Chart last updated: May 23. Holgate suggested that the nine stations listed on the chart capture the variability found at more stations over the past half century previously studied. For this reason the average values of the Holgate-9 calibration stations are of interest. The blue dots are individual monthly averages and the purple line represents the current 121-month average. Chart last updated: May 17th. Sea level from satellite altimetry.
Maximum high temperatures(up to 36-38 ° C) are recorded in the northern tropic region east of the Philippine Sea and in the region of the California and Mexican coasts. The lowest are in Antarctica (up to - 60 ° С).
The distribution of air temperature over the ocean is significantly influenced by the direction of the prevailing winds, as well as warm and cold ocean currents. In general, at low latitudes, the western part of the Pacific Ocean is warmer than the eastern one.
Bottom water masses of the Pacific Ocean
Satellite altimetry is a new and valuable type of measurement that provides a unique understanding of the detailed topography of the oceans' surface and how it changes. However, it is not an accurate tool for estimating changes in global sea level due to a number of assumptions made when interpreting the original satellite data.
One of the assumptions made when interpreting satellite altimetry data is the amount of correction made locally and regionally for lexical isostatic correction. This enormous mass transfer induces rimma changes in surface loading, leading to viscoelastic mantle flow and elastic effects in the upper crust.
The influence of the landmass of the continents surrounding the ocean is extremely great. The predominantly latitudinal course of the isotherms of any month is usually disturbed in the contact zones of the continents and the ocean, as well as under the influence of the prevailing air currents and ocean currents.
The influence of Antarctica is extremely important in the distribution of air temperature over the ocean. The air over the southern half of the ocean is colder than over the north. This is one of the manifestations of the polar asymmetry of the Earth.
The blue dots are individual observations and the purple line is the current 121-month average. Compare with the chart below. The thick lines show the average for the year. The difference between the two data is mainly due to the change in the zero reference level. Compare with the above diagram.
For loading the entire data series, as for reading the calibration information. to read about data smoothing. In the ocean, wind is the main culprit in creating these surface movements. The wind creates a current in surface waters Oh; this current is then modified by the shapes of the continents and the rotation of the Earth. Unless you spend a lot of time on the great oceans, you may not be familiar with global ocean circulation patterns, but sailors have known about them for centuries. You've probably heard of one of these big currents - the Gulf Stream - when you listen to weather reports.
Distribution atmospheric precipitation is also subject to a common latitudinal zoning.
The greatest amount of precipitation falls in the equatorial-tropical zone of convergence of trade winds - up to 3000 mm per year and more. They are especially abundant in its western part - in the region of the Sunda Islands, the Philippines and New Guinea, where powerful convection develops in the conditions of an unusually fragmented land. To the east of the Caroline Islands, annual precipitation exceeds 4800 mm. In the equatorial "zone of calm" precipitation is significantly less, and in the east, in near-equatorial latitudes, there is a relatively dry zone (less than 500 mm and even 250 mm per year). In temperate latitudes, annual precipitation amounts are significant and amount to 1000 mm or more in the west and up to 2000-3000 mm or more in the east of the ocean. The smallest amount of precipitation falls in the areas of action of subtropical baric maxima, especially along their eastern periphery, where downdrafts are most stable. In addition, cold ocean currents (California and Peruvian) pass here, contributing to the development of the inversion. So, to the west of the California Peninsula, less than 200 mm falls, and off the coast of Peru and northern Chile - less than 100 mm of precipitation per year, and in some areas above the Peruvian Current - 50-30 mm or less. At high latitudes of both hemispheres, due to weak evaporation in conditions low temperatures air precipitation is small - up to 500-300 mm per year or less.
The Gulf Stream is a key player in the global circulation of the ocean. He carries warm water from The Caribbean along the east coast of America, and then to Europe, warming up the climate in these areas. But global ocean circulation doesn't just happen on the surface. This is because ocean water has different densities.
The colder the water Density also depends on the salinity or salt content of the ocean water, water with more salt is denser and therefore heavier than water with less salt Thus, denser, heavier water sinks and less dense, lighter the water rises. To imagine the ocean moving, imagine a conveyor belt from the bottom of the ocean to the surface. But the beaches are at the very top of the ocean, the deepest part of the ocean measured so far is about 11 miles down!
The distribution of atmospheric precipitation in the intertropical convergence zone is usually uniform throughout the year. The same is observed in high pressure subtropical areas. In the area of the Aleutian baric minimum, they fall mainly in winter during the period of the greatest development of cyclonic activity. The winter maximum precipitation is also typical for the temperate and circumpolar latitudes of the South Pacific. In the monsoon northwestern region, the maximum precipitation occurs in the summer.
Deep water bodies of the Pacific Ocean
No matter how warm the ocean surface is, the ocean's sheer volume and deep basins keep the temperature at the ocean floor only slightly above freezing. So where does this cold water come from? Melting glaciers form cold water, which then sinks near the poles, pushing warm water up and around the world. The result is a complex 3D oceanic global circulation system based on the simple idea that colder, denser water sinks below warmer, less dense water.
Cloudiness over the Pacific Ocean in annual output reaches its maximum values in temperate latitudes. Fogs are most often formed there, especially over the water area adjacent to the Kuril and Aleutian Islands, where their frequency in summer is 30-40%. In winter, the likelihood of fog is sharply reduced. Fogs are not uncommon west coasts continents in tropical latitudes.
These movements mean that the world's oceans are "mixing", spreading nutrients and oxygen. You might think that deep sea volcanic activity would heat up deep ocean waters, and it does, but only marginally. The mid-ocean ridge system, which is actually a long line of submarine volcanoes, supports hydrothermal vents: deep sea hot springs. These vents erupt into the highly heated mineral water.
The really cool thing is that releasing this warm water allows living things to thrive in the ventilation fluid, but all that hot heat dissipates pretty quickly. Thus, the cold waters of the deep oceans cool the hot fluids of the vents very effectively. It's like being in a cold room with a fireplace, to stay warm you need to stay right in front of that fireplace! If you get too close to the fire, of course, you will sing your clothes and your eyebrows! They had to give up work for the whole day because the robotic arm got ready!
The Pacific Ocean is in all climatic zones, except for the arctic.
Physicochemical properties of waters
The Pacific Ocean is considered the warmest of the Earth's oceans. Its average annual surface water is 19.1 ° C (1.8 ° C higher than the temperature of the Atlantic Ocean and 1.5 ° C higher than the Indian Ocean). This is due to the huge volume of the water basin - the heat accumulator, large area water areas in the most heated equatorial-tropical regions (more than 50% of the total), the isolation of the Pacific Ocean from the cold Arctic basin. The influence of Antarctica in the Pacific Ocean is also weaker in comparison with the Atlantic and Indian oceans thanks to its huge area.
Clouds and pressure
To prevent these costly mistakes, pilots receive a lot of additional training. The co-pilot should receive additional training to the south, under the supervision of the main pilot. And Atlantis carries enough spare parts to rebuild the entire sub! When you're here, you can't just go to the store to pick up a new "widget"!
Dark, freezing, under pressure and away from the hardware store! He's sure he's breathing heavily in deep sea holes! But such an exciting - unknown world, below at the bottom of the sea. It provides a brief overview of the following topics: How water temperature and salt content alter the density of water. Why the water at the bottom of the ocean can be slightly above freezing when the surface waters are soft 80 °. How glaciers and deep sea volcanic activity affect the mix. ... Complement oceanography research with activities taken from this article on ocean circulation and deep sea temperatures.
The distribution of the temperature of the surface waters of the Pacific Ocean is mainly determined by heat exchange with the atmosphere and the circulation of water masses. V open ocean isotherms usually have a latitudinal course, with the exception of regions with meridional (or submeridional) water transport by currents. Particularly strong deviations from latitudinal zonality in the temperature distribution of ocean surface waters are observed in the western and east coasts, where the meridional (submeridional) flows close the main circulation circuits of the Pacific Ocean waters.
In the equatorial-tropical latitudes, the highest seasonal and annual water temperatures are observed - 25-29 ° С, and their maximum values (31-32 ° С) belong to the western regions of equatorial latitudes. In low latitudes, the western part of the ocean is 2-5 ° C warmer than the eastern one. In the areas of the California and Peruvian currents, the water temperature can be 12-15 ° C lower compared to coastal waters located at the same latitudes in the western part of the ocean. In the temperate and subpolar waters of the Northern Hemisphere, the western sector of the ocean, on the contrary, is colder than the eastern one by 3-7 ° С throughout the year. In summer, the water temperature in the Bering Strait is 5-6 ° C. In winter, the zero isotherm runs along the middle part of the Bering Sea. The minimum temperature here is up to -1.7-1.8 ° C. In Antarctic waters in areas where floating ice is spread, the water temperature rarely rises to 2-3 ° C. In winter, negative temperatures are noted south of 60-62 ° S. NS. In the temperate and subpolar latitudes of the southern part of the ocean, the isotherms have a smooth sublatitudinal course, a significant difference in water temperatures between the western and eastern parts there is no ocean here.
Salinity and density of waters
The distribution of the salinity of the Pacific Ocean waters obeys general laws. In general, this indicator at all depths is lower than in other oceans of the world, which is explained by the size of the ocean and the considerable distance central parts ocean from the arid regions of the continents. The ocean water balance is characterized by a significant excess of the amount of atmospheric precipitation together with the river runoff over the amount of evaporation. In addition, in the Pacific Ocean, in contrast to the Atlantic and Indian, at intermediate depths there is no inflow of especially saline waters of the Mediterranean and Red Sea types. The centers of the formation of highly saline waters on the surface of the Pacific Ocean are subtropical regions of both hemispheres, since evaporation here significantly exceeds the amount of precipitation.
Both highly saline zones (35.5% o in the north and 36.5% o in the south) are located above 20 ° latitude of both hemispheres. North of 40 ° N NS. salinity decreases especially quickly. At the top of the Gulf of Alaska, it is 30-31% o. V Southern hemisphere the decrease in salinity from the subtropics to the south slows down due to the influence of the current of the West Winds: up to 60 ° S. NS. it remains more than 34% o, while off the coast of Antarctica it decreases to 33% o. Water freshening is also observed in equatorial-tropical regions with a large amount of atmospheric precipitation. Between the centers of salinization and freshening of waters, the distribution of salinity is strongly influenced by currents. Along the shores, the currents carry freshened waters from high latitudes to lower latitudes in the east of the ocean, and saline waters in the west in the opposite direction. Thus, the isohaline maps clearly show the "tongues" of freshened waters that come from the California and Peruvian currents.
The most general pattern of changes in the density of waters in the Pacific Ocean is an increase in its values from the equatorial-tropical zones to high latitudes. Consequently, the decrease in temperature from the equator to the poles completely covers the decrease in salinity throughout the entire space from the tropics to high latitudes.
Ice formation in the Pacific Ocean occurs in the Antarctic regions, as well as in the Bering, Okhotsk and Japanese seas(partly in the Yellow Sea, bays of the eastern coast of Kamchatka and Hokkaido Island, and in the Gulf of Alaska). The distribution of ice mass across the hemispheres is very uneven. Its main share is in the Antarctic region. In the north of the ocean, the overwhelming majority of the floating ice formed in winter melts by the end of summer. The fast ice does not reach a significant thickness during the winter and also collapses in the summer. In the northern part of the ocean, the maximum age of ice is 4-6 months. During this time, it reaches a thickness of 1-1.5 m. southern border floating ice was noted off the coast of about. Hokkaido at 40 ° N. sh., and y east coast the Gulf of Alaska - at 50 ° N. NS.
The average position of the ice boundary is over the continental slope. The southern deep-water part of the Bering Sea never freezes, although it is located significantly north of the freezing regions of the Japanese and Sea of Okhotsk... The removal of ice from the Arctic Ocean is practically absent. On the contrary, in summer, part of the ice is carried out from the Bering Sea to the Chukchi Sea. In the north of the Gulf of Alaska, several coastal glaciers (Malaspina) are known to produce small icebergs. Usually, ice in the northern part of the ocean is not a major obstacle to ocean shipping. Only in some years, under the influence of winds and currents, ice "plugs" are created, which close the navigable straits (Tatarsky, La Perouse, etc.).
In the southern part of the ocean, large masses of ice are present all year round, and all types of it spread far to the north. Even in summer, the edge of the floating ice is kept at an average of about 70 ° S. sh., and in some winters with especially harsh conditions, ice spreads to 56-60 ° S. NS.
The thickness of the floating sea ice by the end of winter reaches 1.2-1.8 m. It does not have time to grow anymore, since it is carried out by currents to the north into warmer waters and collapses. There are no perennial pack ice in Antarctica. The powerful ice sheets of Antarctica give rise to numerous icebergs, which reach 46-50 ° S. NS. Farthest to the north, they are carried in the eastern part of the Pacific Ocean, where individual icebergs were found almost at 40 ° S. NS. The average size of Antarctic icebergs is 2-3 km in length and 1-1.5 km in width. The record size is 400 × 100 km. The height of the above-water part ranges from 10-15 m to 60-100 m. The main areas of the emergence of icebergs are the Ross and Amundsen Seas with their large ice shelves.
The processes of ice formation and melting are an important factor in the hydrological regime of water masses in the high-latitude regions of the Pacific Ocean.
Dynamics of waters
The features of circulation over the water area and adjacent parts of the continents primarily determine the general pattern of surface currents in the Pacific Ocean. Similar and genetically related circulation systems are formed in the atmosphere and ocean.
As in the Atlantic, the northern and southern subtropical anticyclonic currents and cyclonic circuits in the northern temperate latitudes are formed in the Pacific Ocean. But unlike other oceans, there is a powerful stable inter-trade countercurrent, which forms two narrow tropical circuits in the equatorial latitudes with the North and South trade currents: the northern one is cyclonic and the southern one is anticyclonic. Off the coast of Antarctica, under the influence of winds with an eastern component blowing from the mainland, the Antarctic Current is formed. It interacts with the current of the West Winds, and here another cyclonic circulation is formed, which is especially pronounced in the Ross Sea. Thus, in the Pacific Ocean, in comparison with other oceans, the dynamic system of surface waters is most pronounced. Zones of convergence and divergence of water masses are associated with circuits.
On the western shores of the Northern and South America in tropical latitudes, where the discharge of surface waters by the California and Peruvian currents is enhanced by steady winds along the coast, upwelling is most pronounced.
An important role in the circulation of the waters of the Pacific Ocean belongs to the Cromwell subsurface current, which is a powerful stream moving under the South Trade Wind at a depth of 50-100 m or more from west to east and compensating for the loss of water driven by trade winds in the eastern part of the ocean.
The length of the current is about 7000 km, the width is about 300 km, the speed is from 1.8 to 3.5 km / h. The average speed of most of the main surface currents is 1-2 km / h, the Kuroshio and Peruvian currents are up to 3 km / h. m 3 / s (for comparison, the California current - 10-12 million m 3 / s).
The tides in most of the Pacific Ocean are irregular semidiurnal. In the southern part of the ocean, tides of the correct semi-diurnal character prevail. Small areas in the equatorial and northern part of the water area have diurnal tides.
The height of tidal waves is on average 1-2 m, in the bays of the Gulf of Alaska - 5-7 m, in Cook Bay - up to 12 m. Highest height tides in the Pacific Ocean were recorded in the Penzhinskaya Bay (Sea of Okhotsk) - more than 13 m.
The Pacific Ocean has the highest wind waves(up to 34 m). The most stormy zones are 40-50 ° N. NS. and 40-60 ° S. sh., where the height of the waves with strong and prolonged winds reaches 15-20 m.
Storm activity is most intense in the area between Antarctica and New Zealand. In tropical latitudes, the prevailing waves are due to trade winds, it is quite stable in the direction and height of the waves - up to 2-4 m.Despite the huge wind speed in typhoons, the wave height in them does not exceed 10-15 m (since the radius and duration of these tropical cyclones are small ).
The islands and coasts of Eurasia in the northern and northwestern parts of the ocean, as well as the shores of South America, are often visited by tsunamis, which have repeatedly caused severe destruction and human casualties here.
Average temperatures
The Pacific Ocean is considered the warmest of the Earth's oceans. The average annual temperature of its surface waters is 19.1 ° C (1.8 ° C higher than the temperature Atlantic Ocean and by 1.5 ° C - the Indian Ocean). This is explained by the huge volume of the water basin - the heat accumulator, the large area of the water area in the most heated equatorial-tropical regions (more than 50% of the total), the isolation of the Pacific Ocean from the cold Arctic basin. The influence of the Antarctic in the Pacific Ocean is also weaker in comparison with the Atlantic and Indian Oceans due to its huge area.
The distribution of the temperature of the surface waters of the Pacific Ocean is mainly determined by heat exchange with the atmosphere and the circulation of water masses. In the open ocean, isotherms usually have a latitudinal course, with the exception of regions with meridional (or submeridional) water transport by currents. Particularly strong deviations from latitudinal zoning in the distribution of ocean surface water temperatures are observed near the western and eastern coasts, where meridional (submeridional) flows close the main circulation circuits of the Pacific Ocean waters.
In the equatorial-tropical latitudes, the highest seasonal and annual water temperatures are observed - 25-29 ° С, and their maximum values (31-32 ° С) belong to the western regions of equatorial latitudes. In low latitudes, the western part of the ocean is 2-5 ° C warmer than the eastern one. In the areas of the California and Peruvian currents, the water temperature can be 12-15 ° C lower compared to coastal waters located at the same latitudes in the western part of the ocean. In the temperate and subpolar waters of the Northern Hemisphere, the western sector of the ocean, on the contrary, is colder than the eastern one by 3-7 ° С throughout the year. In summer, the water temperature in the Bering Strait is 5-6 ° C. In winter, the zero isotherm runs along the middle part of the Bering Sea. The minimum temperature here is up to -1.7-1.8 ° C. In Antarctic waters in areas where floating ice is spread, the water temperature rarely rises to 2-3 ° C. In winter, negative temperatures are noted south of 60-62 ° S. NS. In the temperate and subpolar latitudes of the southern part of the ocean, the isotherms have a smooth sublatitudinal course; there is no significant difference in water temperatures between the western and eastern parts of the ocean.
Salinity and density
The distribution of the salinity of the Pacific Ocean waters obeys general laws. In general, this indicator at all depths is lower than in other oceans of the world, which is explained by the size of the ocean and the significant remoteness of the central parts of the ocean from the arid regions of the continents (Fig. 4).
The ocean water balance is characterized by a significant excess of the amount of atmospheric precipitation together with the river runoff over the amount of evaporation. In addition, in the Pacific Ocean, in contrast to the Atlantic and Indian, at intermediate depths there is no inflow of especially saline waters of the Mediterranean and Red Sea types. The centers of the formation of highly saline waters on the surface of the Pacific Ocean are subtropical regions of both hemispheres, since evaporation here significantly exceeds the amount of precipitation.
Both highly saline zones (35.5 ‰ in the north and 36.5 ‰ in the south) are located above 20 ° latitude of both hemispheres. North of 40 ° N NS. salinity decreases especially quickly. At the top of the Gulf of Alaska, it is 30-31 ‰. In the Southern Hemisphere, the decrease in salinity from the subtropics to the south slows down due to the influence of the current of the West Winds: up to 60 ° S. NS. it remains more than 34% o, while off the coast of Antarctica it decreases to 33% o. Water freshening is also observed in equatorial-tropical regions with a large amount of atmospheric precipitation. Between the centers of salinization and freshening of waters, the distribution of salinity is strongly influenced by currents. Along the shores, the currents carry freshened waters from high latitudes to lower latitudes in the east of the ocean, and saline waters in the west in the opposite direction.
Rice. 4. Average annual salinity at the ocean surface
The most general pattern of changes in the density of waters in the Pacific Ocean is an increase in its values from the equatorial-tropical zones to high latitudes. Consequently, the decrease in temperature from the equator to the poles completely covers the decrease in salinity throughout the entire space from the tropics to high latitudes.
