Good day everyone! You and I know that everywhere on the planet there is a different climate. And what affects the climate, if you need to know this, then read this article...
We talk about climate if we are interested in what the weather will be like in a resort area during a certain period of time, dry or hot.
The sun's rays, in the region of the poles, overcome thicker layers, which means that the atmosphere receives more solar radiation. In the polar regions, the sun's rays, reaching the Earth's surface, are scattered over a much larger area than in the equator region.
The altitude above sea level also affects the temperature. For every 1000 m of rise above sea level, the temperature decreases on average by 7°C.
For this reason, in the high mountain regions of the tropics it is much colder on the sea coasts located at the same latitude, and the cold polar climate reigns on the tops of high mountains.
Mountains also influence rainfall.
Moist oceanic winds that rise over the mountain range contribute to the formation, and heavy precipitation falls on the slopes. Winds tend to pick up moisture and become warmer as they cross the ridge and begin to fall.
Therefore, the mountain slopes facing are saturated with moisture, while the leeward ones often remain dry. The rain shadow is considered to be a dry area.
In coastal areas the climate is usually milder than inland. For example, sea and coastal breezes influence climate. heats up more slowly than the earth's surface.
Warm air rises during the day, and cooler air coming from the sea takes its place. But at night the opposite happens. Breezes blow from land to sea because the sea cools more slowly than the land.
Ocean currents affect temperature.
The warm Gulf Stream crosses diagonally the Atlantic Ocean from the northwestern shores to the Gulf of Mexico.
Sea winds blowing along the Gulf Stream towards the coast in this part of Europe provide a much milder climate than on the North American coast located at the same latitude.
Cold currents also affect the climate. For example, off the southwest coast, the Benguela Current and off the west coast of South America, the Peruvian (or Humboldt) Current cool tropical regions, otherwise it would be even hotter there.
Far from the moderating influence of the sea, in the center of the continents, there is a harsh climate with much colder winters and hotter summers than in the coastal region of the same.
The influence of the sea.
During the warmest time of the year, the average temperature is 15 - 20°C, although away from the coast it is often higher, where the moderating influence of the sea is not felt.
Compared to latitudes located in the same areas, but far from the sea, winter temperatures are unusually high. Here the average monthly temperature is usually above 0°C.
But sometimes, cold continental or polar air causes the temperature to drop, and snowy weather lasts for several weeks.
There is a big difference in precipitation: there is often a lot of moisture in the coastal mountains, but much drier in the flat eastern part.
Previously, deciduous forests (trees shed their leaves in autumn) covered zones of cold temperate climates. But most of them were cut down, and now large areas of these areas are densely populated.
The western part, with cold winters and warm summers, belongs to the cold temperate climate zones. Subarctic climates with very cold winters and short, cold summers are found in other areas, including Siberia and much of Canada.
In these places, the frost-free period lasts no more than 150 days. Most of this subarctic region is occupied by Taiga - giant coniferous forests.
In conditions of a long and harsh winter, coniferous trees (larch, fir, spruce and pine) have learned to survive. All coniferous trees, with the exception of larch, are evergreen, ready to begin to grow as soon as spring warming arrives.
There are no such coniferous forests in the southern hemisphere, because there, at the corresponding latitudes, there are no large areas of land.
Thus, we learned what affects climate, and what climate is in general. Now you can understand why different places on the planet have different climates. Apply knowledge🙂
Covering over 2/3 of the surface of the globe, the World Ocean regulates the metabolism and energy of our entire planet.
In the process of exchanging energy and substances of the World Ocean with the outside world, the basic properties of its waters are formed and changed, and this in turn determines climate change on Earth. Therefore, most climate change projects are based on increasing the flow of heat and moisture from the ocean. Already now, ideas are emerging about artificially changing the cycle of energy and substances in order to create the most favorable conditions for the life and economic activities of all mankind.
Heat exchange between the ocean and the atmosphere- the most important climate-forming factor. The solar energy absorbed by the World Ocean goes, firstly, to maintain a stable thermal regime of waters, which maintains constant temperature fields, secondly, to evaporate a huge mass of water and, thirdly, to turbulent heat exchange with the atmosphere.
Naturally, the World Ocean, which covers most of the globe, absorbs the bulk of solar energy reaching the surface of our planet. Although its amount is approximately the same in the same latitudes, water (due to its high heat capacity) absorbs 25-50% more heat than land. Thus, in the tropical zone of the World Ocean, an average of 100-120 kcal/cm2 or more is absorbed per year, while in the same latitudes on land it is usually only 60-80 kcal/cm2. With distance to the poles, this difference gradually decreases, and in the polar regions, water and land absorb very little solar energy, usually less than 20 kcal/cm 2 per year.
Therefore, almost everywhere the water temperature is higher than the air. Due to the fact that the temperature difference increases from the equator to the poles, the warming role of the World Ocean increases with increasing geographic latitude, reaching its maximum value in the polar regions.
On average, the waters of the World Ocean absorb per year in low latitudes (approximately between 30° N and 30-35° S) from 25 to 75 kcal/cm2. At temperate latitudes, the heat budget varies significantly between the southern and northern hemispheres. In the south, slightly more heat is absorbed than it is expended, while in the north the ocean releases significantly more heat into the atmosphere than it receives from the sun (approximately 50-70 kcal/cm2 per year). This is determined by the difference in the distribution of water and land. In the polar regions, the World Ocean radiates a huge amount of heat into the atmosphere, reaching 50-75 kcal/cm2 per year or more.
In those areas where heat consumption exceeds its supply, the necessary compensation is carried out by transferring heat from low latitudes by currents. Thus, the heat budget of the surface of the World Ocean, on the one hand, has a huge impact on the climate of the entire planet, and on the other, causes water transfer. These movements ultimately spread throughout the entire thickness of the ocean, since even a small transfer in one place (due to one reason or another) causes a whole system of movements associated with the outflow of water and its compensatory entry from the outside. Thus, heat exchange with the outside world gives rise to a complex circulation of water, during which the entire World Ocean is involved in the cycle of energy and substances. Due to this, it accumulates a huge mass of heat, gases, dissolved salts and other substances. Calculations have shown that the column of ocean water contains 500-1000, in some places 1500 times more than the amount of heat that is transferred through its surface during the year. Therefore, all interannual changes in climate processes are easily covered by the internal reserves of the World Ocean.
Water exchange between the ocean and the atmosphere- another important process affecting the Earth's climate. Its main features are determined by the difference between evaporation and precipitation. The total mass of water evaporating from the surface of the World Ocean is about 355 thousand km 3 per year, and almost 320 thousand km 3 falls back per year. The rest (which is approximately 1/10 of all evaporated moisture) is carried away in the form of water vapor to land. Having fallen here, this water is again carried by rivers into the seas and oceans, thus closing the general water cycle on the planet.
The bulk of water evaporates in the tropical and subtropical latitudes of the World Ocean, where the influx of solar heat is greatest, and the predominance of anticyclonic weather causes minimal precipitation. In the low latitudes of the World Ocean, only in the equatorial zone does precipitation prevail over evaporation, due to rising currents in the atmosphere. In temperate and high latitudes, starting from about 40°, precipitation exceeds evaporation.
The total amount of water in the atmosphere in the form of water vapor is estimated at only 13 thousand km 3. With changes in the thermal regime of the planet, the amount of water vapor in the atmosphere should change significantly. Such fluctuations are especially large during periods of long-term warming and cooling of the climate. In our time, the average temperature of the Earth's air shell is 14°, whereas before the last (Quaternary) glaciation it was 22°. Therefore, much more water evaporated from the surface of the World Ocean. Accordingly, the remaining components of the planet’s water balance had to change. During the era of Quaternary glaciation, the average temperature of the atmosphere, according to available estimates, could vary from 2° (during the period of maximum glaciation) to 17° during interglacial periods of warming. Based on the sediments of the bottom of the equatorial region of the Atlantic Ocean, it was revealed that the water temperature on its surface during the Ice Age dropped to 17°, while in our time it is 26°. According to some data, during the period of greatest glaciation of the Earth, the maximum volume of ice could be five times greater than now, reaching approximately 150 million km 3. There are calculations showing that for the occurrence of an ice age, a decrease in the average temperature of the atmosphere by only 4° is sufficient. At the same time, a huge amount of water vapor in circulation is concentrated on the land surface in the form of ice sheets.
The study of the water cycle and the role played by the World Ocean is of great importance not only for understanding the influence of moisture circulation on the formation and changes in the nature of the globe, but also for elucidating the impact of water vapor on the thermal regime of the entire planet. Some scientists believe that with increasing evaporation of water from the surface of the World Ocean, air temperature should increase, which affects climate warming. This occurs due to the so-called “greenhouse effect” of water vapor; By transmitting short-wave solar radiation, they block long-wave thermal radiation from the Earth.
Some features of gas exchange between the ocean and the atmosphere. It is possible that this process also has a significant impact on the climate of our planet, due to changes in carbon dioxide in the atmosphere, which is also characterized by the “greenhouse effect”. The carbon dioxide theory of climate fluctuations is based on this phenomenon.
Currently, the air envelope of the Earth contains approximately 2300 billion g of carbon dioxide, which is only 0.03% of its total mass. In the past, this percentage may have varied significantly. It would be enough for it to decrease by half compared to the present time (up to 0.15%) for the average temperature of the entire planet to drop by almost 4°, which is enough for the emergence of an ice age. Similar conditions, in particular, could have occurred during the Carboniferous period, when a very large amount of carbon dioxide was removed from the exchange between the atmosphere and the hydrosphere.
Over the last century, the content of carbon dioxide in the Earth's air has increased by 13%. Due to this, the average temperature of the atmosphere could increase. There are forecasts according to which only due to the combustion of fossil fuels and the reduction of forests by the end of this century, as a result of a further increase in the amount of carbon dioxide, the average air temperature may increase by 2°.
These works apparently do not take into account the role of the World Ocean in the gas cycle. Due to its colossal area and high dissolving capacity of sea water, the World Ocean is capable of absorbing and releasing huge amounts of gases, maintaining a fluid equilibrium between the gas composition of the atmosphere and the hydrosphere. In particular, the World Ocean should absorb about half of the carbon dioxide that will be added to the air envelope of the globe. After about a thousand years, carbon dioxide dissolved in seawater may come into equilibrium with the pressure of carbon dioxide in the atmosphere. The circulation of this gas is also associated with the most complex biochemical processes through which it is converted into carbon dioxide salts. As is known, they form the basis of the skeleton of most animals; carbonate sediments of the bottom and rocks are composed of them; in fresh waters, the main mass of dissolved salts is made up of carbonate compounds.
Speaking about the gas exchange of the World Ocean with the atmosphere, it should be borne in mind that it contains twice as much oxygen as in the air; the volumetric ratio of oxygen to nitrogen in ocean waters is 1:2, and not 1:4, as in the atmosphere. Moreover, everywhere, from the surface to the greatest depths, the oxygen content in the waters of the World Ocean is so high that it not only ensures the active development of oxidative processes, but also the presence of a significant amount even at the very bottom. The exception is some seas that have very limited water exchange with the ocean and large continental runoff. As a result of strong desalination of the surface layer, a sharp stratification of water is created, severely limiting vertical mixing, due to which not only reduction processes predominate in the depths, but also hydrogen sulfide appears. Similar conditions are observed in the Baltic and Black Seas and in the Caspian Sea, which has completely lost contact with the ocean.
If oxygen on our planet was formed mainly due to photosynthesis, then in this case the World Ocean should have played a significant role.
The main features of the interaction between the circulation of the atmosphere and the waters of the World Ocean. All the most important features of the cycle of energy and matter are realized in the process of circulation of water and air masses. They are determined by the uneven distribution of solar energy around the globe and changes in its receipt over time. In accordance with the location of water and land, instead of continuous latitudinal zones of high and low pressure, quasi-stationary cyclones and anticyclones are formed in the atmosphere. While the centers of atmospheric action within continental spaces, as a rule, undergo seasonal changes, moving from anticyclones in winter to summer cyclones, over the World Ocean the same pressure centers usually remain throughout the year. Thanks to this, cooled air is carried from the continent to the ocean in winter, and from the ocean to land in summer, which helps to soften the Earth's climate.
We will not present here maps of air pressure and prevailing winds, as well as surface currents, which are quite well known from numerous atlases and even school textbooks. When examining a map of the World Ocean, it is easy to notice that the oceans narrow to the north, reach their greatest width at low latitudes, and in the southern hemisphere, between the forties and Antarctica, there is a continuous expanse of water.
As in the atmosphere, there are two types of water circulation in the hydrosphere: cyclonic and anticyclonic. In the northern hemisphere, as is known, in anticyclonic gyres, water and air masses move clockwise, and in cyclonic gyres, counterclockwise; in the southern hemisphere the direction of movement is reversed. These cycles are quasi-stationary, that is, they constantly exist in the same areas of the globe. Both types of circulation of air and water masses are closely interconnected, so that the same flows are peripheral parts of adjacent circulations, successively replacing each other with geographic latitude. Therefore, the same masses of water and air successively pass from one cycle to another, thus ensuring continuity of movement. The intensity of water transfer is directly dependent on the stability of air flows. As wind transport increases from the poles to the equator, the stability and speed of the main currents that form the water cycles increase in the same direction. An increase in the intensity of atmospheric circulation in winter and a weakening in summer leads to the fact that the intensity of water circulation slightly increases in the cold season and decreases in the warm season. However, the entire system of water and air circulation over the oceans remains unchanged, only shifting slightly to the south in the northern hemisphere and to the north when the cold period sets in in the southern half of the globe. The exception is certain areas, mainly associated with monsoon wind changes; this primarily applies to the northern Indian Ocean, the Sunda Archipelago, the area located west of Australia, and some other areas of the World Ocean.
In accordance with the presence of quasi-stationary cyclones in the atmosphere at high latitudes, a cyclonic circulation of water is created, and in low latitudes, where anticyclones form, an anticyclonic circulation of water is observed. In the northern parts of the oceans, due to the high activity of baric lows, cyclonic water circulations are very pronounced and very intense. In the southern parts of the oceans, under conditions of continuous water space, the cyclonic circulation of waters is much weaker. They are formed as a general circulation between the coastal Antarctic Current, going to the west, and a powerful flow, which is located to the north and carries the flow of water to the east. Intense cyclonic circulation of water is created only in certain places, where the configuration of the coast of Antarctica is favorable for this. These phenomena take place in the Weddell, Ross, and Bellingshausen seas, in the southwestern and southeastern parts of the Indian Ocean.
Anticyclonic water circulations, located in the tropical and subtropical latitudes of the World Ocean, extend over a vast area, approximately from the equatorial region to the forties latitudes in both hemispheres. In accordance with the great stability and strength of the prevailing winds here, the currents that make up the anticyclonic gyres have the greatest constancy and power in relation to other flows.
Until recently, it was believed that anticyclonic gyres spread across the entire width of the oceans. However, it turned out that in the eastern parts of the oceans anticyclonic water circulations are replaced by cyclonic ones. These ideas arose as a result of calculations of water circulation carried out at the Institute of Oceanology of the USSR Academy of Sciences, based on indirect data (temperature and salinity of water).
How can we explain the fact that under the influence of the same pressure field - a subtropical anticyclone - two different water circulation systems are simultaneously formed: anticyclonic and cyclonic? Here the theory of the Soviet oceanologist V.B. Shtokman comes to our aid, according to which, with an uneven transverse speed of a wind flow in one direction (in this case, a very stable trade wind), currents in mutually opposite directions can arise. Indeed, an analysis of wind vorticity maps showed that in the area of subtropical pressure maxima, anticyclonic water circulations should be created only in the western parts of the oceans, while cyclonic ones should be created in the eastern parts. Thus, it turns out that in the tropical regions of the oceans along their eastern coasts, water is transferred from the equator to temperate latitudes. Previously, there was an idea that the Canary, Benguela, California and Peruvian currents carry their waters here in the opposite direction. According to new maps of water circulation, it turns out that these currents move from the continents into the open ocean at about twenty degrees of latitude. Apparently, some of their branches may remain along the banks. It must be assumed that in these areas there is a complex system of currents, aggravated by the effect of trade wind upwelling (the phenomenon of rising deep waters that occurs off the tropical coasts of the eastern parts of the oceans as a result of the movement of surface waters by trade winds). Subsequent expeditionary studies will have to provide the necessary additional information to clarify the conditions that are formed in the low latitudes of the eastern parts of the oceans.
As a result of the circulation of “water and air masses within cyclonic and anticyclonic circulations, a whole system of vertical movements arises. With cyclonic circulation of water, they rise in the central part of such a circulation and fall along the periphery, and with anticyclonic circulation, the opposite occurs. In the atmosphere, due to the reverse change in density with distance from the surface of the globe (decreasing in the atmosphere and increasing in the hydrosphere), upward movements are observed in the center of cyclones, and downward movements are observed in anticyclones. Thus, significant masses of water and air are involved in the cycle of energy and substances that occurs near the surface of the planet. In the atmosphere, vertical movements caused by surface forms of horizontal circulation extend mainly to the troposphere; in the process of its interaction with the stratosphere, even more complex types of transformation of energy and substances are created. In the World Ocean, which is limited by the bottom and has a relatively small vertical extent, the movement of water ultimately spreads throughout the entire thickness. Due to this, a huge amount of energy and substances is accumulated. The features of their accumulation and transport in different parts of the World Ocean are determined by the structure and vertical circulation of water.
Structure of the World Ocean waters. In contrast to the atmosphere, the structure of which is more or less detailed, the structure of the waters of the World Ocean is still very poorly studied.
The great similarity of the atmosphere with the structure of the waters of the World Ocean, the uniformity of the development of processes and, in connection with this, the conditions created in their upper and lower parts, led to the idea of dividing ocean waters into the troposphere and stratosphere. Indeed, the troposphere of the World Ocean, like the troposphere of the air envelope, is characterized by intensive development of processes associated with the influence of the entire set of factors influencing the surface of the globe; its thickness is also determined by the degree of development of convective processes. The stratosphere of the World Ocean is represented by various layers of water, significantly different in their properties and the processes occurring in them. In contrast to the troposphere, where vertical mixing predominates, in the ocean stratosphere the main role is played by the transport of water in the horizontal direction. Between the troposphere and the stratosphere of the ocean there is also a small transition layer - the subtroposphere. This analogy was first noticed back in the 30s of our century.
In oceanology, the idea has long been established that there are several types of water masses in the World Ocean, the names of which are given in accordance with the depth of their location: surface, intermediate, deep and bottom. Each such type, in turn, is divided into a number of water masses that differ in their properties, conditions of formation, location and nature of movement from other waters located within the same depths. For example, surface water masses, in accordance with zonal changes in natural conditions, are divided into polar, subpolar, temperate, subtropical, tropical and equatorial. In turn, seas are divided into subtypes in connection with the specific conditions that develop in a given latitudinal zone in a particular ocean, such as the north tropical, Pacific, south tropical Pacific, equatorial Atlantic, Indian and Pacific, etc. Similar the division also exists in relation to intermediate, deep and bottom water masses.
Thus, water masses mean large volumes of water, distinguished by specific characteristics that they acquire in certain areas and retain when moving outside the area of their formation. These characteristics persist even after significant transformation that occurs as a result of mixing with other types of water.
Since each type of water mass is characterized by similar processes that change in accordance with the depth of their location, for understanding the structure of the waters of the World Ocean, changes in the properties of water vertically are of primary importance. In the horizontal direction, it is not the structure of water that changes, but the characteristics of similar water masses. Therefore, the structure of water should be understood as the patterns of changes in the physical and chemical properties of water vertically, manifested in a certain combination of different water masses in depth. The layer of water within which the same type of water masses are located was called the structural zone. In this case, only the surface structural zone belongs to the troposphere of the ocean, and the intermediate, deep and near-bottom zone belongs to the stratosphere.
Now let's briefly look at the characteristics of each structural zone.
The surface structural zone or troposphere of the ocean is characterized by the most intensive development of processes, due to the active exchange of substances and energy with the atmosphere and the fact that it is exposed to all external forces (solar radiation, wind and the rest of the external physical and geographical factors). The stratification of its waters is determined mainly by the interaction of the processes of wind and convective mixing, as well as the circulation of water caused by all the mentioned factors. Wind mixing leads to the creation of a relatively homogeneous surface layer, the lower boundary of which is determined by the depth of propagation of wave mixing. This homogeneity is constantly disrupted by processes of interaction with the atmosphere, causing heating or cooling, desalination or salinization of surface waters, which leads to an increase or decrease in their density. At the same time, these processes excite convection, thermal in the cold season and salt-bearing in the warm season. Cooled or salted waters in places of intense development of convection, penetrating into the surface layer, then spread in the horizontal direction, being involved in the complex system of water circulation in the surface zone of the World Ocean; Due to this, in high latitudes in the warm season, a cold layer remains under the heated surface layer, and in low latitudes, subsurface salty waters remain. They determine the characteristics of the lower layer of the surface zone. Thus, within the surface structural zone, a surface and a lower (or convective) layer are distinguished, separated by a shock layer. The average thickness of the surface layer throughout the World Ocean is 20-30 m, the shock layer is approximately 2 times larger, and the convective layer is 150-200 m.
The average depth of the lower boundary of the surface structural zone in the World Ocean is noted to be 200-250 m. Moreover, it turns out to be elevated in high latitudes and in the equatorial region as a result of the predominance of ascending currents and subsidence in temperate latitudes due to more intense convection. The difference in its position in each of the oceans is small.
The transition zone, or ocean subtroposphere, appears to be more associated with intense vertical mixing processes characteristic of the troposphere than with less active processes characteristic of the ocean stratosphere, in particular, its intermediate zone. This may lead to considerations about whether it is necessary to distinguish a transition zone at all and whether it should be attributed to the ocean troposphere. Subsequent studies will have to provide the necessary clarity on this issue. At this stage, its identification seems necessary, since the presence of such a transition zone between the troposphere and the stratosphere of the ocean, which differ significantly in the nature of the processes occurring in them, is quite natural. The lower boundary of the subtroposphere on average throughout the World Ocean is located at depths from 300-350 to 500-550 m. The average thickness of the subtroposphere in the World Ocean from 200-250 m in high latitudes increases to 250-300 m in temperate latitudes and decreases in low latitudes up to 150 m.
The intermediate zone differs sharply from the waters above and below in its temperature (in high latitudes) or salinity (in temperate and tropical regions). The intermediate water masses located here, formed mainly from surface waters, are widespread throughout the World Ocean. The lower boundary of the intermediate zone is located at depths from 1000 to 2000 m. In this case, the sea drops near Antarctica to 1500-1700 m due to the predominance of downward flows, then rises quite sharply in the subantarctic region to 800-1100 m due to the presence of cyclonic water circulation here, on the contrary , drops greatly in areas of subtropical anticyclonic water circulation to 1800-2000 m and rises significantly between them to a depth of 1100-1200 m in the equatorial region. The thickness of the intermediate structural zone in the World Ocean varies on average from 600-800 to 1200-1400 m. Moreover, in high latitudes and in places of anticyclonic water circulation, where subsidence of water masses predominates, it is thicker, amounting to 1200-1500 m; in the equatorial zone it is thinner, decreasing to 900-1000 m, and in areas of cyclonic water circulation - even to 600-800 m due to the prevailing rise of waters. Thus, the intermediate zone is 4-6 times thicker than the surface and transition structural zones.
The deep structural zone is characterized by the greatest vertical development compared to all other structural zones. Its lower boundary is perhaps easier to determine than all other boundaries of the structural zones. The reason is that the processes occurring on both sides of this boundary are different. Above it, in the deep structural zone, processes associated with the general patterns of water circulation predominate; below, in the near-bottom structural zone, the properties of water are mainly formed due to local conditions, which primarily include: bottom topography and in accordance with These include the features of water exchange, the interaction between the aquatic environment and the ocean floor, as well as adiabatic processes. Therefore, the position of the lower boundary of the deep structural zone is to a much lesser extent related to those factors that determined the configuration of the corresponding boundaries of the overlying structural zones.
The lower boundary of the deep structural zone, on average throughout the World Ocean, can be traced at a depth of about 4000 m. It is highest near Antarctica, rising to 2500-3500 m, which should be associated with the bottom Antarctic waters; forming here and then descending along the continental slope of the southern continent, they then spread far within the bottom structural zone. With distance from Antarctica, the lower boundary of the abyssal structural zone drops sharply in the region of the subpolar basins bordering this continent. In the rest of the World Ocean, it is difficult to discern any general, well-defined patterns in the position of this boundary. The thickness of the deep structural zone under conditions of its relatively little changing lower boundary is determined by the patterns of changes in the upper boundary, which are clearly linked to the characteristics of water circulation. In accordance with this, the thickness of the deep zone in the equatorial region turns out to be very large - about 3000 m. It is approximately the same in the area of the subantarctic basins. The smallest thickness of the deep structural zone is observed in areas of tropical anticyclonic water circulations, where it is reduced on average across the World Ocean to 1200-1700 m. Another similar region is the Antarctic region, where the upper boundary of the zone under consideration falls and the lower one rises. In other parts of the World Ocean, the thickness of the deep structural zone is 2000-2500 m. Thus, it is characterized by the greatest thickness, approximately 2 times greater than the thickness of the intermediate structural zone.
The bottom structural zone is characterized by large changes in thickness associated with changes in bottom depth. Therefore, it is advisable to define it in relation to some conditional depth. The most convenient reference surface is a surface of 5 thousand m. Thus, the conditional thickness of the bottom zone will be determined between its upper boundary and a depth of 5000 m. Within these boundaries, its thickness is mostly 1000-1500 m. The bottom structural zone has the greatest thickness in The Pacific Ocean due to the slightly higher position of its upper boundary and especially significant bottom depths. It is thinnest in the Atlantic Ocean, where shallow bottom depths predominate and its upper boundary is located deeper.
In conclusion, it is necessary to point out that the structure of the waters of the World Ocean is extremely stable. A comparison of data collected over the entire history of oceanology has shown the invariance of conditions throughout the entire thickness of the oceans. This can be explained by the quasi-stationary nature of vertical water circulation and the fact that each structural zone has an independent water circulation system. All the variability of natural conditions, observed from season to season and from year to year, arising in the process of interaction between the atmosphere and the hydrosphere, is mainly limited to the troposphere of both shells. In the stratosphere of the World Ocean (with its enormous size, colossal amount of energy and substances, stability of structure and water circulation), all these changes are completely leveled out. This maintains the general uniformity of natural conditions characteristic of each individual planetary cycle of development of our planet. With the transition to another planetary cycle, the nature of the interaction between the atmosphere and the hydrosphere will change, in accordance with which the circulation of water and air masses, the structure of water, and, consequently, the general circulation of energy and substances will change. In this light, the consideration of vertical water circulation is of particular interest.
Basic concepts of vertical circulation and water transport in the meridional plane of the oceans. By considering the vertical circulation of water in the meridional extent of the oceans, we can identify the main patterns inherent in the transport of water in each ocean and compare them with each other. At the same time, the meridional circulation of water plays a very important role in the circulation of energy and substances. Within the surface and intermediate structural zones, meridional water transfers occur not only along the periphery of cyclonic and anticyclonic water circulations; The rise of water in the central parts of cyclonic systems and their descent in anticyclonic systems leads to the emergence of meridional water exchange between them. In the deep and near-bottom structural zones, meridional water transfers, apparently, are generally predominant.
Ideas about the vertical circulation of water in the meridional plane of the oceans are based on calculations made using indirect data (water temperature and salinity). The diagrams constructed from them were then generalized in order to get an idea of the main water transfers. The thickness of the arrows reflects, in accepted gradations, the prevailing rates of water transfer in the horizontal direction, and the heads of these arrows reflect the magnitude of vertical movement.
Without going into a detailed analysis of the scheme of the main water transfers, which is of special interest, we will briefly dwell only on the general patterns. The most important of them, as already mentioned, should be considered the presence of independent water circulation systems in each structural zone. At the same time, active water exchange occurs between the structural zones, which is also characterized by great constancy, due to which the amount of water passing from one structural zone to another remains unchanged. In addition, it is necessary to note the uniformity of water transport in the meridional planes of the oceans and the good connection between vertical and horizontal water circulation. In low latitudes, in accordance with the presence of horizontal quasi-stationary anticyclonic water circulations in their central parts (approximately between 10 and 30° of the northern and southern hemispheres), the subsidence of water predominates; in high latitudes, the rise is due to the existence of horizontal cyclonic circulations. At the same time, upward movements cover a much larger thickness of water, often from the very bottom to the surface of the ocean, while downward movements extend to a relatively shallow depth (no more than 1500-2000 m). This is understandable, since it is much more difficult to pump less dense water from the upper layers of the ocean into the depths with high pressure and increasing density than to lift it into layers with lower density and pressure.
Within the surface and intermediate zones, there is a certain predominance of meridional water transport in the direction from high latitudes to the equator. In the deep and near-bottom zones, the meridional transport of water is often traced along almost the entire length of the oceans. In the Antarctic region, quite naturally, completely identical patterns of vertical water circulation were obtained.
The values of the vertical components of current velocity on average throughout the World Ocean from the highest values of the order of several units per 10 -3 cm/sec in the surface structural zone decrease to several units per 10 -4 cm/sec in the deep and bottom zones without significant changes in the latitudinal zone direction. Changes in the horizontal components of currents are more noticeable, as are the differences in the absolute values of velocities between individual structural zones. They are maximum in the equatorial region of the surface zone, reaching an average of 35 m/sec throughout the World Ocean. With increasing latitude, the speed of meridional water transport gradually decreases to 1-2 cm/sec at 40-50°, and then increases again to 10-20 cm/sec in the subpolar regions. In the intermediate zone, the speed of meridional water transport is already significantly lower; they vary from a few tenths to 5-8 cm/sec. In the deep and near-bottom zones, values from 0.2 to 0.8 cm/sec predominate, and in the first of them, in general, they are somewhat higher.
Our understanding of the vertical circulation of water and the associated circulation of energy and substances is still very limited. Their in-depth study will allow us not only to understand the laws that determine the formation and change of nature on our planet, but also to find ways to control them.
The ocean and the problem of climate change. During the circulation of air masses under the ocean, their basic properties are formed, which have a great influence on the climate. As an example, we can point out that the mild climate of Europe is associated with the removal of a huge mass of heat and moisture from the Atlantic by the prevailing westerly winds; According to existing calculations, through every centimeter of the western coast of this continent, 4 thousand billion calories of heat are brought from the ocean throughout the year. The powerful warm Gulf Stream plays a major role in heating the North Atlantic, bringing well-warmed tropical waters to the shores of Europe. Thanks to its polar branch, which goes around Scandinavia, the Murmansk port is accessible to ships throughout the year, while the Zhdanov port on the Sea of Azov, located 2,500 km to the south, freezes for about two months.
North America is deprived of such beneficial influence of the ocean due to the fact that it is fenced off by the high Cordilleras. Warm and humid air brought by westerly winds, accumulating near the mountain range; rises upward, giving off heat to the upper layers of the atmosphere, and water vapor, condensing, pours out as rain, then rolling down the slopes back into the ocean. This is one of the main reasons causing the desalination of surface waters of the Pacific Ocean, which leaves a large imprint on the stratification and vertical circulation of its waters.
Another similar example of the close interaction between the hydrosphere and the atmosphere is the region of pronounced monsoons, the scope of which includes the south-eastern part of Asia, the northern Indian Ocean and the Sunda archipelago. Due to the seasonal change in the direction of the monsoons, the nature of water circulation in the northern part of the Indian Ocean completely changes. The equatorial zone with its specific climatic and hydrological conditions is shifting to the Southern Hemisphere, and there is a sharp desalination of the surface waters of the Bay of Bengal and adjacent waters with all the ensuing consequences in relation to the structure and vertical circulation of water. Only during the winter monsoon, blowing from the mainland, the direction of which coincides with the trade winds characteristic of these latitudes in all other parts of the World Ocean, does a normal water circulation system form in the north of the Indian Ocean. The summer monsoon, which has the opposite direction, leads to a complete change in water transport. Warm air rich in water vapor brought from the ocean creates a very stuffy and humid climate on land. When meeting the Himalayas, air masses begin to rise, and a huge amount of water, flowing down the slopes, is carried back into the ocean by rivers.
On the contrary, the sharply continental climate of Asia and North America is due to the very weak influence of the ocean. This is where the ideas of artificial climate change arose by increasing the impact of powerful currents passing nearby: the Gulf Stream and Kuroshio. In the United States, at the end of the last century, a climate mitigation project emerged by blocking the Strait of Florida and building a canal across the Florida peninsula (at its junction with the mainland) so that the Gulf Stream would pass along North America over a much longer distance than it does now. Thus, it was intended to create a subtropical climate in the eastern part of the United States. However, this project had to be abandoned, since it was proven that in conditions of the predominance of westerly winds it is difficult to expect much effect from it. Subsequently, for the same purposes, it was proposed to divert the antipode of the Gulf Stream, the cold Labrador Current, into the ocean using a dam. This project continues to be discussed now, and the opinions of experts are divided: some believe that it can play a big role in improving the climate, while others are trying to prove the opposite.
A similar project exists regarding the impact on Kuroshio, in order to soften the climate of our Far East, Sakhalin and Kamchatka. Soviet engineer N.G. Romanov, by constructing a dam in the Nevelskoy Strait (separating Sakhalin from the mainland), hopes to increase the influx of warm water into the Sea of Okhotsk. With the help of gates that open only to the north, he proposes to pump water from the Sea of Japan, driven by tidal water. Thanks to this, according to the calculations of the author of the project, the average annual water temperature on the surface of the Sea of Okhotsk will increase by 10° and heat transfer to the atmosphere will be so great that the climate of the adjacent land areas will become much milder.
Another Soviet engineer P. M. Borisov is successfully working on a project to change the climate of the Arctic by destroying the ice of the Arctic Ocean in order to sharply increase heat transfer into the atmosphere. For this purpose, it is planned to block off the Bering Strait with a dam with powerful pumps to pump cold Arctic waters into the Pacific Ocean. Thus, P.M. Borisov expects to significantly increase the compensatory influx of warm waters from the Atlantic Ocean, which should lead to the melting of ice and a significant increase in water temperature.
Despite the attractiveness of the idea of transforming the nature of the harsh Arctic, not everything is clear about its implementation. And this primarily relates to the possibility of destroying ice. The fact is that during years of increased cyclonicity in the Arctic, the transfer of heat and moisture from the Atlantic to Europe and vice versa decreases. With the destruction of ice, heat transfer into the atmosphere from the ocean surface will greatly increase. This will lead to a sharp increase in cyclonicity in high latitudes and a strong weakening in the temperate zone. The latter will cause a significant decrease in precipitation: the continental climate will increase in most of the Soviet Union due to a decrease in air temperatures. Thus, changes in climatic and natural conditions in temperate latitudes can have a detrimental effect on human economic activity. One should also be wary of the movement of the desert zone to the north. This example shows how carefully one must approach the development and evaluation of all kinds of projects, in the context of the complex system of interaction that takes place between the ocean and the atmosphere. Disruption of one of the chains of the general circulation of energy and substances can entail consequences that are not always desirable.
In our space age, very bold ideas and projects have begun to appear that should allow man to radically remake the nature of the entire planet based on the use of huge additional masses of solar energy. One such project was proposed by the young Soviet engineer V. Cherenkov, another by the famous American physicist Dyson. Without considering them in detail, we will only note that projects for a radical restructuring of the Earth’s nature, based on additional solar energy, have great advantages over local climate change projects in individual parts of the Earth. The latter, as we saw in the example of the transformation of the nature of the Arctic, while improving conditions in one part of the planet, can lead to their deterioration in another place. A general increase in the influx of solar energy on the entire planet, without disturbing individual links in the cycle of energy and substances, will lead to an artificial transition to a new cycle of development of natural processes. Over time, man will find ways not only to change the general cycle of energy and substances on Earth, but, apparently, will learn to regulate it in order to create such natural conditions that will be most favorable for him.
North America, together with its islands, is located between 83 and 7 ° N. w. , i.e., it crosses from north to south all the climatic zones of the northern hemisphere, with the exception of the equatorial one. At the same time, the widest and most massive part of the continent is included within the subarctic and temperate zones, and a somewhat smaller part is within the subtropical zone. The narrowest part of North America is located in the tropical and subequatorial zones; The Arctic zone includes mainly islands. These geographic features create large differences in heating between the northern and southern parts of the continent. Annual amounts of solar radiation vary from 7560 MJ/m2 (180 kcal/cm2) in the southwest to 3360 MJ/m2 (80 kcal/cm2) in northern Canada. At the same time, the winter radiation balance of the continent’s surface is positive only south of 40° N. w. , but in most of North America it is negative. In almost all of Greenland, the radiation balance is negative throughout the year.
The relief of North America, with its characteristic submeridional extension of the main elements, favors the penetration of air flows from the east, from the Atlantic, where there are no significant orographic barriers, and makes it difficult for air masses to spread inland from the Pacific Ocean. The existence of a strip of plains between the Arctic Ocean and the Gulf of Mexico in the middle part of the continent and the absence of latitudinal orographic boundaries create conditions for meridional air exchange between Arctic and tropical latitudes in all seasons of the year.
In the Atlantic Ocean, contrasts in heating between north and south are enhanced by the Gulf Stream and the cold Labrador Current, which occur in the Newfoundland area. At the point where warm and cold waters converge, conditions are created for the formation of cyclones and cyclonic activity. In the Pacific Ocean, a warm current running north from the 40th parallel creates a positive winter temperature anomaly, although not as significant as off the coast of Europe. Under the influence of the cold California Current running south from the 40th parallel, the ocean is between 20 and 40° N. w. loses up to 2520 MJ (60 kcal/cm2) per year per 1 m2 of surface, i.e., approximately half of the heat it receives from total radiation.
The general atmospheric circulation over North America is approximately the same as over Eurasia, but differences in the size and orographic structure of the two continents cause differences in both local circulation conditions and in the distribution of temperatures and precipitation.
The main type of atmospheric circulation over most of North America is west-east transport, however, due to the peculiarities of the continent's orography, the influence of oceanic air is manifested mainly on the Pacific coast and on the western slopes of the Cordillera. Pacific air penetrates into the interior of the continent through low areas of mountains and transverse valleys, experiencing intense transformation and losing a significant part of its properties immediately east of the Cordillera. The interior of North America is the arena for the formation of continental air. However, the significantly smaller size of the land compared to Eurasia does not create conditions for the formation of such a powerful winter maximum as the Asian one. Therefore, the Atlantic part of the temperate zone of North America is characterized by cyclonic activity throughout the year.
The most important feature of the seas and oceans is the close connection of thermal phenomena in water and air.
Residents of villages and towns located far from the sea coast often forget about the sea, forget about what they owe to the sea. Meanwhile, the role of seas and oceans in the life of every person is enormous.
The powerful influence of the oceans is felt not only on its shores, but also in the interior of the continent, thousands of kilometers from the coast.
The Earth's climate depends on many factors, but the main ones are the action of the sun and oceans. Because the land and oceans are unevenly distributed, powerful transfers of air masses occur across the globe and steady winds blow. Water is a very good store of solar heat. Land - although not all the same - retains heat much worse. It quickly loses a significant part of the beneficial solar heat through reflection and back radiation and this differs from the sea.
The sea, on the contrary, takes almost all the heat and hides it in the depths. That portion of solar heat that is retained by land is stored only in the upper layer. Everyone can feel this warmth on a fine sunny day - just touch the glowing, almost heated sand. But once the sun sets, the land quickly cools down. That’s when the warmth hidden by the sea becomes noticeable. At night, the water turns out to be warmer than the air. Depending on where it is colder, the wind blows either from land to sea (at night) or from sea to land (during the day). The water is agitated and mixed. Particles heated by the sun are replaced by cold ones, which in turn heat up and give way to others. As a result, heat spreads to a depth of several tens of meters. It cannot quickly disappear from such a depth when it gets cold, because water has low thermal conductivity. The specific heat of water is about twice that of land and almost four times that of air. Taking into account, in addition, the low density of air (almost seven hundred and seventy times less than the density of water), we find that each cubic centimeter of water, having cooled by 1°, will heat more than 3,100 cubic centimeters of air by the same amount. This is why the sea slowly and evenly warms the land during cold periods.
True, in summer the breath of the sea seems harsh and cold. Heavy clouds filled with moisture slowly rise from the horizon. They approach the shore, cover the bright cheerful sky and go hundreds and thousands of kilometers to land. Rains, often accompanied by lightning and thunder, fall not only over coastal areas, but also over parched steppes and deserts. And every green leaf that grows luxuriantly after a blessed shower, in essence, testifies to the great role of the seas and oceans in the development of life on Earth. In winter in Western Siberia there are bitter frosts and smoke hangs in lazy, gray pillars above the chimneys of houses, and hasty passers-by run through the streets, rubbing their noses and cheeks. But as soon as a breeze blows from the west, everything changes. The temperature rises sharply, the sky is covered with a veil, from which millions of snowflakes rush from time to time. Another day and the warming may turn into a thaw. You can play snowballs. All this is the result of the work of air masses brought by the cyclone from the west and heated by the warmth of the Atlantic Ocean. In general, seas and oceans “soften” the climate of the globe, that is, they make its fluctuations less sharp. They humidify the air, stop droughts, reduce frosts in winter and bring coolness on hot days. Seas and oceans regulate the climate. And this is their greatest significance in the phenomena taking place on our planet.
The ability to accumulate heat and then gradually release it to the air is one of the most interesting features of the seas. The study of this feature has made significant progress in recent years as a result of the research of Academician V.V. Shuleikin.
At the same time, the seas and oceans themselves, on their surface and in their depths, quickly respond to phenomena occurring in the atmosphere. If you want to know the sea, first find out what is happening above it.
Whether ice forms in the sea, whether evaporation increases, whether the water is mixed from top to bottom, whether the sea is agitated, whether strong currents arise - all this is the result of the action of air on water.
Our Earth appears to be a blue planet from space. This is because ¾ of the surface of the globe is occupied by the World Ocean. He is united, although greatly divided.
The surface area of the entire World Ocean is 361 million square meters. km.
Oceans of our planet
The ocean is the water shell of the earth, the most important component of the hydrosphere. Continents divide the World Ocean into parts.
Currently, it is customary to distinguish five oceans:
. - the largest and oldest on our planet. Its surface area is 178.6 million square meters. km. It occupies 1/3 of the Earth and makes up almost half of the World Ocean. To imagine this magnitude, it is enough to say that the Pacific Ocean can easily accommodate all the continents and islands combined. This is probably why it is often called the Great Ocean.
The Pacific Ocean owes its name to F. Magellan, who crossed the ocean under favorable conditions during his trip around the world.
The ocean has an oval shape, its widest part is located near the equator.
The southern part of the ocean is an area of calm, light winds and a stable atmosphere. To the west of the Tuamotu Islands, the picture changes dramatically - here is an area of storms and squalls that turn into fierce hurricanes.
In the tropical region, the waters of the Pacific Ocean are clean, transparent and have a deep blue color. A favorable climate developed near the equator. The air temperature here is +25ºC and practically does not change throughout the year. Winds are moderate and often calm.
The northern part of the ocean is similar to the southern part, as if in a mirror image: in the west there is unstable weather with frequent storms and typhoons, in the east there is peace and quiet.
The Pacific Ocean is the richest in the number of animal and plant species. Its waters are home to over 100 thousand species of animals. Almost half of the world's fish catch is caught here. The most important sea routes are laid through this ocean, connecting 4 continents at once.
. occupies an area of 92 million square meters. km. This ocean, like a huge strait, connects the two poles of our planet. The Mid-Atlantic Ridge, famous for the instability of the earth's crust, runs through the center of the ocean. Individual peaks of this ridge rise above the water and form islands, the largest of which is Iceland.
The southern part of the ocean is influenced by trade winds. There are no cyclones here, so the water here is calm, clean and clear. Closer to the equator, the Atlantic changes completely. The waters here are muddy, especially along the coast. This is explained by the fact that large rivers flow into the ocean in this part.
The northern tropical zone of the Atlantic is famous for its hurricanes. Two major currents meet here - the warm Gulf Stream and the cold Labrador Stream.
The northern latitudes of the Atlantic are the most picturesque area with huge icebergs and powerful ice tongues protruding from the waters. This area of the ocean is dangerous for shipping.
. (76 million sq. km) is an area of ancient civilizations. Navigation began to develop here much earlier than in other oceans. The average depth of the ocean is 3700 meters. The coastline is slightly indented, with the exception of the northern part, where most of the seas and bays are located.
The waters of the Indian Ocean are saltier than others because there are far fewer rivers flowing into it. But thanks to this, they are famous for their amazing transparency and rich azure and blue color.
The northern part of the ocean is a monsoon region; typhoons often form in autumn and spring. Closer to the south, the water temperature is lower, due to the influence of Antarctica.
. (15 million sq. km) is located in the Arctic and occupies vast areas around the North Pole. Maximum depth - 5527m.
The central part of the bottom is a continuous intersection of mountain ranges, between which there is a huge basin. The coastline is heavily dissected by seas and bays, and in terms of the number of islands and archipelagos, the Arctic Ocean ranks second after such a giant as the Pacific Ocean.
The most characteristic part of this ocean is the presence of ice. The Arctic Ocean remains the most poorly studied to date, since research is hampered by the fact that most of the ocean is hidden under ice cover.
. . The waters washing Antarctica combine signs. Allowing them to be separated into a separate ocean. But there is still debate about what should be considered boundaries. If the borders from the south are marked by the mainland, then the northern borders are most often drawn at 40-50º south latitude. Within these limits, the ocean area is 86 million square meters. km.
The bottom topography is indented by underwater canyons, ridges and basins. The fauna of the Southern Ocean is rich, with the largest number of endemic animals and plants.
Characteristics of the oceans
The world's oceans are several billion years old. Its prototype is the ancient ocean Panthalassa, which existed when all the continents were still a single whole. Until recently, it was assumed that the ocean floors were level. But it turned out that the bottom, like the land, has a complex topography, with its own mountains and plains.
Properties of the world's oceans
Russian scientist A. Voyekov called the World Ocean a “huge heating battery” of our planet. The fact is that the average water temperature in the oceans is +17ºC, and the average air temperature is +14ºC. Water takes much longer to heat up, but it also consumes heat more slowly than air, while having high heat capacity.
But not all water in the oceans has the same temperature. Under the sun, only surface waters heat up, and with depth the temperature drops. It is known that at the bottom of the oceans the average temperature is only +3ºC. And it remains this way due to the high density of water.
It should be remembered that the water in the oceans is salty, which is why it freezes not at 0ºC, but at -2ºC.
The degree of salinity of waters varies depending on latitude: in temperate latitudes the waters are less salty than, for example, in the tropics. In the north, the waters are also less saline due to the melting of glaciers, which greatly desalinize the water.
Ocean waters also vary in transparency. At the equator the water is clearer. As you move away from the equator, water becomes more quickly saturated with oxygen, which means more microorganisms appear. But near the poles, due to low temperatures, the waters become clearer again. Thus, the waters of the Weddell Sea near Antarctica are considered the most transparent. Second place belongs to the waters of the Sargasso Sea.
The difference between the ocean and the sea
The main difference between the sea and the ocean is its size. Oceans are much larger, and seas are often only part of the oceans. Seas also differ from the ocean to which they belong by a unique hydrological regime (water temperature, salinity, transparency, distinctive composition of flora and fauna).
Ocean climate
Pacific climate Infinitely diverse, the ocean is located in almost all climatic zones: from equatorial to subarctic in the north and Antarctic in the south. There are 5 warm currents and 4 cold currents circulating in the Pacific Ocean.
The greatest amount of precipitation falls in the equatorial belt. The amount of precipitation exceeds the share of water evaporation, so the water in the Pacific Ocean is less salty than in others.
Atlantic Ocean Climate determined by its large extent from north to south. The equator zone is the narrowest part of the ocean, so the water temperature here is lower than in the Pacific or Indian.
The Atlantic is conventionally divided into northern and southern, drawing the border along the equator, with the southern part being much colder due to its proximity to Antarctica. Many areas of this ocean are characterized by dense fogs and powerful cyclones. They are strongest near the southern tip of North America and the Caribbean Sea.
For formation Indian Ocean climate The proximity of two continents - Eurasia and Antarctica - has a huge impact. Eurasia actively participates in the annual change of seasons, bringing dry air in winter and filling the atmosphere with excess moisture in summer.
The proximity of Antarctica causes a decrease in water temperature in the southern part of the ocean. Frequent hurricanes and storms occur north and south of the equator.
Formation climate of the Arctic Ocean determined by its geographical location. Arctic air masses dominate here. Average air temperature: from -20 ºC to -40 ºC, even in summer the temperature rarely rises above 0ºC. But the ocean waters are warmer due to constant contact with the Pacific and Atlantic oceans. Therefore, the Arctic Ocean warms a significant part of the land.
Strong winds are rare, but fog is common in summer. Precipitation falls mainly in the form of snow.
It is influenced by the proximity of Antarctica, the presence of ice and the absence of warm currents. The Antarctic climate prevails here with low temperatures, cloudy weather and gentle winds. Snow falls throughout the year. A distinctive feature of the Southern Ocean climate is high cyclone activity.
The influence of the ocean on the Earth's climate
The ocean has a tremendous influence on climate formation. It accumulates huge reserves of heat. Thanks to the oceans, the climate on our planet becomes softer and warmer, since the temperature of the waters in the oceans does not change as sharply and quickly as the air temperature over land.
The oceans promote better circulation of air masses. And such an important natural phenomenon as the water cycle provides the land with a sufficient amount of moisture.
