Vertical structure of the waters of the World Ocean. World Ocean and its parts
Hydrological structure of the World Ocean Largely determines the distribution of the organic world. The properties of oceanic waters and the features of circulation make it possible to divide the aqueous masses on surface, intermediate, deep and donon.Surface water due to high stirring is homogeneous, the thickness of their layer due to the features of heat exchange changes markedly for the seasons and, depending on the geographical latitude of the area. Usually, the bottom limit of surface waters takes depth on which the amplitude of the annual temperature move is almost indistinguishable. On average, it is located at a depth of 200-300 m, in the areas of cyclonic circulation and divergences, it is raised to 150-200 m, and in the areas of anti-cyclonic cycles and convergence, it is lowered to 300-400 m. In the latitudinal direction, surface water is divided into equatorial, tropical, subogenous and polar. The first are characterized by the highest temperature, low salinity and density, complex circulation. For tropical waters is characterized by high salinity and density. Subolar waters in different oceans are quite variable in their characteristics. Polar waters are distinguished by negative temperatures (-1.2-1.5 °), low salinity (32.5-34.6% o), are formed above the Arctic and Antarctic fronts.
Intermediate waters occur under surface to depth 1000-1200 m. The maximum thickness of their layer reaches the polar regions and the central areas of anti-cyclonic circulation in the equatorial zone, where water is raised, the thickness of the intermediate water layer is reduced to 600-900 m.
Antarctic intermediate waters are formed as a result of the activities of the Antarctic circumpolar flow. The movement of the bottom waters in the southern direction is compensated by the outflow to the north of deep and surface water. Next to the north, Antarctic components are gradually transformed, and these waters return to Antarctic latitudes in the form of circumpolar deep water. They contain a noticeable admixture of relatively more saline deep water from the South Atlantic. During the east, these aqueous masses are fully included in the circumpolar circulation. About 55-60% are the Antarctic surface water, the rest is the Antarctic Dutton Water. Circumpolar deep water bring a large amount of heat to the Antarctic seas, where it is spent on the heating of cold waters and the atmosphere. Antarctic surface waters are traced to zone between 50 ° and 60 °. The contact zone between the two surface water masses is known as the Antarctic convergence zone.
The depths of water are formed in high latitudes as a result of mixing surface and intermediate waters. They are homogeneous and stretch to the depths of 3000-4000 m.
The most powerful flow in the World Ocean is the Antarctic circumpolar flow (the flow of Western winds). It drifts along the coast of Antarctica, crossing three oceans by moving every second more than 250 million m3 of sea water. Its length is up to 30 thousand km, width - 1000-1500 km, depth from 2 to 3 km. The speed in the upper layers reaches 2 km / h.
Dutton waters are also formed due to lowering overlaid waters mainly in high latitudes.
The whole thickness of the ocean water is in a continuous movement, which is excited by thermogaline (heating, cooling, precipitation, evaporation) and mechanical factors (tangent wind voltage, atmospheric pressure), as well as faded forces.
The overall scheme of the occurrence of flows (Fig. 5) in the ocean is mainly determined by the nature of the atmosphere circulation and the geographical location of the continents. Separate the system of horizontal and vertical flows.
In the tropical wind zone (Passat) blowing with a large constancy and force from the east to the west, and only near the equator there is a pole zone. Accordingly, the Ocean is formed by the Northern and South Passatowns, and between them - the oppositely directed (from the west to the East) interpassate current. Passat winds create an equatorial flow running from east to west. Having met the mainland barrier, it turns in the northern hemisphere - to the right, in South - to the left. On both sides of the equator, annular flows are formed, directed in the northern hemisphere clockwise, in South - counterclockwise.
Fig. 5. Scheme of the formation of flows (by A.S. Konstantinov, 1986)
In the northern and southern moderate zones, Western winds dominate, and in high latitudes - oriental. Under their impact, flows arise, the multidimension of which leads to the formation of the giant cyphans of the ocean water. North of the equator is the area of \u200b\u200bthe northern tropical cycle (counterclockwise), then - subtropical (clockwise) subarctic (counterclockwise). In the southern hemisphere there are three similar coupling, but with a different direction of rotation. The circulation under consideration determines the East-Western Asymmetry of the temperature field of the ocean and determines the spread of marine organisms.
Life in the entire World Ocean directly depends on the Antarctic Circle of Continental Test (ACC), raising deep water to the surface of nutrients. Research results give reason to believe that marine life must have greater sensitivity to climate change, which was thought before - after all, according to the majority of climate change models, the ocean circulation should change. Although the oceanographers singled out several directions of ocean circulation, a new study conducted in Princeton University showed that three quarters of all biological activity in the oceans depends only on ACS. According to calculations, when changing this circulation, the biological productivity of all oceans will fall four times.
In addition to surface flows, in the World Ocean there is a complex system of depth. Dutton waters that fill the depths of the oceans are mainly formed on the shelf of Antarctica. Here, as a result of ice formation, the salinity of water rises, and it (as more dense) immersed on the bottom and moves to the north. The influx of well-aerated antarctic water supplies oxygen depth of oceans, providing existence of life here.
The Atlantic cod migrates between the spawns located south of Iceland and the food areas along the East Greenland flow.
The rate of depth flows can reach 10-20 cm / s, i.e., commensurate with the average speeds of surface flows. This is fair in relation to both the mid-profile flows and the bottom flows.
Vertical movements of water can be caused by a change in the density of the water layers located above each other, immersing it in the windward shore and lifting in the leeward, due to the passage of cyclones and anticyclones. Each immersion of the aquatic mass corresponds to the compensatory water lift elsewhere. The areas of convergence (designers) of the aquatic masses are distinguished, where the surface waters are immersed in depth, and divergence areas (discrepancies), where the depths of water come to the surface.
Together with deep waters, nitrogen and phosphorus compounds rose to the surface, this leads to the rapid development of phytoplankton in the Area zones. Phytoplankton eat wraps serving fish feed. Therefore, it is usually more fish here than in other areas of the ocean.
The surface of the ocean has a complex dynamic relief, whose features are interrelated with water circulation. The divergences dedicated to the hollows of the dynamic relief in the central parts of cyclonic circulation, in the field of drift flows, approximately coincide with the areas of the waters and their lifting from the depths - an appellaling (Fig. 6). Convergences dedicated to the ridges of dynamic relief in the central parts of anti-cyclonic circulation, in the region of drift flows, approximately coincide with the regions of the heat of the waters and lowering the depth - downwear.
Waves are mostly important in the ocean hydrodynamics, which are mainly caused by the wind and the action of tidal forces, which simultaneously determine the occurrence of tidal and tidy flows (Fig. 7). Distinguish semi-duct, daily and mixed tides.
In the world ocean, the functioning of the hydrological link goes in two mutually opposite directions: on the one hand, it is aimed at the formation of a relatively stable dynamic structure of the ocean - the separation of water masses, passion
Fig. 7. Dynamics of tidal wave on about. Sakhalin (by: Atlas, 2002)
The fiction of its water, and on the other, to the destruction of these structures, the leveling of gradients of the physicochemical properties of sea water.
Hydrological structures due to the inertia of the aqueous medium have relative resistance over time, have natural boundaries, which makes their role in the physico-geographical differentiation of the World Ocean, especially significant. However, due to water mobility, scale ecosystems can be destroyed, having spontaneous blurry boundaries. The result of the functioning of the hydrological level of the World Ocean is the streamlining of hydroclimatic conditions.
Ocean water is a solution in which all chemical elements are contained. Mineralization of water is called her saltness . It is measured in thousands of thousands, in ppm and is indicated. The average salinity of the oceans is 34.7 ‰ (rounded 35). In one ton of ocean water, 35 kg of salts are contained, and their total amount is so large that if removing all the salts and evenly distribute them over the surface of the mainland, then a layer of 135 m would be formed.
Ocean water can be considered as a liquid multi-element ore. It produces table salt, potash salts, magnesium, bromine, and many other elements and connections.
Mineralization of water is an indispensable condition for the origin of life in the ocean. It is marine waters that are optimal for most forms of living organisms.
The question of which was the salinity of water at the dawn of life, in which water the organic substance arose, is solved relatively uniquely. Water, standing out from the mantle, captured and transported the moving components of the magma, and primarily salt. Therefore, the primary oceans were sufficiently mineralized. On the other hand, photosynthesis decomposes and only pure water is seized. Consequently, the salinity of the oceans is steadily rising. These historical geology suggests that Archeye's reservoirs were straly than 10-25, their salinity was salon.
52. Penetration of light into water. Transparency and sea of \u200b\u200bsea
Penetration of light in the water depends on its transparency. Transparency is expressed by the number of meters, that is, a depth on which a white disc is still visible with a diameter of 30 cm. The greatest transparency (67 m) was observed in 1971 in the central part of the Pacific Ocean. The transparency of Sargassov Sea is close to it - 62 m (by a disk with a diameter of 30 cm). Other water areas with clean and transparent water are also located in the tropics and subtropics: in the Mediterranean Sea - 60 m, in the Indian Ocean - 50 m. High transparency of tropical waters is due to the characteristics of the circulation of water in them. In the seas, where the amount of suspended particles increases, transparency decreases. In the North Sea, it is equal to 23 m, in the Baltic - 13 m, in white - 9 m, in Azov - 3 m.
Water transparency has high ecological, biological and geographical importance: vegetation of phytoplankton is possible only to the depths that sunlight penetrates. For photosynthesis, a relatively much light is required, so with depths of 100-150 m, rarely 200 m plants disappear. The lower limit of photosynthesis in the Mediterranean Sea is at a depth of 150 m, in the North Sea - 45 m, in the Baltic Sea - only 20 m.
53. World Ocean Structure
The structure of the world's ocean is its structure - vertical stratification of water, horizontal (geographical) explanation, character of aquatic mass and oceanic fronts.
Vertical stratification of the World Ocean.In the vertical section, the thickness of the water decays into large layers, similar to the layers of the atmosphere. They are also called spheres. The following four spheres (layers) are distinguished:
Upper sphere It is formed by direct metabolism and a substance with a troposphere in the form of microcirculation systems. It covers a layer of 200-300 m. This upper sphere is characterized by intense stirring, light penetration and significant temperature fluctuations.
Upper sphere Disintegrates the following private layers:
a) the topmost layer with a thickness of several tens of centimeters;
b) wind exposure layer 10-40 cm deep; He participates in the excitement, reacts to the weather;
c) a layer of a leap of temperatures in which it drops sharply from the upper heated to the lower, not affected by the excitement and not a heated layer;
d) layer of penetration of seasonal circulation and temperature variability.
Ocean flows usually capture the aquatic masses of only the upper sphere.
Intermediate sphere extends to the depths of 1,500 - 2000 m; Its water is formed from surface waters when they are lowering. At the same time, they are cooled and compacted, and then mixed in horizontal directions, mainly with the zonal component. Horizontal transfer of water masses prevail.
Deep sphere Does not reach the bottom of about 1,000 m. This sphere is characterized by a certain homogeneity. Its capacity is about 2,000 m and it concentrates more than 50% of the entire water of the world's ocean.
Dinner sphere It occupies the lowest layer of the ocean strata and extends to a distance of about 1,000 m from the bottom. The water of this sphere is formed in cold belts, in the Arctic and Antarctic and move on huge spaces on deep babins and gutters. They perceive heat from the bowels of the earth and interact with the bottom of the ocean. Therefore, with its movement, they are significantly transformed.
Water masses and ocean fronts of the upper sphere of the ocean.The water mass is called a relatively large volume of water, which is formed in a specific water area of \u200b\u200bthe world ocean and possessing for a long time almost constant physical (temperature, light), chemical (gases) and biological (plankton) properties. The aqueous mass moves as a whole. One mass of the other is separated by the ocean front.
The following types of water masses are distinguished:
1. Equatorial water masses Limited by equatorial and subequatorial fronts. They are characterized by the highest temperature in the open ocean, low salinity (up to 34-32), minimal density, large oxygen content and phosphates.
2. Tropical and subtropical water masses Created in areas of tropical atmospheric anticyclones and are limited from moderate belts with tropical northern and tropical southern fronts, and subtropical - the northern moderate and northern southern fronts. They are characterized by increased salinity (up to 37 ‰ or more), large transparency, poverty with nutritional salts and plankton. In environmental respect, tropical aquatic masses are ocean deserts.
3. Moderate aquatic masses Located in moderate latitudes and are limited from the poles of the Arctic and Antarctic fronts. They are distinguished by large variability of properties both in geographic latitudes and by season of the year. For moderate water masses, an intensive exchange of heat and moisture with the atmosphere is characterized.
4. Polar water masses The Arctic and Antarctic are characterized by the lowest temperature, the greatest density, increased oxygen content. Antarctic water is intensively immersed in the bottomhosphere and supply it with oxygen.
Ocean flows. In accordance with the zonal distribution of solar energy over the surface of the planet, both in the ocean and atmosphere are created by the same type and genetically related circulation systems. The old provision that ocean flows are caused exclusively by the winds are not confirmed by the latest research. Moving and aquatic, and air masses are determined by the total for the atmosphere and hydrosphere zonality: uneven heating and cooling of the ground surface. From this in some districts there are ascending currents and loss of mass, in others - downward currents and an increase in mass (air or water). Thus, the impulse of movement is born. Mass transfer is to adapt them to the gravity force, the desire for uniform distribution.
Most macrocirculation systems keep all year. Only in the northern part of the Indian ocean the flow changes after the monscons.
There are 10 large circulation systems on Earth:
1) North Atlantic (Azore) system;
2) Severoticookean (Hawaiian) system;
3) the Southatic System;
4) South-cooled system;
5) inventory system;
6) Equatorial system;
7) Atlantic (Icelandic) system;
8) Pacific (Aleutskaya) system;
9) Indian monsoon system;
10) Antarctic and Arctic system.
The main circulation systems coincide with the centers of the atmosphere. This commonality is genetic.
The surface flow deviates from the direction of the wind at an angle to 45 0 to the right in the northern hemisphere and left in the southern hemisphere. Thus, the trade-off flows go from the east to the west, the trade winds are shown from the northeast in the northern hemisphere and from the south-east in the southern hemisphere. The upper layer can follow the wind. However, each underlying layer continues to deviate to the right (left) from the direction of movement of the overlying layer. The flow rate is reduced. At some depth, the course takes the opposite direction, which practically means its termination. Numerous measurements have shown that flows ends at depths of no more than 300 m.
In the geographical shell as a system higher than the oceanosphere, levels - ocean flows are not only water flows, but also the transfer of air mass transfer, the direction of metabolicism and energy, the path of migration of animals and plants.
Tropical anticyclonic systems of ocean flows are the largest. They extend from one side of the ocean to another 6-7 thousand km in the Atlantic Ocean and 14-15 thousand km in the Pacific Ocean, and on the meridian from the equator to 40 ° latitude, by 4-5 thousand km. Sustainable and powerful flows, especially in the northern hemisphere, are mainly closed.
As in tropical atmospheric anticyclones, the movement of water goes clockwise in the north and counterclockwise in the southern hemisphere. From the eastern coast of the oceans (Western coast of the mainland), surface water refers to the equator, it rises from depth (divergence) and compensatively comes from moderate latitudes cold. So the cold flows are formed:
Canary cold flow;
California cold current;
Peruvian cold flow;
Bengelege cold flow;
West Western Cold Flow and DR.
The speed of flows is relatively small and is about 10 cm / s.
The jet of compensation flows are poured into the Northern and South Trading (Equatorial) warm currents. The speed of these flows is quite large enough: 25-50 cm / s on tropical periphery and up to 150-200 cm / sec close to the equator.
Approaching the banks of the continents, the trade-mounted flows, naturally deviate. Form large waste flows:
Brazilian current;
Gwiank current;
Antillest current;
East avian current;
Madagascar flow and others.
The speed of these flows is about 75-100 cm / s.
Due to the rejection effect of the Earth's rotation, the center of the anticyclonic flow system is shifted to the West relative to the center of the atmospheric anticyclone. Therefore, the transfer of water masses in moderate latitudes is concentrated in narrow bands from the western coast of the oceans.
Gwiank and Antillese Washed the Antilles and most of the water enters the Mexican bay. It begins the Golf Stream. The initial portion in the Floridian Strait is called Floridian flowThe depth of which is about 700 m, the width is 75 km, the capacity is 25 million m 3 / s. The water temperature here reaches 26 0 C. Reaching average latitudes, the aqueous masses are partially returned to the same system in the western banks of the mainland, partially involved in the cyclonic systems of the moderate belt.
The equatorial system is represented by an equatorial countercurring. Equatorial countercover It is formed as compensatory between trade in the flows.
Cyclonic systems of moderate latitudes are different in the north and southern hemispheres and depend on the location of the mainland. Northern cyclonic systems - Icelandic and Aleutskaya - Very extensive: from west to east, they are stretched by 5-6 thousand km and from north to south about 2 thousand km. The circulation system in the North Atlantic begins the warmthorthystream. It is often maintained by the name of the initial Golfstream. However, the actual Golf Stream as the stock continues for no further than the New Foundland Bank. Starting from 40 0 \u200b\u200bS.Sh. Water masses are involved in the circulation of moderate latitudes and under the influence of Western transfer and the coriolism force from the shores of America are sent to Europe. Due to the active water exchange with the Arctic Ocean, the North Atlantic flow penetrates into polar latitudes, where cyclonic activity forms several course cycling Irminger, Norwegian, Svalbard, Nordskapskoe.
Golfustrim the narrow sense is called the stock from the Gulf of Mexico to 40 0 \u200b\u200bS.Sh., in a broad sense - the flow system in the North Atlantic and the western part of the Arctic Ocean.
The second cycle is located in the north-eastern shores of America and includes currents Eastern Hrenland and Labrador. They put in the Atlantic Ocean the bulk of the arctic waters and ice.
The circulation of the northern part of the Pacific Ocean is similar to the north-Atlantic, but differs from it a smaller water exchange with the North Arctic Ocean. Line Kurosio goes in Severoticookeangoing to Northwestern America. Very often this flow system is called Kurosio.
The Northern Arctic Ocean penetrates a relatively small (36 thousand km 3) a mass of ocean water. Cold flows Aleuta, Kamchatsky and Oyasio are formed from cold waters of the Pacific Ocean Outside Communication with Arctic.
Circumpolar Antarctic system Southern Ocean, respectively, the oceanicity of the southern hemisphere is represented by one current Western winds. This is the most powerful flow in the ocean. It covers the Earth with a solid ring in the belt from 35-40 to 50-60 0 Yu.Sh. Its width is about 2,000 km, power 185-215 km3 / s, speed of 25-30 cm / s. To a large extent, this flow determines the independence of the Southern Ocean.
The circumpolar flow of the Western winds is unlocked: branches fill in it Peruvian, Bengelsk, Westavaand from the south, from Antarctica, coastal antarctic trends fall into it - from the seas of Weddell and Ross.
The Arctic system in the circulation of the waters of the World Ocean occupies a special place due to the configuration of the Arctic Ocean. It genetically corresponds to the Arctic Bariac Maximum and the hollow of the Icelandic minimum. The main flow here is West Arctic. It moves water and ice from East to West throughout the Arctic Ocean to the Nansen Strait (between Spitsbergen and Greenland). Then it continues East Holy and Labradorsky. In the East in the Chukotka Sea from the Western Arctic course separated Polarwalking through the pole to Greenland and then - in the strait of Nansen.
The circulation of the waters of the world's ocean dissimmetric relative to the equator. Dyssymmetry of currents has not yet received a proper scientific explanation. The reason for it probably lies in the fact that north of the equator dominates the meridional transfer, and in the southern hemisphere - zonal. It is also explained by the situation and form of continents.
In the inner seas, the circulation of water is always individual.
54. Water sushi. Types of water sushi
Atmospheric precipitates after losing them on the surface of the mainland and islands are divided into four unequal and variable parts: one evaporates and transferred further deep into the continent of the atmospheric drain; The second seeps into the soil and in the soil and for some time it is delayed in the form of soil and underground water flowing into the river and to the sea in the form of ground flow; The third in the streams and rivers flows into the sea and oceans, forming a surface drain; The fourth turns into mountain or mainland glaciers that melt and flow into the ocean. Accordingly, there are four types of water clusters on land: groundwater, rivers, lakes and glaciers.
55. Stock water from sushi. Values \u200b\u200bcharacterizing stock. Factors of Stok.
Stringing the rain and melt water with small jets on the slopes called plane or slopov stock. The jet of the slope flow gather in the streams and the river, forming rUSLOSE, or linear, Called river , stock . Groundwater flows into the river in the form soil or underground Stream.
Full river stock R. it is formed from superficial S. and underground U. : R. = S. + U. . (See Table. 1). Full River Stoke is 38800 km 3, Surface stock - 26900 km 3, Underground stock - 11900 km 3, Ice Stocks (2500-3000 km 3) and the flow of underground waters right in the sea along the coastline 2000-4000 km 3.
Table 1 - Sushi Water Balance without Polar Glaciers
Surface Stock Depends on the weather. He is unstable, temporary, the soil nourishes weakly, often needs regulation (ponds, reservoirs).
Ground Stock. Arises in the soils. In the humidity time of the year, the soil takes an excess of water on the surface and in rivers, and in dry months, groundwater feed rivers. They provide the constancy of the flow of water in rivers and normal water regime.
The total volume and ratio of surface and underground flow varies on zones and regions. In some parts of the continents, there are many rivers and they are full, the river network is large, in others - the river network is rare, small-water rivers or dry at all.
The thickness of the river network and the multi-cycle rivers - the function of the flow or water balance of the territory. The flow is generally determined by the physico-geographical conditions of the area, on which the hydro-geographical method of studying the water sushi is founded.
Values \u200b\u200bcharacterizing stock. Stock from sushi is measured by the following values: layer of flow, flow module, flow factor and flow rate.
Most vividly stock is expressed layer which is measured in mm. For example, on the Kola Peninsula, the layer of the flow is 382 mm.
Module of Stok. - The amount of water in liters flowing down from 1 km 2 per second. For example, in the Neva Pool, the flow module is 9, on the Kola Peninsula - 8, and in the Lower Volga region - 1 l / km 2 x s.
Stream coefficient - shows which proportion (%) of atmospheric precipitation flows into the river (the rest evaporates). For example, on the Kola Peninsula K \u003d 60%, in Kalmykia only 2%. For all sushi, the average long-term flow factor (K) is 35%. In other words, 35% of the annual amount of precipitation flows into the sea and the oceans.
Volume of flowing water measured in cubic kilometers. On the Kola Peninsula per year, there are 92.6 km 3 of water, and 55.2 km 3 runs out.
The drain depends on the climate, the nature of the soil cover, relief, vegetation, weathering, the presence of lakes and other factors.
The dependence of the flow from climate. Climate role in the hydrological mode of sushi is huge: the more precipitation and less evaporation, the more stock, and vice versa. With moisturizing, more than 100% drainage follows the amount of precipitation, regardless of the magnitude of evaporation. With moisturizing, less than 100% drain decreases after evaporation.
However, the role of climate should not be overestimated to the detriment of the influence of other factors. If you recognize the climatic factors decisive, and the rest are insignificant, then we lose the opportunity to regulate stock.
The dependence of flow from soil cover. Soil and soils absorb and accumulate (accumulate) moisture. Soil cover converts atmospheric precipitates into an element of water mode and serves as a river stock in which river. If the infiltration properties and the water permeability of the soils are small, then there are little water in them, it is more spent on evaporation and superficial stock. Well-processed soil in a meter layer can reserve up to 200 mm of precipitation, and then slowly give them plants and rivers.
The dependence of the runoff from the relief. It is necessary to distinguish the value for the drain of the macro, meso and microrelief.
Already with insignificant high elevations, the stock is more than with the plains adjacent to them. So, on the Valdai hill, the flow module 12, and on neighboring plains only 6 m / km 2 / s. An even greater flow in the mountains. On the northern slope of the Caucasus, he reaches 50, and in Western Transcaucasia - 75 l / km 2 / s. If there is no place in the desert plains of Central Asia, then in Pamiro-Ala and Tien Shan, it reaches 25 and 50 l / km 2 / s. In general, the hydrological regime and the water balance of the mountainous countries other than the plains.
The plains show the effect on the stock of meso and microrelief. They redistribute stock and affect its pace. In flat areas, the plains of the stock slower, the soils are saturated with moisture, it is possible to walk. On the slopes, the plane flow turns into a linear one. There are ravines and river valleys. They, in turn, accelerate stock and drain the terrain.
Valley and other decrees in the relief in which water accumulates, supply soil with water. This is especially essential in insufficient moisture zones, where the soils are not missed and the groundwater is formed only when nutrition due to river valleys.
Effect of vegetation on stock. Plants increase evaporation (transpiration) and drain the locality. At the same time, they reduce soil heating and reduce the evaporation from it by 50-70%. Forest bed has a large moisture intensity and increased water permeability. It increases the infiltration of precipitation into the ground and regulates the stock. Vegetation contributes to the accumulation of snow and slows down its melting, so water seeps more in the soil than from the surface. On the other hand, some of the rain is delayed by foliage and evaporate without reaching the soil. The vegetation cover counteracts erosion, slows down the stock and translates it from the surface to the underground. Vegetation supports air humidity and this enhances intramaterial moisture models and increases the amount of precipitation. It affects moisture rotation by changing the soil and its water-receiving properties.
The influence of vegetation is different in different zones. V. V. Dokuchaev (1892) believed that steppe forests are reliable and loyal regulators of the water regime of the steppe zone. In the taiga zone of the forest drain the terrain through more than in the fields, evaporation. In the steppes, forest bands contribute to the accumulation of moisture by snowstand and reduce drain and evaporation from the soil.
Different effect on the stock swam in the zones of excess and insufficient moisture. In the forest zone, they are flow regulators. In the forest-steppe and steppes, their influence is negative, they absorb surface and groundwater and evaporate them into the atmosphere.
Weathered bark and stock. Sand and pebble deposits accumulate water. Often, threads from remote places are filtered, for example, in the deserts from the mountains. On massively crystalline rocks, all surface water flows; On the panels underground water circulate only in cracks.
The value of the lakes to regulate the drain. One of the most powerful flow regulators are large flow lakes. Large lake-river systems, similar to Nevsky or St. Lawrence, have a very regulated stock and are significantly different from all other river systems.
A complex of physical and geographical flow factors. All the factors listed above are cumulatively affecting one on another in a holistic geographic shell system, determine gross moistening of the territory . This is the name of the portion of atmospheric precipitation, which, minus the fast flowing surface flow, seeps into the soil and accumulates in soil cover and in the ground, and then slowly spent. It is obvious that it is the gross moisturizing that has the greatest biological (plant growing) and agricultural (agriculture) value. This is the most essential part of the water balance.
Reasons that violate equilibrium: flows of tides and population change of atmospheric pressure Wind coastline Water drain from sushi
The world ocean is a system of communicating vessels. But their level is not always and not everywhere the same: on one latitude above the Western shores; On one meridian rises from the south to the north
Circulation systems horizontal and vertical wicked mass transfer is carried out in the form of a vortex system. Cyclonic whirlwinds - the mass of water moves counterclockwise and rises. Anticyclonic vortices - the mass of water moves clockwise and lowered. Both movements are generated by front atmospheric perturbations.
Convergence and divergence convergence - the convergence of water masses. The ocean level rises. Pressure and water density increase and it is lowered. Divergence - divergence of water masses. The ocean level decreases. It occurs with the rise of the depth water. http: // www. YouTube. COM / Watch? V \u003d DCE. Myk. G 2 J. Kw.
Vertical stratification The upper sphere (200 -300 m) a) the upper layer (several micrometers) c) layer of wind exposure (10 -40 m.) C) layer of temperature jump (50 -100 m.) D) Seasonal circulation penetration layer and temperature variability The oceanic flows capture only the aquatic masses of the upper sphere.
The deep sphere does not reach the bottom of 1000 m.
The structure of the world's ocean is its structure - vertical stratification of water, horizontal (geographical) explanation, character of aquatic mass and oceanic fronts.
Vertical Stratification of World Ocean
In the vertical section, the thickness of the water decays into large layers, similar to the layers of the atmosphere. They are also called spheres. The following four spheres (layers) are distinguished:
The upper sphere is formed by direct metabolism and a substance with a traposphere in the form of microcirculation systems. It covers a layer of 200-300 m. This upper sphere is characterized by intense stirring, light penetration and significant temperature fluctuations.
The upper sphere falls into the following private layers:
- a) the topmost layer with a thickness of several tens of centimeters;
- b) wind exposure layer 10-40 cm deep; He participates in the excitement, reacts to the weather;
- c) a layer of a leap of temperatures in which it drops sharply from the upper heated to the lower, not affected by the excitement and not a heated layer;
- d) layer of penetration of seasonal circulation and temperature variability.
Ocean flows usually capture the aquatic masses of only the upper sphere.
The intermediate sphere extends to the depths of 1,500 - 2000 m; Its water is formed from surface waters when they are lowering. At the same time, they are cooled and compacted, and then mixed in horizontal directions, mainly with the zonal component. Horizontal transfer of water masses prevail.
The deep sphere does not reach the bottom of about 1,000 m. This sphere is characterized by a certain homogeneity. Its capacity is about 2,000 m and it concentrates more than 50% of the entire water of the world's ocean.
The bottom sphere occupies the lowest layer of ocean strata and extends to a distance of about 1,000 m from the bottom. The water of this sphere is formed in cold belts, in the Arctic and Antarctic and move on huge spaces on deep babins and gutters. They perceive heat from the bowels of the earth and interact with the bottom of the ocean. Therefore, with its movement, they are significantly transformed.
9.10 Water masses and Ocean Ocean Ocean Fronts
The water mass is called a relatively large volume of water, which is formed in a specific water area of \u200b\u200bthe world ocean and possessing for a long time almost constant physical (temperature, light), chemical (gases) and biological (plankton) properties. The aqueous mass moves as a whole. One mass of the other is separated by the ocean front.
The following types of water masses are distinguished:
- 1. Equatorial aquatic masses are limited to equatorial and subequatorial fronts. They are characterized by the highest ocean in the open ocean, low salinity (up to 34-32) salinity, minimal density, large oxygen content and phosphates.
- 2. Tropical and subtropical water masses are created in the areas of tropical atmospheric anticyclones and are limited from moderate belts with tropical northern and tropical southern fronts, and subtropical - the northern moderate and northern southern fronts. They are characterized by increased salinity (up to 37 ‰ or more) and large transparency, poverty with nutritional salts and plankton. In environmental respect, tropical aquatic masses are ocean deserts.
- 3. Moderate aqueous masses are located in moderate latitudes and are limited from the poles of the Arctic and Antarctic fronts. They are distinguished by large variability of properties both in geographic latitudes and by season of the year. For moderate water masses, an intensive exchange of heat and moisture with the atmosphere is characterized.
- 4. The polar aqueous masses of the Arctic and Antarctic are characterized by the lowest temperature, the greatest density, increased oxygen content. Antarctic water is intensively immersed in the bottomhosphere and supply it with oxygen.
Spatial changes in the hydrochemical characteristics of water traced in horizontal and vertical directions are closely related to the circulation and the hydrological structure of the waters of the World Ocean. This connection finds the expression that surface, intermediate and deep water, differing hydrological characteristics, differ also (and sometimes sufficiently sharply) content of biogenic and other elements, oxygen regime, pH, alkalinity and other hydrochemical parameters. The use of hydrochemical data in the analysis of the origin and distribution of various types of water, as is known, is widely used in the practice of oceanographic studies.
Factors that determine the formation of the hydrological structure of the ocean depending on the latitudinal climatic zones, the total circulation of water and the characteristics of the vertical distribution of water, are simultaneously factors, under the action of which the hydrochemical structure of the ocean is created. At the same time, it must be borne in mind that in the formation of a hydrochemical structure, the biological processes belong great importance (for example, the development of phytoplankton). Their effects, especially in surface layers, complicates the dependence of the hydrochemical characteristics from general hydrological conditions.
In the vertical hydrochemical structure of the ocean, as well as during the hydrological unit, usually allocated three zones (or layer): Surface, intermediate and deep. The three-layer vertical hydrochemical structure is due to a significant change in all hydrochemical characteristics vertically and their unidirectional stroke in each of the zones. Generally, these three zones can be described:
1. Surface layer - within its limits there is a photosynthetic zone and the formation of organic matter and the most intensive mineralization processes occurs. It is released by reduced and variable concentrations of biogenic elements, sometimes dissolved with 2, high oxygen content, maximum pH values. The role of the surface layer in the formation of hydrochemical features of water and, therefore, the hydrochemical structure is exceptionally large. Here the basis of the hydrochemical composition is laid, which, when changing the circulation processes, stirring, lifting and lowering water, biochemical processes, causes many typical hydrochemical indicators of water of different origin.
2. Intermediate layerOn the contrary, it is characterized by an increase in the concentrations of biogenic elements and dissolved with 2, a decrease in the oxygen content to a minimum and a decrease in pH. The intermediate layer is important in that it takes place for individual types of water, which leads to the redistribution of the hydrochemical properties of the ocean water, the transfer of biogenic elements, oxygen and other components of the chemical composition. The water of the intermediate layer contributes to the exchange of substance in the ocean.
3. Deep layer - Changes in all hydrochemical characteristics are relatively small, the concentration of dissolved oxygen, the content of biogenic elements varies in different ways - nitrogen and phosphorus is slightly reduced or remains unchanged, and silicon increases, the pH increases.
Vertical hydrochemical structure, keeping its fundamental basis, manifests itself in different ways latitudinal zones each of the oceans. In all areas, changes in the quantitative content and vertical distribution of oxygen and biogenic elements are noted.
1. B. subarctic zone Hydrochemical differences in layers are most weakly pronounced, there is a very high content of dissolved oxygen and minimal biogenic elements. The water of this zone, penetrating south at depths, enrich the intermediate and deep layers of other zones with oxygen.
2. B. northern subtropical zone The distribution of hydrological indicators, including dissolved oxygen and silicon in the layers, is more pronounced.
3. In the waters tropical and Equatorial Zones Further exacerbation of the boundaries between the layers can be traced, the distribution of dissolved oxygen in the surface layer is complicated, the oxygen minimum layer is clearly released. In the intermediate layer, the silicon and phosphorus content significantly increases.
As already noted, the complication of the hydrochemical structure of water is associated with the activation of biological and biochemical processes in the surface layer and the penetration of the aqueous masses with other properties in the intermediate layer.
Regional features of the vertical hydrochemical water structure
AT Atlantic Ocean The following factors affect:
a) The effect of Upwelling (Water Rise) on the distribution of biogenic elements and oxygen in the surface layer in North-West and South-West Africa.
b) the introduction of intermediate subarctic and subnutrctic water, which creates additional layers of a minimum and a maximum of dissolved oxygen at various depths in tropical latitudes.
c) The reduced silicon concentration in the intermediate layer is associated with the penetration of subarmed silicon and Mediterranean waters.
d) the water of the depth layer of the Atlantic Ocean is less rich in biogenic elements than in other oceans, since the intense horizontal and vertical exchange favors aligning their concentrations.
AT Indian Ocean The hydrochemical structure of water is largely different from the structure of the water of the Atlantic Ocean. This is most clearly manifested in equatorial, tropical and subtropical latitudes.
a) Only some quantitative differences in the concentrations of biogenic elements are traced in the south of the Indian Ocean.
b) The surface layer is very clearly expressed in the monsoon area of \u200b\u200bthe Indian Ocean. A sharp increase in phosphorus content is largely determined by high productivity within the upper 50-100 m. The change in the more powerful summer monsoon to decrease the phosphorus content in the photosynthetic zone. Changes in concentrations of dissolved oxygen and biogenic elements are traced almost up to 3000 m (sometimes even more), which determines the lower boundary of the intermediate layer. The feature of the Indian Ocean is also the fact that the water of the intermediate layer is rich in silicon both in the northern and in southern latitudes.
AT Pacific Ocean The main zonal features of the hydrochemical structure are kept in most of its districts.
a) The most significant deviations are observed in the eastern parts of the ocean. They are associated with the penetration of colder waters under the influence of oriental border flows into subtropical and tropical latitudes, with coastal appendication processes, leading to elevated content of biogenic elements, and as a result, the formation of very productive districts. Here in the surface and partially in the intermediate layers, gradients of hydrochemical characteristics increase. In the east of the equatorial zone, the system of subsurface flows rising into relatively small depths and reinforcing the density separation of water creates noticeable differences in oxygen mode of biogenic elements already within the upper 50-meter layer. Penetration into this area of \u200b\u200bwater of various origins, including and rising from depth, leads to a high content of biogenic elements, especially phosphorus, the concentration of which at a depth of 100 m can exceed 2 μg-at / l. With lifting water, a decrease in the power of the surface layer towards the shore to 75-100 m is also connected. It may exceed 150 m in removal from the coast.
b) the subnatrotic zone is limited to the position of the zones of subtropical and equatorial convergence. The lowering of water in the convergence zones creates certain differences in the distribution of density and hydrochemical characteristics in the north and south. In the north, this lowering penetrates to the depths of 400-700 m, in the south - over 1000-1200 m.
c) you can distinguish the differences between the Sanctarctic and Antarctic zones. If in the subnutrctic zone, the intermediate layer of the hydrochemical structure is expressed quite clearly and is characterized, perhaps, even greater variability of the concentrations of dissolved oxygen and biogenic elements than the surface, then in the Antarctic zone, the intermediate layer is extremely small changes in concentrations and is almost no different from the deep.
The latitudinal zonality of the hydrochemical structure of the World Ocean, at the same time, does not exclude significant differences in the distribution of hydrochemical characteristics between the central and peripheral areas of the ocean reflecting circumcontinental zonality . These differences are mostly manifested in the surface layer and affect both the absolute values \u200b\u200bof the hydrochemical characteristics and on their temporary variability.
Daily variability The hydrochemical characteristics on which biological processes affect, covers the surface layer of photosynthesis. In low-productive areas, the burling of oxygen and biogenic elements may vary. The impact of changes in the synoptic scale (the passage of cyclones and anticyclones) is estimated at 20% of the measured hydrochemical characteristics.
Seasonal variability It is traced not only in the entire surface layer, but also in the upper part (and sometimes deeper) intermediate layer. It is most expressed in the zones of intensive convective mixing (water polar and moderate latitudes), in monsoon areas, in the East Equatorial zone of the Pacific Ocean. For the habitat conditions of organisms and the bioproduction process, the role of seasonal changes in hydrochemical characteristics in the surface layer is especially large. The connection of these changes with the latitudinal features of the hydrochemical structure in the ocean is clearly traced. In moderate and high latitudes, seasonal changes in the illumination of biogenic elements, temperature and water dynamics are limited by the development of phytoplankton. The growing season here continues from 1 to 7 months. The basic mass of phytoplankton during this period lives and produces in a relatively thin upper water layer (up to 50-75 m), limited to the bottom of the heap of the density jump, arising from the heating of surface waters. As a result of the vital activity of phytoplankton, the content of biogenic elements is significantly reduced compared to the foresecting period. In certain areas, it becomes as small that it almost completely limits the development of phytoplankton. However, as a result of the autumn-winter cooling of surface waters, the seasonal layer of the jump destroys, convective stirring captures a deeper compared to the warm periods of the year water layers - up to 200-500 m, characterized by a high content of biogenic elements. This determines the leveling of the concentrations of biogenic elements within the 200-260-meter layer and, consequently, an increase in their content in the fotic layer. By the beginning of the next vegetation period, phytoplankton again turns out to be quite well equipped with nutrients. So, in a highly productive area about. Yu. George in the sea of \u200b\u200blivestock The amount of phosphorus and silicon during the growing season in the summer warmer layer (~ 50 m) is an average of 1.4 and 2-3 μg-at / l, respectively. Low silicon content in the first half of the growing season limits the development of phytoplankton. In autumn and in winter, convective mixing captures aqueous thickness of about 200 m, increasing the phosphorus content to 2.2, and silicon to 20 μg-AP / L in the upper layer. In the deep sea part of the Bering Sea, for example, the content of biogenic elements in the fotic layer due to the autumn-winter convective stirring increases from 0.5 to 2.6 μg-at p / l and from 7.14 to 35 μg-at Si / l.
Unlike regards of moderate and high latitudes, in equatorial-tropical regions due to the lack of a clearly pronounced change of seasons, the vertical structure of water within the surface layer retains its main features throughout the year. Dynamic and light conditions here are favorable for the development of phytoplankton all year round, the growing season covers 12 months. There is a constant consumption of biogenic elements, which is not compensated by their regeneration, although quite fast. The same powerful factor in the delivery of biogenic elements, as convective mixing, is missing here. The fotic layer turns out to be depleted nutrients; The neoplasm of the organic matter is sharply weakened. For example, in the western part of the tropical area of \u200b\u200bthe Atlantic Ocean south of the equator, the concentration of nitrogen, phosphorus and silicon remains at a very low level during the entire year - on average 0.5, respectively; 0.2 and 2.6 μg-at / l. And only in the zones of coastal upwelling, partially equatorial divergence, the rise of surface water leads to the formation of areas rich in nutrients and, as a result, highly productive.
The interannual variability of hydrochemical characteristics can reach 10-20 and even 50% of the values \u200b\u200bof hydrochemical characteristics and is associated with the general change in the ocean mode under the action of large-scale ocean oscillations and the atmosphere.
