Who owns the Caspian Sea. Territorial division of the lake-sea. Caspian Sea: description, photo and video

The Caspian Sea is simultaneously located on the territory of 5 countries, including not only Russia and Kazakhstan, but also Turkmenistan, Iran and Azerbaijan. This is the world's largest closed reservoir, which has long been characteristic and known to everyone as the sea. But the question is, why is the Caspian Sea called the sea, because in reality it is a lake? And in this situation, we will understand today.

Why is the Caspian Sea called a sea

Despite the fact that this body of water is a lake, it is often called the sea. A significant part of people do not even know that this is a lake. This can be explained very simply, because even at one glance at this reservoir, depicted on the maps, its scale, which is mainly characteristic of the seas, catches the eye. A lake that washes the borders of five countries at once is something unthinkable.

Yes, this is something unthinkable, but it is true, because this is the largest, largest drainless lake in the whole world. And its dimensions are a brief and first reason why it is often called the sea. Moreover, in favor of this lake can be called a sea, the facts also play that there are a little more than 50 islands on its territory. It is noteworthy that some of them are not just medium scale, but truly large dimensions, whose area, imagine, reaches 350 square kilometers.

Why is the Caspian Sea called a lake?

As for the true name of this reservoir, it refers to lakes for a number of reasons. They can be summarized below:

• The bed of the lake is set out by the earth's crust, which has an oceanic type;
• Despite its size and similarity to full-fledged seas, the lake has almost fresh, slightly salty water;
• Almost any sea is part of the oceans, and Caspian lake, due to its geographical location, has no access to the open ocean.

It is also noteworthy that the status of a lake near the Caspian Sea is also confirmed by the fact that its waters are not covered by the UN international regime, and the water area of ​​the lake is divided between the states adjacent to it in a different way than in the case of the seas.

Interestingly, the Caspian Lake is often called not only the Caspian Sea, but also the Caspian. And now, after reading the text of this article, you will surely know that, despite its similarity to the sea, the presence of many properties and characteristics inherent only to the seas, the Caspian is still a lake, and this is a fact.

The Caspian Sea is simultaneously considered both an endorheic lake and a full-fledged sea. The reasons for this confusion are brackish waters and a marine-like hydrological regime.

The Caspian Sea is located on the border of Asia and Europe. Its area is about 370 thousand km 2, the maximum depth is just over one kilometer. The Caspian has a conditional division into three almost equal parts: Southern (39% of the area), Middle (36%) and Northern (25%).

The sea washes simultaneously Russian, Kazakh, Azerbaijani, Turkmen and Iranian shores.

Coast of the Caspian Sea(Caspian) has a length of about 7 thousand kilometers, if you count together with the islands. In the north, the low sea coast is covered with swamps and thickets, and has multiple water channels. The eastern and western coasts of the Caspian have a winding shape, in some places the coasts are covered with limestone.

There are many islands in the Caspian Sea: Dash-Zira, Kyur Dashi, Dzhambaisky, Boyuk-Zira, Gum, Chigil, Khere-Zira, Zenbil, Ogurchinsky, Tyuleniy, Ashur-Ada, etc. Peninsulas: Mangyshlak, Tyub-Karagan, Absheron and Miankale. Their total area equals approximately 400 km 2.

flows into the Caspian Sea more than a hundred different rivers, the most significant are the Ural, Terek, Volga, Atrek, Emba, Samur. Almost all of them provide the sea with 85-95% of the annual runoff.

The largest bays of the Caspian Sea: Kaydak, Agrakhansky, Kazakh, Dead Kultuk, Turkmenbashi, Mangyshlak, Gyzlar, Girkan, Kaydak.

Climate of the Caspian

The Caspian is located in three climatic zones: subtropical climate in the south, continental in the north and temperate in the middle part. in winter average temperature varies from -10 to +10 degrees, while in summer the air warms up to about +25 degrees. During the year falls from 110 mm of precipitation in the east and up to 1500 mm in the west.

The average wind speed is 3–7 m/s, but in autumn and winter it often increases to 35 m/s. The windiest areas are the coastal regions of Makhachkala, Derbent and Absheron Peninsula.

Water temperature in the Caspian Sea fluctuates from zero to +10 degrees in winter, and from 23 to 28 degrees in summer months. In some coastal shallow waters, the water can warm up to 35‒40 degrees.

Only the northern part of the sea is subject to freezing, but in especially cold winters, the coastal zones of the Middle Part are added to it. The ice cover appears in November and disappears only in March.

Problems of the Caspian region

Water pollution is one of the main environmental issues Caspian. Oil production, various harmful substances from flowing rivers, waste from nearby cities - all this adversely affects the state of sea ​​water. Additional troubles are created by poachers, whose actions reduce the number of fish of certain species found in the Caspian Sea.

Sea level rise also causes serious financial damage to all the Caspian countries.

According to conservative estimates, the restoration of destroyed buildings and the implementation of comprehensive measures to protect the coast from flooding costs tens of millions of dollars.

Cities and resorts on the Caspian Sea

The largest city and port washed by the waters of the Caspian Sea is Baku. Among other settlements of Azerbaijan, located in close proximity to the sea, are Sumgayit and Lankaran. On the eastern shores is the city of Turkmenbashi, and about ten kilometers from it by the sea is the large Turkmen resort of Avaza.

On the Russian side, the following cities are located on the seashore: Makhachkala, Izberbash, Derbent, Lagan and Kaspiysk. Astrakhan is also often called a port city, although it is located about 65 kilometers from northern shores Caspian.

Astrakhan

Beach holidays in this region are not provided: along sea ​​coast there are only continuous reed thickets. However, tourists go to Astrakhan not for idle lying on the beach, but for fishing and various types active rest: diving, catamaran, jet skiing, etc. In July and August, excursion boats ply the Caspian.

Dagestan

For a classic seaside vacation, it is better to go to Makhachkala, Kaspiysk or Izberbash - this is where not only good sandy beaches but also decent recreation facilities. The range of entertainment on the seashore from the Dagestan side is quite wide: swimming, therapeutic mud springs, windsurfing, kiting, rock climbing and paragliding.

The only disadvantage of this direction is the underdeveloped infrastructure.

In addition, among some Russian tourists There is an opinion that Dagestan is far from the most peaceful territory that is part of the North Caucasian Federal District.

Kazakhstan

Much more relaxed atmosphere can be found in the Kazakh resorts of Kuryk, Atyrau and Aktau. The last one is the most popular tourist city Kazakhstan: there are many good entertainment venues and well-maintained beaches. In summer, the temperature here is very high, reaching +40 degrees during the daytime, and dropping only to +30 at night.

Disadvantages of Kazakhstan tourist country- the same poor infrastructure and rudimentary transport connection between regions.

Azerbaijan

Baku, Nabran, Lankaran and other Azerbaijani resorts are considered the best places to relax on the Caspian coast. Fortunately, everything is fine with the infrastructure in this country: for example, several modern comfortable hotels with pools and beaches.

However, in order to enjoy relaxing on the Caspian Sea in Azerbaijan, you need to spend a lot of money. In addition, you can get to Baku quickly enough only by plane - trains run rarely, and the journey from Russia itself takes two to three days.

Tourists should not forget that Dagestan and Azerbaijan are Islamic countries, so all "infidels" need to adjust their habitual behavior to local customs.

Subject to simple rules stay, nothing will overshadow your vacation on the Caspian Sea.

The Caspian Sea is the largest drainless lake on the planet. This body of water is called the sea for its huge size, brackish water and sea-like regime. The level of the Caspian Sea-lake lies much lower than the level of the World Ocean. At the beginning of 2000, he had a mark of about - 27 abs. m. At this level, the area of ​​the Caspian Sea is ~ 393 thousand km2 and the volume of water is 78,600 km3. The average and maximum depths are 208 and 1025 m, respectively.

The Caspian Sea is elongated from south to north (Fig. 1). The Caspian washes the shores of Russia, Kazakhstan, Turkmenistan, Azerbaijan and Iran. The reservoir is rich in fish, its bottom and banks are rich in oil and gas. The Caspian Sea is quite well studied, but many mysteries remain in its regime. The most characteristic reservoir - this is the instability of the level with sharp drops and rises. The last rise in the level of the Caspian took place before our eyes from 1978 to 1995. It gave rise to many rumors and speculation. Numerous publications appeared in the press, which spoke about catastrophic floods and ecological catastrophe. It was often written that the rise in the level of the Caspian Sea led to the flooding of almost the entire Volga delta. What is true in the statements made? What is the reason for such behavior of the Caspian Sea?

WHAT HAPPENED TO THE CASPIAN IN THE 20TH CENTURY

Systematic observations over the level of the Caspian Sea were started in 1837. In the second half of the 19th century, the average annual values ​​of the Caspian Sea level were in the range of marks from -26 to -25.5 abs. m and showed a slight downward trend. This trend continued into the 20th century (Fig. 2). In the period from 1929 to 1941, the sea level dropped sharply (by almost 2 m - from - 25.88 to - 27.84 abs. m). In subsequent years, the level continued to fall and, having decreased by approximately 1.2 m, reached in 1977 the lowest mark for the observation period - 29.01 abs. m. Then the sea level began to rise rapidly and, having risen by 2.35 m by 1995, reached a mark of 26.66 abs. m. In the next four years, the average sea level decreased by almost 30 cm. Its average marks were 26.80 in 1996, 26.95 in 1997, 26.94 in 1998 and 27.00 abs. m in 1999.

The decrease in sea level in the years 1930-1970 led to the shallowing of coastal waters, the extension of the coastline towards the sea, and the formation of wide beaches. The latter was perhaps the only positive consequence of the level drop. There were many more negative consequences. With a decrease in the level, the areas of forage land for fish stocks in the northern Caspian have decreased. The shallow estuarine coast of the Volga began to quickly overgrow with aquatic vegetation, which worsened the conditions for the passage of fish to spawn in the Volga. Catches of fish, especially valuable species such as sturgeon and sterlet, have sharply decreased. Shipping began to suffer damage due to the fact that the depths in the approach channels decreased, especially near the Volga delta.

The rise in the level from 1978 to 1995 was not only unexpected, but also led to even greater negative consequences. After all, both the economy and the population coastal areas already adjusted to the low level.

Many sectors of the economy began to suffer damage. Significant territories turned out to be in the zone of flooding and flooding, especially in the northern (flat) part of Dagestan, in Kalmykia and the Astrakhan region. The cities of Derbent, Kaspiysk, Makhachkala, Sulak, Caspian (Lagan) and dozens of other smaller settlements suffered from the level rise. Significant areas of agricultural land have been flooded and flooded. Roads and power lines, engineering structures of industrial enterprises and public utilities are being destroyed. A threatening situation has developed with fish-breeding enterprises. Abrasion processes in the coastal zone and the effect of sea water surges have intensified. In recent years, the flora and fauna of the seaside and coastal zone the Volga delta suffered significant damage.

In connection with the increase in depth in the shallow waters of the Northern Caspian and the reduction in the areas occupied in these places by aquatic vegetation, the conditions for the reproduction of stocks of anadromous and semi-anadromous fish and the conditions for their migration to the delta for spawning have somewhat improved. However, the predominance of negative consequences from the rising sea level made us speak of an ecological catastrophe. The development of measures to protect national economic objects and settlements from the advancing sea began.

HOW UNUSUAL IS CURRENT CASPIAN BEHAVIOR?

Research into the life history of the Caspian Sea can help answer this question. Of course, there are no direct observations of the past regime of the Caspian Sea, but there are archaeological, cartographic and other evidence for historical time and the results of paleogeographic studies covering a longer period.

It is proved that during the Pleistocene (the last 700-500 thousand years) the level of the Caspian Sea underwent large-scale fluctuations in the range of about 200 m: from -140 to + 50 abs. m. In this period of time in the history of the Caspian, four stages are distinguished: Baku, Khazar, Khvalyn and New Caspian (Fig. 3). Each stage included several transgressions and regressions. The Baku transgression occurred 400-500 thousand years ago, the sea level rose to 5 abs. m. During the Khazar stage, there were two transgressions: the early Khazar (250-300 thousand years ago, the maximum level is 10 abs. m) and the late Khazar (100-200 thousand years ago, the highest level is 15 abs. m). The Khvalyn stage in the history of the Caspian included two transgressions: the largest for the Pleistocene period, the early Khvalyn (40-70 thousand years ago, the maximum level is 47 abs. m, which is 74 m higher than the modern one) and the late Khvalyn (10-20 thousand years ago, the rise level up to 0 abs. m). These transgressions were separated by a deep Enotaevskaya regression (22-17 thousand years ago), when the sea level dropped to -64 abs. m and was 37 m lower than the modern one.

Rice. 4. Fluctuations in the level of the Caspian Sea over the past 10 thousand years. P is the natural range of fluctuations in the level of the Caspian Sea under climatic conditions characteristic of the subatlantic epoch of the Holocene (risk zone). I-IV - stages of the New Caspian transgression; M - Mangyshlak, D - Derbent regression

Significant fluctuations in the level of the Caspian also occurred during the New Caspian stage of its history, which coincided with the Holocene (the last 10 thousand years). After the Mangyshlak regression (10 thousand years ago, a level decrease to -50 abs. m), five stages of the New Caspian transgression were noted, separated by small regressions (Fig. 4). Following sea level fluctuations, its transgressions and regressions, the outline of the reservoir also changed (Fig. 5).

Over the historical time (2000 years), the range of changes in the average level of the Caspian Sea was 7 m - from - 32 to - 25 abs. m (see Fig. 4). The minimum level in the last 2000 years was during the Derbent regression (VI-VII centuries AD), when it decreased to - 32 abs. m. During the time that has passed since the Derbent regression, the average sea level has changed in an even narrower range - from -30 to -25 abs. m. This range of level changes is called the risk zone.

Thus, the level of the Caspian has experienced fluctuations before, and in the past they were more significant than in the 20th century. Such periodic fluctuations are a normal manifestation of the unstable state of a closed reservoir with variable conditions at the outer boundaries. Therefore, there is nothing unusual in the lowering and rising of the level of the Caspian Sea.

Fluctuations in the level of the Caspian Sea in the past, apparently, did not lead to the irreversible degradation of its biota. Of course, sharp drops in sea level created temporary unfavorable conditions, for example, for fish stocks. However, with the rise in the level, the situation corrected itself. natural conditions coastal zone (vegetation, benthic animals, fish) experience periodic changes along with fluctuations in sea level and, apparently, have a certain margin of stability and resistance to external influences. After all, the most valuable sturgeon herd has always been in the Caspian basin, regardless of fluctuations in sea level, quickly overcoming the temporary deterioration of living conditions.

Rumors that rising sea levels have caused flooding throughout the Volga Delta have not been confirmed. Moreover, it turned out that the increase in water levels, even in the lower part of the delta, is inadequate to the magnitude of the sea level rise. The increase in the water level in the lower part of the delta during the low water period did not exceed 0.2-0.3 m, and almost did not manifest itself during the flood. At the maximum level of the Caspian Sea in 1995, the backwater from the sea extended along the deepest branch of the Bakhtemir delta by no more than 90 km, and along other branches by no more than 30 km. Therefore, only islands on the seashore and a narrow coastal strip of the delta were flooded. Flooding in the upper and middle parts of the delta was associated with high floods in 1991 and 1995 (which is normal for the Volga delta) and with the unsatisfactory condition of protective dams. The reason for the weak effect of sea level rise on the regime of the Volga delta is the presence of a huge shallow coastal zone, which dampens the effect of the sea on the delta.

With regard to the negative impact of sea level rise on the economy and life of the population in the coastal zone, the following should be recalled. At the end of the last century, the sea level was higher than at present, and this was not perceived as an ecological disaster. And before the level was even higher. Meanwhile, Astrakhan has been known since the middle of the 13th century, and Sarai-Batu, the capital of the Golden Horde, was located here in the 13th - mid-16th centuries. These and many more settlements on the coast of the Caspian Sea did not suffer from high level standing, since they were located on elevated places and at abnormal flood levels or during surges, people temporarily moved from low places to higher ones.

Why, then, are the consequences of a rise in sea level even to smaller levels now perceived as a catastrophe? The cause of the enormous damage that National economy, is not a level rise, but a thoughtless and short-sighted development of a strip of land within the mentioned risk zone, released (as it turned out, temporarily!) From under the sea level after 1929, that is, when the level drops below the mark - 26 abs. m. The buildings erected in the risk zone, of course, turned out to be flooded and partially destroyed. Now, when the territory developed and polluted by man is flooded, a dangerous ecological situation is really created, the source of which is not natural processes, but unreasonable economic activity.

ABOUT THE REASONS FOR THE CASPIAN LEVEL FLUCTUATIONS

Considering the issue of the causes of fluctuations in the level of the Caspian Sea, it is necessary to pay attention to the confrontation in this area of ​​two concepts: geological and climatic. Significant contradictions in these approaches were revealed, for example, at the international conference "Caspian-95".

According to the geological concept, two groups of processes are attributed to the causes of changes in the level of the Caspian Sea. The processes of the first group, according to geologists, lead to a change in the volume of the Caspian depression and, as a result, to changes in sea level. These processes include vertical and horizontal tectonic movements of the earth's crust, accumulation bottom sediments and seismic events. The second group includes processes that, as geologists believe, affect the underground runoff into the sea, either increasing it or decreasing it. Such processes are called periodic extrusion or absorption of water, which saturate bottom sediments under the influence of changing tectonic stresses (changes in periods of compression and tension), as well as technogenic destabilization of the subsoil due to oil and gas production or underground nuclear explosions. It is impossible to deny the fundamental possibility of the influence of geological processes on the morphology and morphometry of the Caspian depression and underground runoff. However, at present, the quantitative relationship of geological factors with fluctuations in the level of the Caspian Sea has not been proven.

There is no doubt that tectonic movements played a decisive role in the initial stages of the formation of the Caspian depression. However, if we take into account that the Caspian Sea basin is located within a geologically heterogeneous territory, which results in a periodic rather than linear nature of tectonic movements with repeated sign changes, then one should hardly expect a noticeable change in the capacity of the basin. Not in favor of the tectonic hypothesis is the fact that the coastlines of the New Caspian transgressions in all sections of the Caspian coast (with the exception of certain areas within the Apsheron archipelago) are at the same level.

There are no grounds to consider the change in the capacity of its basin due to the accumulation of precipitation as the reason for fluctuations in the level of the Caspian Sea. The rate of filling the basin with bottom sediments, among which the main role is played by river discharges, is estimated, according to modern data, at a value of about 1 mm/year or less, which is two orders of magnitude less than the currently observed changes in sea level. Seismic deformations, which are noted only near the epicenter and attenuate at close distances from it, cannot have any significant effect on the volume of the Caspian Basin.

With regard to periodic large-scale unloading groundwater to the Caspian, its mechanism is still unclear. At the same time, this hypothesis is contradicted, according to E.G. Maev, firstly, the undisturbed stratification of interstitial waters, indicating the absence of noticeable migrations of waters through the thickness of bottom sediments, and secondly, the absence of proven powerful hydrological, hydrochemical and sedimentation anomalies in the sea, which should have accompanied a large-scale discharge of groundwater capable of affect changes in water levels.

The main evidence of the insignificant role of geological factors at present is the convincing quantitative confirmation of the plausibility of the second, climatic, or rather, water-balance concept of Caspian level fluctuations.

CHANGES IN THE COMPONENTS OF THE CASPIAN WATER BALANCE AS THE MAIN CAUSE OF ITS LEVEL FLUCTUATIONS

For the first time, fluctuations in the level of the Caspian Sea were explained by changes in climatic conditions (more specifically, river runoff, evaporation and precipitation on the sea surface) by E.Kh. Lenz (1836) and A.I. Voeikov (1884). Later, the leading role of changes in the components of the water balance in sea level fluctuations was again and again proved by hydrologists, oceanologists, physicogeographers and geomorphologists.

The key to most of the studies mentioned is the compilation of the water balance equation and the analysis of its components. The meaning of this equation is as follows: the change in the volume of water in the sea is the difference between the incoming (river and underground runoff, atmospheric precipitation on the sea surface) and outgoing (evaporation from the sea surface and outflow of water into the Kara-Bogaz-Gol Bay) components of the water balance. The change in the level of the Caspian is the quotient of dividing the change in the volume of its waters by the area of ​​the sea. The analysis showed that the leading role in the water balance of the sea belongs to the ratio of the flow of the Volga, Ural, Terek, Sulak, Samur, Kura rivers and visible or effective evaporation, the difference between evaporation and atmospheric precipitation on the sea surface. An analysis of the components of the water balance revealed that the largest contribution (up to 72% of the dispersion) to the level variability comes from the inflow of river waters, and more specifically, the runoff formation zone in the Volga basin. As for the reasons for the change in the flow of the Volga itself, they are associated, as many researchers believe, with the variability of atmospheric precipitation (mainly winter) in the river basin. And the mode of precipitation, in turn, is determined by the circulation of the atmosphere. It has long been proven that the latitudinal type of atmospheric circulation contributes to an increase in precipitation in the Volga basin, while the meridional type contributes to a decrease.

V.N. Malinin found that the root cause of moisture in the Volga basin must be sought in North Atlantic specifically in the Norwegian Sea. It is there that the increase in evaporation from the sea surface leads to an increase in the amount of moisture transferred to the continent, and, accordingly, to an increase in atmospheric precipitation in the Volga basin. The latest data on the water balance of the Caspian Sea, received by the staff of the State Oceanographic Institute R.E. Nikonova and V.N. Bortnik, are given with the author's clarifications in Table. 1. These data convincingly prove that the main reasons for both the rapid drop in sea level in the 1930s and the sharp rise in 1978-1995 were changes in river flow, as well as apparent evaporation.

Keeping in mind that river runoff is one of the main factors affecting the water balance and, as a result, the level of the Caspian Sea (and the Volga runoff provides at least 80% of the total river runoff to the sea and about 70% of the incoming part of the Caspian water balance), it would be interesting to find a connection between sea level and the flow of one Volga, measured most accurately. Direct correlation of these quantities does not give satisfactory results.

However, the relationship between the sea level and the Volga runoff is well traced if the river runoff is not taken into account for each year, but the ordinates of the difference integral runoff curve are taken, that is, the sequential sum of the normalized deviations of the annual runoff values ​​from the long-term average value (norm). Even visual comparison of the course of the average annual levels of the Caspian Sea and the difference integral curve of the Volga runoff (see Fig. 2) makes it possible to reveal their similarity.

For the entire 98-year period of observations of the Volga runoff (the village of Verkhneye Lebyazhye at the head of the delta) and the sea level (Makhachkala), the correlation coefficient of the relationship between the sea level and the ordinates of the difference integral runoff curve was 0.73. If we discard years with small level changes (1900-1928), then the correlation coefficient increases to 0.85. If for analysis we take a period with a rapid decline (1929-1941) and a rise in the level (1978-1995), then the overall correlation coefficient will be 0.987, and separately for both periods 0.990 and 0.979, respectively.

The presented calculation results fully confirm the conclusion that during periods of a sharp decrease or rise in sea level, the levels themselves are closely related to the runoff (more precisely, to the sum of its annual deviations from the norm).

A special task is to assess the role of anthropogenic factors in fluctuations in the level of the Caspian Sea, and above all, the reduction in river flow due to its irretrievable losses for filling reservoirs, evaporation from the surface artificial reservoirs, water intake for irrigation. It is believed that since the 1940s, irretrievable water consumption has been steadily increasing, which has led to a reduction in the inflow of river waters to the Caspian Sea and an additional decrease in its level compared to the natural one. According to V.N. Malinin, by the end of the 1980s, the difference between the actual sea level and the restored (natural) level reached almost 1.5 m. about 26 km3/year). If it were not for the withdrawal of river runoff, then the rise in sea level would have begun not at the end of the 70s, but at the end of the 50s.

The increase in water consumption in the Caspian basin by 2000 was predicted first to 65 km3/year, and then to 55 km3/year (36 of them were in the Volga). Such an increase in irretrievable losses of river runoff should have lowered the level of the Caspian by more than 0.5 m by 2000. In connection with the assessment of the impact of irreversible water consumption on the level of the Caspian, we note the following. First, estimates of water withdrawal volumes and evaporation losses from the surface of reservoirs in the Volga basin found in the literature seem to be significantly overestimated. Secondly, forecasts of water consumption growth turned out to be erroneous. The forecasts included the rate of development of water-consuming sectors of the economy (especially irrigation), which not only turned out to be unrealistic, but also gave way to a decline in production in recent years. In fact, as A.E. Asarin (1997), by 1990 water consumption in the Caspian basin was about 40 km3/year, and has now decreased to 30-35 km3/year (in the Volga basin to 24 km3/year). Therefore, the "anthropogenic" difference between the natural and actual sea levels is currently not as large as predicted.

ON POSSIBLE FLUCTUATIONS OF THE CASPIAN LEVEL IN THE FUTURE

The author does not set himself the goal of analyzing in detail the numerous forecasts of fluctuations in the level of the Caspian Sea (this is an independent and difficult task). The main conclusion from the assessment of the results of forecasting fluctuations in the level of the Caspian can be drawn as follows. Although the forecasts were based on completely different approaches (both deterministic and probabilistic), there was not a single reliable forecast. The main difficulty in using deterministic forecasts based on the sea water balance equation is the lack of development of the theory and practice of ultra-long-term forecasts of climate change over large areas.

When the sea level decreased in the 30-70s, most researchers predicted its further fall. In the last two decades, when sea level rise began, most forecasts predicted an almost linear and even accelerating rise in level to -25 and even -20 abs. m and above at the beginning of the XXI century. In this case, three factors were not taken into account. First, the periodic nature of fluctuations in the level of all endorheic reservoirs. The instability of the Caspian level and its periodic nature are confirmed by the analysis of its current and past fluctuations. Secondly, at sea level close to - 26 abs. m, the flooding of large sor bays on the northeastern coast of the Caspian Sea - Dead Kultuk and Kaydak, as well as low-lying areas in other places of the coast, dried up at a low standing level, will begin. This would lead to an increase in the area of ​​shallow waters and, as a consequence, an increase in evaporation (up to 10 km3/year). With a higher sea level, the outflow of water to Kara-Bogaz-Gol will increase. All this should stabilize or at least slow down the level growth. Thirdly, level fluctuations under the conditions of the modern climatic epoch (the last 2000 years), as shown above, are limited by the risk zone (from -30 to -25 abs. m). Taking into account the anthropogenic decrease in runoff, the level is unlikely to exceed the mark of 26-26.5 abs. m.

The decrease in average annual levels in the last four years by a total of 0.34 m, possibly indicates that in 1995 the level reached its maximum (-26.66 abs. m), and a change in the trend of the Caspian level. In any case, the prediction that sea level is unlikely to exceed 26 abs. m, apparently justified.

In the 20th century, the level of the Caspian Sea changed within 3.5 m, first dropping and then rising sharply. Such behavior of the Caspian Sea is the normal state of a closed reservoir as an open dynamic system with variable conditions at its inlet.

Each combination of incoming (river runoff, precipitation on the sea surface) and outgoing (evaporation from the surface of the reservoir, outflow to the Kara-Bogaz-Gol Bay) components of the Caspian water balance corresponds to its own level of equilibrium. Since the components of the water balance of the sea also change under the influence of climatic conditions, the level of the reservoir fluctuates, trying to reach an equilibrium state, but never reaches it. Ultimately, the trend of changing the level of the Caspian in given time depends on the ratio of precipitation minus evaporation in the watershed (in the basins of the rivers that feed it) and evaporation minus precipitation over the reservoir itself. There is really nothing unusual about the recent rise of the Caspian Sea level by 2.3 m. Such level changes have occurred many times in the past and did not cause irreparable damage to the natural resources of the Caspian. The current rise in sea level has become a catastrophe for the economy of the coastal zone only because of the unreasonable development of this risk zone by man.

Vadim Nikolaevich Mikhailov, Doctor of Geographical Sciences, Professor of the Department of Terrestrial Hydrology of the Faculty of Geography of Moscow State University, Honored Worker of Science of the Russian Federation, full member of the Academy of Water Management Sciences. Area of ​​scientific interests – hydrology and water resources, interaction of rivers and seas, deltas and estuaries, hydroecology. Author and co-author of about 250 scientific papers, including 11 monographs, two textbooks, four scientific and methodological manuals.

February 16th, 2012

Original taken from sibved in the ancient Caspian. Climate catastrophe of the recent past

Looking through ancient maps, I constantly paid attention to how the cartographers of that time depicted the Caspian Sea. On early maps, it has an oval shape, slightly elongated in latitude, in contrast to its modern appearance, where the waters of the Caspian stretch from north to south.

Photos are clickable:

Caspian on the map in modern form

And the size of the Caspian Sea is completely different. The pool area is larger than the modern one.
Let's look at some ancient maps and see for ourselves.

Here the Caspian already has a slightly different shape, but it is still far from modern

All these maps show that the Caspian Sea has a system deep rivers flowing into it along the entire perimeter. Now, the main river flowing into the Caspian is the Volga. With so many rivers in the past, this should be a densely populated, fertile region. The ancient cartographers could not be so mistaken in the geometric shapes of the reservoir and in the number of rivers flowing into it.
I note that not a single map has an image, even a hint of Lake Baikal (this will come in handy later).
Not on maps Aral Sea- it is absorbed by the Caspian, this is one basin.
It is known that the Aral Sea is rapidly drying up, just catastrophically fast. About 25 years ago, the USSR even had projects to save this sea by turning Siberian rivers. Coastline The Aral Sea literally before our eyes, over the years went beyond the horizon.

The official reason for such a catastrophic decrease in the water level in the Aral Sea-Lake is the huge withdrawal of water from the Amudarya and Syrdarya rivers for irrigation of cotton fields.
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Yes, this process is taking place. But not so much. It seems to me that we are witnessing climate change, which began long before the excessive economic activity of man in this region. Many deserts in this region, steppes are the bottom of the ancient Caspian. But not all. Below I will try to explain why.

In the meantime, I will add information from official science confirming changes in the shape and area of ​​the Caspian Basin:

The Russian scientist, academician P.S. Pallas, having visited the low flat shores of the Northern Caspian, wrote that the Caspian steppes are still in such a state, as if they had recently emerged from under the water. This thought comes by itself, if you look at these leveled vast expanses, at this sandy-clay soil mixed with sea shells, and at countless salt marshes. What sea could flood these steppes, if not adjacent to them the Caspian Sea?

Pallas also found traces of a higher standing of the sea on small hills scattered across the Caspian lowland like islands in the middle of the sea. He discovered ledges, or terraces, on the slopes of these hills. They could only be made sea ​​waves operating for a long time.

Soviet scientists have established that on the shores of the Caspian, especially on the eastern (Mangyshlak and others), three coastal terraces are found at a height of 26, 16 and 11 m above the modern level of the Caspian. They belong to the last stage of the Khvalynsk Sea, that is, to the period of 10-20 thousand years ago. On the other hand, there is reliable information about underwater terraces at depths of 4, 8, 12, and 16–20 m below the present level.

At a depth of 16-20 m, there is a sharp bend in the transverse profile of the underwater slope, or, in other words, a flooded terrace. The period of such a low sea level dates back to the post-Khvalynian time. Later, in the Neo-Caspian time, which began 3-3.5 thousand years ago, the level of the Caspian Sea generally increased, reaching a maximum in 1805.

It turns out that in comparatively recent geological time the level of the Caspian experienced significant fluctuations with an amplitude reaching approximately 40 meters.

A large number of coastal ledges - terraces could be formed only during transgressions (the advance of the sea on land) and regressions (retreat of the sea). During transgression, the sea level remained at a certain height for a long time, and the sea surf had time to process the coast, creating beaches and coastal ridges.

Those. scientists do not deny that even in a very recent era by geological standards, the Caspian Sea was different.

Let's read what some figures of the past wrote about the Caspian Sea:

The first information about the Caspian Sea and its shores was found in the writings of ancient Greek and Roman scientists. However, this information received by them from the merchants of the participants in the wars, navigators, was not accurate and often contradicted each other. For example, Strabo believed that the Syr Darya flows simultaneously with two branches into the Caspian Sea and the Aral Sea. In the general geography of Claudius Ptolemy, which was the reference book of travelers until the 17th century, the Aral Sea is not mentioned at all.

The ancient maps of ancient geographers have also come down to us. The distances between geographical points were then determined by the speed and time of movement of caravans and ships, and the direction of the path was determined by the stars.

Herodotus (who lived around 484-425 BC) was the first to define the Caspian as a sea isolated from the ocean with a ratio of its width to length as 1:6, which is very close to reality. Aristotle (384-322 BC) confirmed Herodotus' conclusion. However, many of their contemporaries considered the Caspian northern bay ocean, which surrounded, according to their ideas, all the then known land.

Ptolemy (90-168 AD), like Herodotus, considered the Caspian Sea to be closed, but depicted it incorrectly, in a form approaching a circle.

Later, in 900-1200. AD, Arab scientists, following Ptolemy, represented the Caspian as closed and round. You can go around the Caspian (Khazar) Sea, returning to the place where you started, and not encounter obstacles, except for the rivers flowing into the sea, wrote Istakhari. The same was confirmed in 1280 by Marco Polo, the famous Venetian traveler who visited China. As we shall see below, the misconception about the form of the Caspian persisted in the Western scientific world until the beginning of the 18th century, until it was refuted by Russian hydrographers.
Source: http://stepnoy-sledopyt.narod.ru/geologia/kmore/geol.htm

From all this, it can be concluded that climatic conditions in this region were different, this map of Africa indirectly proves this:

The climate was different not only in Central Asia, but also in the largest desert on the planet - the Sahara. Look at the huge river crossing the modern desert Africa from east to west and into the Atlantic. In addition, a huge number of rivers flow into the Mediterranean Sea and the Atlantic - this indicates heavy rainfall in this region, and at least savannah vegetation. Arabian Peninsula, too, is full of rivers and vegetation.
And this is the climate of the not so distant past, the past, when people made maps to the fullest.

What could have happened that changed Central Asia, northern Africa beyond recognition. Where did so much sand come from in the Karakum and Sahara?

I will put forward a version based on these maps, which at first glance may be incomprehensible:

It can be seen that the Black Sea and the Caspian are connected into one basin and a huge water area flows into them from the northeast and in the center - a huge river flowing from somewhere in the north. There is a connection with the Persian Gulf.

These data are confirmed by scientists:

It turned out that for a very long time, measured in millions of years, the Mediterranean, Black, Azov and Caspian Seas constituted a huge sea basin, connected to the World Ocean. This basin repeatedly changed its outlines, area, depth, was divided into separate parts and restored again.

The stages of development of this basin in the historical sequence received various, purely conditional, names: the Miocene basin, or the sea that existed in the Miocene time, several million years ago, the Sarmatian, Meotic, Pontic, Akchagyl, Apsheron and the Khvalyn Sea closest to our time.
Source: http://stepnoy-sledopyt.narod.ru/geologia/kmore/geol.htm (B.A. Shlyamin. The Caspian Sea. 1954. Geographic survey. 128 p.)

Or this is an image of the post-glacial period, when from the melting of glaciers, water flowed south. But who could draw such accurate map during that period?
Or this is an image of a catastrophe in the very recent past, when the Caspian was at first oval in shape, and then acquired modern look. In any case, there were streams of water, a huge layer of sand and silt was deposited, deserts and steppes were formed in this region.
With Africa, the issue is more complex and requires more complex study.

I will give a good analysis by A. Lorets: “Ancient civilizations were covered with sand” http://alexandrafl.livejournal.com/4402.html which just shows that not so long ago there were cataclysms, information about which is in real history missing. Perhaps St. Petersburg was covered with silt and sand at that time and for this reason, and Peter I and Catherine dug up and restored this ancient city.

One of possible causes what happened could be the fall of a large asteroid into the Arctic Ocean. You can listen to this in this lecture of the "Tynam.net" project "Faroese astrobleme. Star Wound of the Apocalypse":

http://www.youtube.com/watch?v=w4cnp1voABE

it is also possible that many mountain systems formed during this cataclysm. Lake Baikal - too, because. it does not appear on ancient maps. And local rivers are depicted in sufficient detail.

This is how the Mediterranean Sea was formed, which then included the current Azov, Black and Caspian Seas. On the site of the modern Caspian, a huge Caspian lowland, the surface of which was almost 30 meters below the water level in the oceans. When the next rise of land began to take place at the place of formation Caucasus mountains, the Caspian Sea was finally cut off from the ocean, and in its place a closed drainless reservoir was formed, which today is considered the largest inland sea on the planet. However, some scientists call this sea a giant lake.
A feature of the Caspian Sea is the constant fluctuation of the level of salinity of its water. Even in different areas of this sea, the water has different salinity. This was the reason for the predominance of fish and crustaceans in the Caspian Sea, which more easily tolerate fluctuations in water salinity.

Since the Caspian is completely isolated from the ocean, its inhabitants are endermics, i.e. always live in its water area.

The fauna of the Caspian Sea can be conditionally divided into four groups.

The first group of animals includes the descendants of ancient organisms that inhabited Tethys about 70 million years ago. These animals include Caspian gobies (golovach, Knipovich, Berg, bubyr, pugolovka, Baer) and herring (Kessler, Brazhnikov, Volga, brazil, etc.), some mollusks and most crustaceans (long-sexed crayfish, orthemia crustacean, etc.). Some fish, mainly herring, periodically enter the rivers flowing into the Caspian to spawn, many never leave the sea. Gobies prefer to live in coastal waters, often found in estuaries.
The second group of animals of the Caspian Sea is represented by arctic species. penetrated into the Caspian Sea from the north in the postglacial period. These are such animals as the Caspian seal (Caspian seal), fish - Caspian trout, white salmon, nelma. Of the crustaceans, this group is represented by mysid crustaceans, similar to small shrimps, tiny sea cockroaches, and some others.
The third group of animals inhabiting the Caspian includes species that independently or with the help of humans migrated here from the Mediterranean Sea. These are molluscs mitisyaster and abra, crustaceans - amphipods, shrimp, Black Sea and Atlantic crabs and some types of fish: golden mullet (sharp nose), needle fish and Black Sea kalk (flounder).

And, finally, the fourth group - freshwater fish that penetrated into the Caspian Sea from fresh rivers and turned into marine or anadromous, i.e. periodically rising into the rivers. Some of the typically freshwater fish also occasionally enter the Caspian. Among the fish of the fourth group are catfish, pike perch, barbel, red-lipped asp, Caspian fish, Russian and Persian sturgeon, beluga, stellate sturgeon. It should be noted that the Caspian Sea basin is the main habitat of sturgeons on the planet. Almost 80% of all sturgeons in the world live here. Barbels and fish are also valuable commercial fish.

As for sharks and other fish that are predatory and dangerous to humans, they do not live in the Caspian Sea-Lake.