"The woman is created for a man, not a man for a woman" - such a postulate ...
Geographical position and sizes. The Indian Ocean is the third largest pool of the World Ocean, located mainly in the southern hemisphere between Africa, Asia, Australia and Antarctica, which are its natural borders. Only in the south-west and southeast, where the Indian Ocean is widely connected to the Atlantic and Pacific Oceans, the borders are conditionally carried out from the extreme point of Africa - the cape of the needle and Cape South on the island of Tasmania and further to the banks of Antarctica, that is, 20 ° in . in the west and 147 ° c. d.
In the northeast, the Indian Ocean through the Malaccan, Zordsky and Torresov Strait is connected to the Australian-Asian seas. The tight of his border goes from the extreme northern point of Australia - Cape York to the mouth of the Bebel River on New Guinea Island. Next, she turns to the West and the North-West along the Small Stern Islands and Islands of Java, Sumatra and Malacca Peninsula.
The name "Indian" Ocean gave the Portuguese scientist S. Münster in his work "Cosmography" (1555 p.). Ocean's area with seas - 76.17 million km 2, the average depth - 3,711 m, the maximum - 7 209 m, the volume of water - 282.7 million km 3. In the widest place, the ocean extends from the west to the east of Linde Bay To Torresov Strait at 10 ° sh. 11900 km, and from north to south to 60 ° c. D. from Cape Ras Judd to the banks of Antarctica by 10,200 km.
The Indian Ocean is a kind of pool with only inherent in it. Firstly, due to the location of its greater part in the southern hemisphere, a meridional asymmetry of water circulation is characteristic. Secondly, there is a classic monsime atmosphere circulation. Thirdly, civilization originated on his shores, the first state on earth emerged. Modern racial and ethnic complexes that pretended on the ocean shores belong to several "worlds", which, although they interact with each other, but still very different with their historical features and economic and cultural types. Therefore, the ocean attracted and attracts the attention of many researchers.
Islands. Islands in the Indian Ocean little. They are concentrated mainly in the western part and are divided into three genetic types: mainland, volcanic and coral. The mainland belongs to the largest - Madagascar, Sri Lanka, Large Stern, as well as Socotra, Kuria-Wall, Masira and chain of small islands along the shores of Arabia, Indochina and Western Australia. Most of the mainland islands are limestone plateau on older Precambrian granites. But, besides them, with mountainous, compiled by Precambrian breeds. Special structure have the Seychelles. These are the only facilities within the Ocean Lodge, composed of granites.
Seas. Due to the weak dismemberment of the coast in the Indian Ocean, few seas and bays. In the north there are only two seas - Red and Arabian, as well as four large bays - Adensky, Omansky, Persian and Bengali. The edge of the sea - Andaman, Timor, Arafur and Karpenary Bay are located in the east. The southern banks of Australia are washed by the waters of the Great Bay.
Along the shores of Antarctica, the seas are conditionally determined: Risser-Larsen, Cosmonauts, Commonwealth, Davis, Muson, D "Jurville.
By the nature of the structure of the Wpadina of the Indian Ocean, it is divided into four parts: submarine margins of continents, transition zones, mid-oceanic ridges and beds.
According to modern ideas about the origin of the mainland and oceans based on the theory of lithospheric plates, the Indian Ocean began to form at the beginning of the Mesozoic era after the Paleozoic mainland of Gondwan was split into separate parts. The foundation of modern continents of the southern hemisphere - Africa, Antarctica, South America, as well as the Peninsula of Industan - these are part of the ancient mainland Gondwana. At first, the mainland diverged very slowly. Moreover, Australia and Antarctica were still one array. Tens of millions of years have passed, and the width of the Indian Ocean was no more than the modern Red Sea. And only at the end of the Mesozoic era already existed the real ocean, which was washed by the Western coast at the time of the Unified Australia-Antarctic mainland. This mainland existed from a tet of millions of years, while split into two parts. And after that, Antarctica compared to the south relatively quickly.
The bottom of the Indian Ocean is a typical oceanic type bark, consisting of three layers: from above - precipitation and weakly compacted sediments; Below are sedimentary and volcanogenic breeds; Even below - the basalt layer.
The upper layer consists of loose precipitation. Their power varies from several tens of meters to 200 mm, and near the mainland - up to 1.5-2.5 km.
The average layer is considerably compacted, consists mainly of sedimentary rocks and has a power of 1 to 3 km.
The lower (basalt) layer consists of oceanic basalts and has a power of 4-6 km.
An interesting feature of the earth's crust of the Indian Ocean is that it contains areas of the mainland bark, that is, a bark with a granite layer. They go to the surface of the ocean in the form of the islands of Seychelles, Mascarensky, Kergelen and, perhaps, Maldives. As part of these, as marine geologists say, microcontients The power of the earth's crust increases to 30-35 km.
At the bottom of the Indian Ocean, the Mid-Indian Ridge is divided into three parts: Arabian-Indian, West Indian and Central Indian. The latter goes to the Australia-Antarctic raising. All ridges have well-pronounced rift valleys, here are active volcanic and seismic phenomena. The East-Indian ridge, which extends almost in the meridional direction from the Bengal Bay to the Australia-Antarctic Raising, does not have a rift valley compiled by the mountaineed blocks of magmatic rocks, top-covered by the sediment rocks of the Cenozoic era. Education and development of this ridge were not finally studied.
From the bottom of the rift valleys, scientists raised basalts rich in silicon, gabbro, dunits, serpentinites, peridotites and chromiums considered to be a mantle substance.
Probe gutter with a depth of more than 7,700 m similar and origin, and characteristics on the Pacific Gutter.
Relief. Mainland outlook almost everywhere expressed quite clearly. Banks of continents enveling a narrow strip of the shelf. Only in the Persian Gulf, off the coast of Pakistan, Western India, as well as in the Bengal Gulf, in the Andaman, Timor and Arafur seas, the shelf expands to 300-350 km, and in the Bay of Carpenaria - up to 700 km. The monotony of the relief of these sites is broken by coral structures and flooded river valleys.
At a depth of 100-200 m, a steep mainland is formed, dissected by narrow deep canyons, starting mainly in the mouths of the rivers. Especially many of them on the African slope along Kenya and Somalia. Often, the canyons are branched into several sleeves, which are made by river Il. Having settled at the foot of the slope, the ILD forms huge underwater delta merging into the inclined accumulative plain. Especially large cones were formed in the premitten private gang and ind.
Australian slope Unlike African more and complicated by several plateates - Exmut, Naturalist, a cuvette.
The transition zone is expressed only in the northeast. Here is the basin of the Andaman Sea, the inner island arc of the Sunda archipelago, the parallel of the arc is a steep underwater ridge, including the Andaman and Nicobar Islands, and the deep-water zordsky gutter, stretches for 4000 km along the islands of Java and Sumatra from the Small Stern Islands to Myanmar's coast (Burma). In this chute, the maximum depth of the Indian Ocean is 7,729 m. For the transition zone, the eruptions and volcanism are characteristic. In the Zonda Gulf are the island and Volcano Krakataau, which became world famous as a result of his catastrophic explosion in August 1883
The middle ridge is one of the bottom relief forms. The total length of the mid-ocean ridges is about 20,000 km, width - from 150 to 1000 km, height - from 2.5 to 4.0 km.
An important feature of the rift zones of the Mid-Indian spine is their continuation on the mainland. In the western part of the Aden Bay, the fault area branches into two parts. One branch is directed to the north in the form of the Krasnomorsk rift, the second - turns to the West, forming the East African Fault System.
The middle ridge divides the Lodge of the Indian Ocean into three segments: African, Asia-Australian and Antarctic. In each of these segments, a number of other ridges were revealed. Thus, in the center of the Asia-Australian segment above the ocean, a high East-Indian ridge rises, stretched straightly in the meridional direction by more than 5,000 km. This is a narrow handful system with flat vertices. In the south, the latitudinal West Australian ridge is adjacent. It is also a handful, but asymmetrical, with gentle northern and steep southern slopes. The depth of water over its very point is only 563 m. In the northern part of the segment there is a Maldives ridge consisting of a series of plain shallow cans with coral reefs.
The Antarctic segment is distinguished by the spine Kergelen with underwater volcanoes. One of the arrays of this ridge forms a basalt island Kergelen.
In the African segment, high Madagascar and Mascarenic ridges. In addition, Plateau Agullas, the Chase Ridges, Amiranticte Methical Range.
The ocean's bed with a submarine system is divided into large brands. The most important of them is the Central, West-Australian, South Australian, Australia-Antarctic, Madagascar, Mascarenskiy, Mozambique, Somali, Arabian. There are still a number of smaller, and in total in the ocean 24 hollows.
Relief bottom Kotlovin is different. It constitutes predominantly abseed-hilly plains, among which groups of submarine mountains are distinguished. In some babies, the plains of wavy-bugish, such as the plain of Agullas. Flat-resistant plains can be considered the Arabian and central hollows filled with the subtortean gang rivers.
In many basins over the bottom, individual underwater mountains are rising: Athanasius Nikitina, Bardina, Kurchatova, etc.
Climate. In the northern part of the ocean, a decisive role in the formation of the circulation of the atmosphere and climatic features plays a huge array of sushi, which surrounds the ocean from the north. Uneven water heating and sushi contributes to the formation of seasonal baric systems that generate monsoon circulation. The leading role in the formation of seasonal winds is played by South and Southeast Asia. Cyclones do not come here, the air temperature is rarely changing here, which is characteristic of tropical latitudes.
In January, the high-temperature zone is located south of the equator. Eurasian mainland at this time is very cooled, and the area of \u200b\u200bhigh pressure is formed above it. Low pressure is installed over the ocean. Contrasts of temperature and pressure is the cause of the formation of the northeast monsoon. Winter monsoon is much weaker than summer. The average speed is 2-4 m / s. This is due to the fact that the mountain ranges of the Himalayas and Iranian Highlands detain the cold air from the north and limit the development of the northeast wind.
In the spring, the land is quickly heated and the temperature of the air reaches + 40 ° C. The low pressure zone is installed here, due to which the air moves from the sea. Southeast Passat, crossing the equator and hitting the zone of this area, turns to the right, gradually enhances and turns into a south-west monsoon. This relatively stable and strong wind is that the speed of 8-10 m / s, in the Arabian Sea sometimes becomes a storm. The increase in the summer monsoon also contributes to the Himalayas that make the wet air rise. At the same time, a lot of hidden heat from a vaporization is released, which is spent on maintaining monsoon circulation.
Summer Musson begins in June-July, bringing more clouds to India, thunderstorms, storm winds. His lateness or weakening causes drought in India, and excessive precipitation leads to catastrophic floods.
The influence of the African continent on the development of monsoons affects the distance of 800 km. Thanks to the aggregate action of Asia and Africa, the Arabian Sea's water area and part of the ocean zone are covered by monsca.
So, in the northern part of the ocean, two main seasons: warm and quiet winter with a clear sky and a weak northeast monsoon and wet, cloudy, rainy summer with strong storms. This is a classic area of \u200b\u200btropical monsoon.
A completely different atmosphere circulation over the rest of the ocean water area. North of 10 ° sh. Southeast Passat prevails from the subtropical area of \u200b\u200bhigh pressure to equatorial depression. Further south of the Indian maximum between 40 and 55 °. sh. Strong western winds of moderate latitudes blow. The average speed of them8 is 14 m / s, but quite often they will be converted into storms.
One of the important features of atmospheric circulation is constant Western winds in the Equatorial zone of the eastern part of the ocean. According to scientists, these winds arise under the action of a baric minimum, dominating the islands of Indonesia.
The Indian Ocean is characterized by tropical cyclones. They originate most often in the Arabian Sea during the offseason, when the quiet surface of the water is heated to + 30 ° C.
Moving to the north to the shores of India, Pakistan and Bangladesh, they cause great destruction and human sacrifices. The catastrophic consequences had a hurricane in November 1970 p., From which 300 thousand people died. Such hurricanes, but twice as much as they rise in the Bengal bay at the Mascaret Island in the North Coast of Australia.
The air is intensively heated in the equatorial-tropical zone, where the average monthly temperatures reach 27, 32 ° C, and in the north of the Arabian Sea and in Bengal bay - plus 40 ° C. Air here 0.5 1.0 ° C is always colder from water and Only in the fields of the Apwelling warmer.
In high latitudes, the air temperature decreases, in particular in the coastal zone of Antarctica to -50 ° C.
Absolute air humidity corresponds to temperature distribution. The greatest average monthly values \u200b\u200b(32-34 MB) are characteristic of the northern part of the Arabian Sea and the Bengal Bay, the smallest - for the Antarctic zone.
Relative humidity is not below 60% and does not exceed 85%, except for the districts of Antarctica, where it is always above 90%. Regions with oversaturated air is both areas of frequent fogs.
Cloudy and precipitation over the ocean depend on the development of convection and frontal zones. Clearly develops in the internal convection zone. Together with heap-rain clouds, reaching the height of 16 km, layered-cumulus and high-tech clouds are developing here. The latter are often lined up in separate strands for hundreds of kilometers. The sediments are in the form of short-term shower and constitute an average of 2000-3000 mm per year.
In the zone of trade winds and northeastern monsime, the development of clouds at an altitude of 1-2 km is limited to the layer of inversion. Here are typical underdeveloped cumulus clouds of good weather. Precipitation little. At the shores of Arabia in the Red Sea and the Persian Gulf, they do not exceed 100 mm per year. A completely different cloudy is formed over the cold West Australian flow, where instead of cumulus clouds over the surface of the water, thick layered-cumulus clouds without precipitation are hung. Evaporation in these zones exceeds precipitation by 500-1000 mm.
In moderate and high latitudes, cloudy increases dramatically, develop both front and convection clouds, giving precipitation throughout the year. Their number does not exceed 1000-2000 mm. Despite the strong winds, evaporation in a moderate belt is insignificant, because the air is saturated with moisture enough. The sediments are about 500-1000 mm exceed evaporation.
Hydrological features. The movement of water on the surface of the Indian Ocean is due to the action of wind, and at high depth - uneven density distribution. Since the surface waters are mainly mixed in the direction of wind systems, three large-scale circulation are clearly distinguished in the ocean: a monsonic circulation, southern subtropical anticyclonal and antarctic circumpolar flow. The last two systems are similar to the relevant systems of other oceans, but the south subtropical anticyclonal circulation differs from the Pacific and Atlantic because it does not have a clear eastern level along the banks of Australia. At the same time, his Western link is the course of the needle cape - the strongest of such currents of the southern hemisphere. The average speed of its 1 m / s, and in some places reaches 2 m / s.
A composite subtropical anticyclonal cycle in the north is the southern trade in the course of the island of Java emerging in the south and carries water from the Timoral Sea and the Stern Strait to Africa. On the approach to Madagascar island, it is split. Most of the flow continues to move to the West, and the smaller - turns south along the eastern shore of Madagascar. At the shores of South Africa, it merges with the Mozambique course and gives the beginning of the treatment of needle. The latter is a narrow stream of blue water reaches the extreme southern point of Africa.
Having met with the green waters of the Antarctic circumpolar flow, this flow turns back, forming the reverse course of Agully. Thus, in the south of Africa, a small anticyclonal vortex is formed with a width of about 300 km. During the merger of Aguliaskoy the flow with the northern jet of the Antarctic circumpolar flow, a markedly expressed subnutrctic front occurs.
A separate independent vortex, structurally refers to the subtropical circuit, is formed in the Great Australian Bay.
Quite complex circulation in the northern part of the ocean, where monsoon winds are dominated. During the south-western monsoon, the water moves clockwise. The monsoon circulation form three main flows: South Passatom, Somali and Mussonny. During the south-east monsoon, oceanic circulation is less pronounced, and the movement of water is performed counterclockwise. North of the Equator develops a monsonic course of the event, the coast of Somalia turns south.
Between the equator and 8 ° sh. Equatorial countercase is formed through the entire ocean.
The overall pattern of water circulation on the surface of the ocean is preserved to a depth of 200 m with some minor changes associated with the flow drift.
In under surface layers of equatorial latitudes, water is constantly moving to the East in view of the surface equatorial countercurrent, open 1959
At depths of 1000-2000 m, the circulation of water changes from the latitudinal direction to the meridional. The nature of its movement depends on the ranle of the bottom. In the African sector of water move north along the western slopes of Kotlovin, and in the opposite direction - along the eastern. In the Asia-Australian sector, the positive forms of the bottom relief contribute to the development of cyclonic cycles and radiation. Anticyclonic circulation develops in negative forms.
In the water balance of the Indian Ocean, water exchange with the Atlantic and Pacific Oceans is important.
Almost 6 million km of 3 water per year enters the Indian Ocean from the Atlantic and smaller flows through the Antarctic current in the Pacific Ocean. Evaporation exceeds precipitation. These components of the water balance are 115,400 and 84,000 km 3 per year, respectively, so in many places the salinity of water is increased. River stock with continents - 6000 km 3 per year. Even less moisture (540 km 3) comes from mainland ice.
The aqueous masses are formed on the surface of the ocean or come from other places. In the process of direct exchange of energy and substance between the ocean and the atmosphere in the water layer with a thickness of 200-300 m in accordance with the peculiarities of the development of planetary processes, surface waters are formed. Their dynamics and physico-chemical properties have a latitudinal zonality.
Subsurface waters are formed in polar latitudes due to the immersion of supercooled surface waters, and in tropical areas - in the process of immersion of high mineralized waters formed with a large evaporation. The center of formation under surface waters is also the Arabian Sea.
Intermediate waters are formed in the zone of the South Front of Antarctica's surface water. Low-salted and cold water, plunging under warm and salty, move to North almost up to 10 ° C. Sh., carrying a high concentration of oxygen, phosphates, nitrates, organic forms of phosphorus and nitrogen and other mineral substances. At a depth of 500-1000 m, these will face salty red-to-arabic waters with a high concentration of phosphates and nitrates and low oxygen content. Between 5 ° C. sh. and 10 ° sh. The interaction and mixing of these waters with the intermediate waters of the sea of \u200b\u200bthe gang occur. There is a new water mass.
The deep waters are located below 1000 m from the surface. It is believed that they are formed in the northern latitudes of the Atlantic, and penetrate the Indian Ocean from the Atlantic through a wide passage between Africa and Antarctica north of the Polar Front. Raced across the ocean, they change their properties slightly and they fall into the Pacific Ocean.
The bottom aqueous masses are brought from the Antarctic circumpolar flow from the Atlantic Ocean or form on the shelves of the Indo-Ocean sector of Antarctica. Heavy cold and salt waters are lowered by the mainland slope on the bottom and, shimmering through low thresholds of the mid-ocean ridges, are sent to the north almost to the banks of Asia.
The temperature properties of water are subject to the same latitude zonality laws as the air temperature. The average perennial water temperature gradually decreases from the equator to high latitudes. Cold waters off the coast of Antarctica (-1.8 ° C), warm (28 ° C) occupy large spaces along the equator. The highest temperatures have semi-jammed water areas of the Persian Gulf (34 ° C) and the Red Sea (31 ° C). Quite warm (30 ° C) aquatic masses of the Arabian Sea and the Bengal Bay.
The latitudinal temperature distribution is violated in the Somali and Arabian Peninsulas area, where the direction isotherm is the parallel coastline. This anomaly is caused by a raising of deep waters under the action of south-west winds that live along the banks.
The salinity of water depends on the ratio of precipitation and evaporation. In the southern hemisphere of the subtropical region of elevated atmospheric pressure corresponds to a closed area of \u200b\u200belevated salinity (35.8 ‰). In the northern hemisphere, especially in the north-western part of the Arabian Sea, where the evaporation exceeds the amount of precipitation and the amount of flow at 2500 mm, the salinity reaches 36.5, and in semi-cranked water bodies - more than 40. There is a spacious equatorial region of less salinity between these areas of the high salinity (34.5% o), to which the part of the tropical belt is also adjacent to small salinity in the north-east. The smallest salinity (31.5) in the Bengal bay.
Another district of small salinity - Antarctica. During the melting of sea ice and iceberg salinity on the surface decreases to 33.7.
Important physical characteristics of water also its transparency and color. Let transparent water in the southern subtropical region. Between 20 and 36 ° sh. This area reaches 20-40 m. Places - even 50 m. It is a blue water area without vegetation. To the north and south of it, transparency decreases, and the color acquires a greenish tint. Green, as a rule, a sign of organic life.
Organic world. In tropical areas, single-cell algae are common. They are so intensively developing, causing turbidity of water and change its color. In addition, there are many organisms in the ocean, glowing at night. These are some jellyfish, swords and others. We are familiar here of brightly colored sifoforphors, including a poisonous Physie. In moderate latitudes, copes, diatoms, etc. are common.
In the Indian Ocean, three areas of plankton algae. The first of them covers the entire Arabian Sea, Bengal Bay and the Andaman Sea. In each of these water bodies, the distribution of phytoplankton is quite complex. The second area occupies the zone of zone of deep water, stretched through the entire ocean between 5 and 8 ° YU. sh. and is associated with interpassate countercurrent. The third region is the water of Antarctica, among which the zone of the collision of warm and cold waters is characterized by a special productivity.
There are two areas of low productivity (desert) between high performance areas. The first takes a narrow strip in the northern part of the ocean, in the convergence zone, the second is almost the entire central part of the ocean within the anticyclonal circuit. Phytoplankton biomass ranges from 0.1 mg / m 3 in aqueous deserts up to 2,175 mg / m 3 near the island of Java. The main role in the formation of biomass belongs to diatom algae.
The distribution of zooplankton depends on the feed base. Most of it, especially superficial, consumes phytoplankton, therefore, in its distribution, the same pattern, as in the development of phytoplankton. Most of the zooplankton in the waters of Antarctica, Equatorial countercover, the Arabian and Andaman Sea B and Bengal Bay.
The distribution of benthos in general is reminiscent of the distribution of plankton. At the same time, it is characterized by quantity and qualitative composition, is noticeable manifested in the coastal strip. Phytobenthos of tropical areas is characterized by the brown development of the brown (Sargassovo, turbine) and green (caulelemp) algae. Lyingly developing limestone algae - Lithotnia and Khalimeda. They together with corals participate in the formation of reef structures. Special phytocenosis is formed in the coastal zone with mangrove thickets. In moderate latitudes, the most common red (porphyire, helidium) and brown algae, mainly from the Fukusov group and laminarium.
Zoobenthos is represented by various mollusks, limestone and silicon sponges, iglozzy (hedgehogs, starfish, worships, wilderness), numerous crustaceans, hydroes, msanka, coral polyps.
For a tropical zone, very poor and very rich organic world plots are characteristic. The sandy beaches of the continents and islands, well heated by the Sun, but the poor organic substances populated by extremely poor fauna. Also poor benthos or streams of lagoon and the mouth of rivers due to water stagnation and the development of anaerobic processes. At the same time, the Bentos biomass reaches maximum values \u200b\u200b(up to 5-8 kg / m 2) in mangrove thickets. Very high biomass of coral reefs. In areas where corals and the coralobioniv associated fauna are not, the benthos biomass is relatively small (3 g / m 2).
Biomass Zoobenthosus tropical latitudes is an average of 10-15 g / m 2, the phytobenthos is much larger. Sargassov and red algae sometimes give 20 kg, and marine herbs - from up to 7 kg of biomass with 1 m 2.
An important role in the formation of life groups of the Indian Ocean is owned by necton - fish, squid, cetacean and some other groups of oceanic animals. The distribution of non-tonny animals is subject to the latitudinal and circus-continental zonality, and areas rich in fish, squid and cetacean, located in biological areas. More non-attainnants are not near the shores and not in the area of \u200b\u200bAprilling or divergence, but at some distance from them. This is due to the fact that the maximum nucleation of phytoplankton takes place in the zones of deep waters, and its main mass is demolished and here is eaten by the youth zooplankton. Even further, the maximum number of predatory forms of zooplankton is shifted. The same trend is characteristic of necton. In low-productive areas of the open ocean, the number of fish and squid drops sharply. Catto-shaped (coushlots, grand, dolphins) is also very small.
The Indian Ocean ranks third from all over the occupied area. At the same time, compared to others, the greatest depth of the Indian Ocean is quite modest - only 7.45 kilometers.
Location
It is easy to find it on the map - in the north of the ocean there is an Asian part of Eurasia, Antarctica spread out on the southern shores, from the east on the path of flows lies Australia. In the western part there is Africa.
Most of the ocean area spread out in the southern hemisphere. A very conditional line shares Indian and - from in Africa, down the twentieth meridian to the Antarctica itself. From the quietly separated by its Indochinese Peninsula Malacca, the border goes to the north then along the line that connects the islands of Sumatra, Java, Sumba and New Guinea on the map. With the fourth - the Northern Arctic - the Ocean Indian does not have common borders.
Area
The average depth of the Indian Ocean is 3897 meters. At the same time, it covers an area of \u200b\u200b74,917 thousand kilometers, which allows him to be in third place in magnitude among his "counterparts". The shores of this huge reservoir are cut very weak - this is the reason why little seas in its composition.
Relatively little islands lie in this ocean. The most significant of them once broke up from the mainland, so located close to the coastline - Socotra, Madagascar, Sri Lanka. Divided from the shores, in the open part, you can find the islands that originated from volcanoes. It is Croza, Mascarensky and others. In the tropics at the cones of volcanoes there are islands of coral origin, such as Maldives, Coconut, Adaman and others.
The shores in the East and the North-West are indigenous, whereas in the West and the Northeast are mostly apparent. The edge of the coast is cut very weakly, except for its northern part. It is here that most of the big bays focused.
Depth
Of course, on such a large area there can be no equal depth of the Indian Ocean - the maximum is 7130 meters. This point is located in the probe groove. At the same time, the average depth of the Indian Ocean is 3897 meters.
Seafarers and researchers of water spaces cannot be focused on the average number. Therefore, scientists have long been compiled a map of the depths of the Indian Ocean. It is accurately indicated by the bottom height at various points, all shallows, gutters, depressions, volcanoes and other relief features are visible.
Relief
Along the shores, the narrow strip of the mainland shallow is running, a width of about 100 kilometers. The edge of the shelf, located in the ocean, has a small depth - from 50 to 200 meters. Only in the north-west of Australia and along the Antarctic coast, it increases to 300-500 meters. The mainland slope is quite steep, in some places divided by underwater valleys of large rivers, such as Gang, Ind and others. In the northeast, a rather monotonous relief of the bottom of the Indian Ocean is enlivened by the Stern Island Arc. It is here that is located in which the most significant depth of the Indian Ocean is detected. The maximum point of this gutter is located 7130 meters below sea level.
The ridges, trees and mountains broke the bed into several Kotlovin. The most famous - Arabian Both, African-Antarctic and Western Australian. These recesses were formed by hilly, located in the center of the ocean, and accumulative plains, located not far from the continents, in those areas where sedimentary material comes in sufficient quantities.
Among the large number of ridges, East Indian is especially noticeable - its length of about 5 thousand kilometers. However, the relief of the Indian Ocean's bottom has other essential ridges - West Australian, meridional and others. Ornate beds and various volcanoes, places forming chains and even rather large arrays.
The average and oceanic ridges are three branches of the mountain system, dividing the ocean from the center to the north, southeast and south-west. The width of the ridges ranges from 400 to 800 kilometers, the height is 2-3 kilometers. The final of the Indian Ocean in this part is characterized by faults across the ridges. Along them, the bottom is most often shifted horizontally by 400 kilometers.
Unlike the ridges, the Australia-Antarctic raising is a shaft with gentle slopes, whose height reaches a kilometer, the width extends to one and a half thousand kilometers.
Preferably, the tectonic structures of the bottom of this ocean are quite stable. Active developing structures occupy a much smaller area and flow into similar structures of Indochina and East Africa. These main macrostructures are divided into smaller: plates, block and volcanic ridges, banks and coral islands, chute, tectonic ledges, indian ocean and others.
Among the diverse irregularities, the North of the Mascarensky Range occupies a special place. Presumably, this part previously belonged to the long-lost ancient mainland Gondwan.
Climate
The area and depth of the Indian Ocean make it possible to assume that the climate in different parts will be completely different. And indeed it is. The northern part of this huge reservoir has a monsonic climate. In the summer, in a period of reduced pressure over mainland Asia, south-western equatorial air flows predominate over water. In winter, the flow of tropical air masses from the North-West dominate here.
A little south of 10 degrees of southern latitude climate over the ocean becomes much more permanent. In tropical (and subtropical in the summer) latitudes are hosting south-eastern trade winds. In moderate - veneropic cyclones, which move from the West to the East. Often found in the west of tropical latitudes of hurricanes. Most often they roll in summer and autumn.
The air in the north of the ocean is heated in summer to 27 degrees. The African shores are blown by air with a temperature of about 23 degrees. In winter, the temperature decreases depending on the latitude: in the south it can be below the zero mark, while in the northern part of Africa, the thermometer value does not fall below 20 degrees.
The water temperature depends on the flows. Africa's shores are washed by Somali flow, having quite low temperatures. This leads to the fact that the temperature of the water in this region is at about 22-23 degrees. In the north of the ocean, the upper layers of water can reach a temperature of 29 degrees, whereas in the southern regions, the shore of Antarctica, it drops to -1. Of course, we are talking only about the upper layers, since the more the depth of the Indian Ocean, the more difficult it is to draw conclusions about the water temperature.
Water
What is the depth of the Indian Ocean, does not completely affect the number of seas. And they are less than in any other ocean. Mediterranean seas there are only two: the Red and Persian Bay. In addition, there are still the outskirts of the Arabian Sea, Andamansky - closed only partially. In the east of extensive waters are Timor and
The largest rivers in Asia are owned to the pool of this ocean: Gang, Salouin, Brahmaputra, Irvadi, Ind, Eufraate and Tiger. Among African rivers it is worth highlighting Limpopo and Zambezi.
The average depth of the Indian Ocean is 3897 meters. And here in this thicker of water there is a unique phenomenon - a change in the direction of flows. The currents of all other oceans are unchanged from year to year, whereas in Indian flows are subject to winds: in winter they are monsoon, in the summer - prevailing.
Since the deep waters originate in the Red Sea and the Persian Gulf, almost all of the water mass has an increased salinity with a low oxygen percentage.
Shores
In the West and the North-East, predominantly apparent shores, whereas in the North-West and East are indigenous. As already mentioned, the coastline is almost smooth, is cut very weakly almost throughout the length of this water object. The exception is the northern part - it is here that most of the seas belonging to the Indian Ocean basin focuses.
Residents
A sufficiently small average depth of the Indian Ocean can boast of many diverse representatives of the animal and plant worlds. The Indian Ocean is located in the territories of tropical and moderate belts. Shallow water is full of corals and hydrocorages, among which there is a huge number of types of invertebrates. It is worms, and crabs, and sea hedgehogs, stars and other animals. No less brightly colored tropical fish find the shelter in these areas. The coasts are rich in mangrove thickets, in which the orched jumper settled - this fish can live for a very long time without water.
Flora and fauna beaches susceptible to low rich, as the hot sunny rays lie here all the living. In this sense, it is much more diverse: here is a rich selection of algae and invertebrates.
The open ocean is even more rich in living creatures - representatives of both animal and plant worlds.
Major animals are grapening bays. More than a hundred species live in the waters of the Indian Ocean. The glooping mollusks, siphofoforms, jellyfish and other invertebrates are almost not inferior to the number of species. In the waters of the ocean, several types of volatile fish, sharks, glowing anchovies, tuna, sea snakes are known. Whales, lastonodii, sea turtles, Duynes are not less common in these waters.
Pernaya inhabitants are represented by albatrosses, frigates and several types of penguins.
Minerals
In the waters of the Indian Ocean, oil deposits are underway. In addition, the ocean is rich in the ocean and phosphates, the potash raw materials necessary for the fertilizer of agricultural land.
The Indian Ocean has the smallest number of seas compared to other oceans. In the northern part there are the largest seas: Mediterranean - the Red Sea and the Persian Bay, half-plated the Andaman Sea and the outskirts of the Arabian Sea; In the eastern part - Arafur and Timor Sea.
Islands relatively little. The largest of them are mainland and are located near the coast: Madagascar, Sri Lanka, Socotra. In the open part of the ocean there are volcanic islands - Mascarenskie, Cryau, Prince Eduard, and others. In tropical latitudes on volcanic cones, coral islands are towering - Maldives, Lakkadiv, Chagos, Coconut, Most Andaman et al.
Shores on S.-Z. and East are indigenous, on S.-V. And the West predominate apparent. The coastline is risen weakly, with the exception of the northern part of the Indian Ocean, almost all seas and large bays are located here (Adensky, Omansky, Bengali). In the southern part there are Karpenaria Bay, the Big Australian Bay and Spencer Bay, Saint Vincent, etc.
A narrow (up to 100 km) is stretched along the shores (shelf), the external edge of which has a depth of 50-200 m (only Antarctica and North-West Australia to 300-500 m). The mainland slope is a steep (up to 10-30 °) ledge, places dismembered by the submarine valleys of the Rivers of Ind, Gang, et al. In the northeastern part of the ocean, the Zonda island arc and a conjugate zonda flavor, to which the maximum depths are confined (up to 7130 m). The ridges, mountains and shafts of the Indian Ocean bed are divided into a row of Kotlovin, the most significant of which Arabian brand, West-Australian brand, the African Antarctic Basin. The bottom of these kitelins form accumulative and hilly plains; The first are located near the mainland in areas with a plenty of sedimentary material, the second - in the central part of the ocean. Among the numerous ridges of the bed with directness and length (about 5000 km), the Meridional East Indian Range, connecting to Yu, is allocated with the latitudinal West Australian ridge; Large meridional ridges are stretched to Yu. From the Industan Peninsula and about. Madagascar. Widely represented on the bed of the Ocean Volcanoes (Bardina, Shcherbakov, G. Lena, etc.), which in some places form large arrays (to C. from Madagascar) and chains (to V. from Coconut Islands). The average and ocean ridges are a mining system consisting of three branches, divergent from the central part of the ocean at S. (Arabian-Indian Ridge), Yu.-Z. (West Indian and African Antarctic Range) and Yu.-V. (Centralindian ridge and Australia-Antarctic raising). This system has a width of 400-800 km, a height of 2-3 km and the most dismembered by the axial (rift) zone with deep valleys and the boundary rift mountains; The transverse faults are characterized, along which horizontal bottom offsets are noted up to 400 km. The Australia-Antarctic raising, unlike the median ridges, is a more severe shaft with a height of 1 km and a width of up to 1500 km.
The bottom sediments of the Indian Ocean have the highest power (up to 3-4 km) at the foot of the mainland slopes; In the middle of the ocean - a small (about 100 m) power and in places of distribution of the dissected relief - intermittent distribution. The most widely represented foraminiferous (on the mainland slopes, ridges and at the bottom of the majority of Kotlovin at a depth of up to 4,700 m), diatoms (south of 50 ° J. sh.), Radiolari (near the equator) and coral precipitation. Polygenic precipitation - red deep-sea clays - spread south of the equator at a depth of 4.5-6 km and more. Territory precipitation - off the coast of the mainland. Chemogenic precipitates are represented mainly by iron-manganese concretions, and rifogenic - products of destruction of deep breeds. The exits of indigenous rocks are most common on the mainland slopes (sedimentary and metamorphic rocks), mountains (basalts) and mid-ocean ridges, where, in addition to basalts, serpentines, peridotites representing a low-changed substance of the upper mantle of the Earth are found.
For the Indian Ocean, the predominance of stable tectonic structures is characterized both on the bed (Thalassokraton) and in the periphery (mainland platforms); Active developing structures - modern geosyncline (Zonda arc) and georifogenali (mid-oceanic ridge) - occupy smaller areas and are continued in the respective structures of Indochina and rifts of East Africa. These main macrostructures, differ in morphology, the structure of the earth's crust, seismic activity, vulcanism, are divided into smaller structures: plates, usually corresponding to the bottom of oceanic kitelin, block ridges, volcanic ridges, places crowned with coral islands and banks (Chagos, Maldives and others .), Gutter-faults (Chagos, Obi, etc.), often dedicated to the foot of the chill ridges (East-Indian, West-Australian, Maldives, etc.), fault zones, tectonic ledges. Among the structures of the Indian Ocean layer, the northern part of the Muskarensky Range is a special place (according to the presence of continigric rocks - the granites of the Seychelles and the mainland type - the structure, which is apparently part of the ancient mainland Gondwana.
Minerals: On shelves - oil and gas (especially the Persian Bay), monazitic sands (coastal area of \u200b\u200bSouth-Western India), etc.; in rhythic zones - chromium, iron, manganese, copper, and dr.; On the bed - huge accumulations of iron-manganese nodules.
Northern Indian Ocean Musson Climate; In the summer, when the area of \u200b\u200blow pressure develops above Asia, the south-western flow of equatorial air, in winter - the northeastern flow of tropical air are dominated here. South 8-10 ° sh. Atmospheric circulation is much more consistent; Here in tropical (in summer and in subtropical) latitudes, sustainable southeastern trade winds are dominated, and in moderate latitudes - endopic cyclones in the east. In the tropical latitudes in the western part in the summer and autumn there are hurricanes. The average temperature of the air in the northern part of the ocean in the summer is 25-27 ° C, off the coast of Africa to 23 ° C. In the southern part, it decreases in summer to 20-25 ° C at 30 ° YU. sh., up to 5-6 ° C 50 ° sh. and below 0 ° C south of 60 ° sh. In winter, the air temperature varies from 27.5 ° C at the equator to 20 ° C in the northern part, up to 15 ° C to 30 ° YU. sh., up to 0-5 ° С 50 ° sh. and below 0 ° C south of 55-60 ° sh. At the same time, in the southern subtropical latitudes, the temperature in the West under the influence of a warm Madagascar flow by 3-6 ° C is higher than in the east, where there is a cold West Australian current. Cloudy in the monsoon northern part of the Indian Ocean in winter is 10-30%, in summer to 60-70%. In the summer there is also the greatest amount of precipitation. The average annual precipitation on V. Arabian Sea and the Bengal bay of more than 3000 mm, from the equator 2000-3000 mm, in the west of the Arabian Sea to 100 mm. In the southern part of the ocean, the average annual cloudiness is 40-50%, south of 40 ° sh. - up to 80%. The average annual precipitation in subtropics is 500 mm on V., 1000 mm on Z., in moderate latitudes of more than 1000 mm, Antarctica decreases to 250 mm.
The circulation of surface waters in the northern part of the Indian Ocean has a monsime character: in summer - Northeast and Eastern flow, in winter - south-west and west. In the winter months between 3 ° and 8 ° sh. The interpassate (equatorial) countercase develops. In the southern part of the Indian Ocean, the circulation of waters forms an anticyclonal cycle, which is formed from warm currents - southern trade in S., Madagascar and needle in the west and cold - the flow of Western winds in the south and West Australian in the east south of 55 ° YU. sh. Several weak cyclone cycles of water develop, off the coast of Antarctica with the eastern flow.
The thermal balance prevails the positive component: between 10 ° and 20 ° C. sh. 3.7-6.5 GJ / (m2 × year); between 0 ° and 10 ° sh. 1.0-1.8 gd / (m2 × year); between 30 ° and 40 ° sh. - 0.67-0.38 GJ / (m2 × year) [from - 16 to 9 kcal / (cm2 × year)]; between 40 ° and 50 ° sh. 2.34-3.3 gd / (m2 × year); South 50 ° sh. from -1.0 to -3.6 gd / (m2 × year) [from -24 to -86 kcal / (cm2 × year)]. In the consuming part of the thermal balance north of 50 ° sh. The main role belongs to the cost of heat to evaporation, and south of 50 ° sh. - Ocean heat exchange with an atmosphere.
The water temperature on the surface reaches a maximum (more than 29 ° C) in May in the northern part of the ocean. In the summer of the northern hemisphere, it makes it here 27-28 ° C and only at the coast of Africa decreases to 22-23 ° C under the influence of the exit to the surface of cold waters with depths. The equator is equal to 26-28 ° C and decreases to 16-20 ° C to 30 ° YU. sh., up to 3-5 ° С 50 ° sh. and below -1 ° C south of 55 ° sh. In the winter of the northern hemisphere, the temperature on C. is equal to 23-25 \u200b\u200b° C, at an equator 28 ° C, 30 ° YU. sh. 21-25 ° C, 50 ° sh. from 5 to 9 ° C, south of 60 ° sh. Temperatures are negative. In subtropical latitudes all year round in the West, the water temperature is 3-5 ° C higher than in the east.
The saltness of water depends on the water balance, which develops on average for the surface of the Indian Ocean from evaporation (-1380 mm / year), precipitation (1000 mm / year) and mainland (70 cm / year). The main stock of freshwater gives the River South Asia (Gang, Brahmaputra, etc.) and Africa (Zambezi, Limpopo). The greatest saline is celebrated in the Persian Gulf (37-39 ‰), in the Red Sea (41) and in the Arabian Sea (more than 36.5). In the Bengal Gulf and the Andaman Sea, it decreases to 32.0-33.0, in southern tropics - up to 34.0-34.5. In southern subtropical latitudes, saline exceeds 35.5 (maximum 36.5 in summer, 36.0 winter), and south of 40 ° YU. sh. Falls up to 33.0-34.3. The greatest water density (1027) is observed in Antarctic latitudes, the smallest (1018, 1022) is in the northeastern part of the ocean and in the Bengal Gulf. In the northwestern part of the Indian Ocean, the density of water is 1024-1024.5. The oxygen content in the surface layer of water increases from 4.5 ml / l in the northern part of the Indian Ocean to 7-8 ml / l south of 50 ° sh. At the depths of 200-400 m, the absolute size oxygen content is significantly less and varies from 0.21-0.76 on C. up to 2-4 ml / l in the south, at high depths, it is gradually gradually increased in the bottom layer 4.03 -4.68 ml / l. The color of water is predominantly blue, in the Antarctic latitudes of blue, places with greenish shades.
Evils in the Indian Ocean, as a rule, are small (off the shores of the open ocean and on the islands from 0.5 to 1.6 m), only in the vertices of some bays they reach 5-7 m; In Camboi Gulf 11.9 m. These are predominantly semi-sufficient character.
The ice are formed in high latitudes and are taken out by winds and trends together with icebergs in the northern direction (up to 55 ° sh. In August and up to 65-68 ° sh. In February).
The deep circulation and the vertical structure of the Indian Ocean are formed by water immersed in subtropical (subsurface water) and antarctic (intermediate water) of convergence zones and along the continental slope of Antarctica (bottom water), as well as incoming from the Red Sea and the Atlantic Ocean (deep water). The subsurface waters have at a depth of 100-150 m to 400-500 m. The temperature of 10-18 ° C, the saline 35.0-35.7 ‰, intermediate waters occupy a depth of 400-500 m to 1000-1500 m, have a temperature from 4 to 10 ° C, saline 34.2-34,6 ‰; The deep water at a depth of 1000-1500 m to 3500 m have a temperature of 1.6 to 2.8 ° C, saline 34.68-34.78 ‰; Dining water below 3500 m have in the south temperature from -0.07 to -0.24 ° C, saline 34.67-34.69 ‰, on C. - about 0.5 ° C and 34,69-34.77 ‰, respectively.
Flora and fauna
The entire water area of \u200b\u200bthe Indian Ocean lies within the tropical and southern moderate belts. For shallow tropical belts, numerous 6- and 8-beam corals are characterized, hydrocalolls capable of creating islands and atolls together with lime red algae. Among the powerful coral buildings, the richest fauna of various invertebrates (sponges, worms, crabs, mollusks, sea hedgehogs, masters and starfish), small, but brightly painted coral fish. Most of the coasts are occupied by mangrove thickets, which highlights or a fishing fish, a long time to exist in the air. The fauna and flora of the sewing into the tump of beaches and rocks is quantitatively depleted as a result of the depressing effect of sunlight. In a moderate belt, life in such sections of coasts is presented much richer; It develops thick thickets of red and brown algae (laminaries, fukusy, reaching huge sizes of macrocystis), are abundant diverse invertebrates. For open spaces of the Indian Ocean, especially for the surface layer of water thickness (up to 100m), a rich flora is also characteristic. From unicellular planktonal algae, several types of cordial and diatoms of algae predominate, and in the Arabian Sea - cinema algae, often causing so-called water flowering during mass development.
The bulk of the ocean animals make up the contouring rags (more than 100 species), then follow the mollusk, jellyfish, siphofofores, etc. invertebrates. From unicellites are characterized by radolaria; Numerous squid. Several species of volatile fish are most abundant from fish, glowing anchovies - microfids, corneters, large and small tuna, sailboat fish and a variety of sharks, poisonous sea snakes. Sea turtles and large marine mammals are common (dugoni, toothy and toothless whales, laston-either). Among the birds are most characteristic of albatrosis and frigates, as well as several types of penguins, inhabiting the coast of South Africa, Antarctica and Islands lying in a temperate ocean belt.
It has the smallest number of seas. It has a kind of terrain of the bottom, and in the northern part - a special system of winds and seaside flows.
Mostly located in the southern hemisphere between, and. Its coastline is weakly cut, with the exception of the northern and northeastern parts, where there are almost all seas and large bays.
Unlike other oceans, the average and oceanic ridges of the Indian Ocean consist of three branches divergent from its central part. The ridges are dissected by deep and narrow longitudinal depressions - robin. One of these huge rabes - the collapses of the Red Sea, which is a continuation of the faults of the axial part of the Arabian-Indian Mid-Ocean Range.
The average and oceanic ridges are separated by the bed on 3 major areas that are part of three different. The transition from the ocean's bed to the continents is everywhere gradually, only in the northeastern part of the ocean there is an arc of the Sunda Islands, which is immersed by the Indo-Australian lithospheric stove. Therefore, along these islands, a deep-water horror is about 4,000 km long. There are more than a hundred acting volcanoes, among which the famous - Krakataau often occur the earthquakes.
The surface of the Indian Ocean depends on geographic latitude. The northern part of the Indian Ocean is much warmer than South.
In the northern part of the Indian Ocean (north of 10 Yu.Sh.) form monsoons. In the summer, the South-West Summer Musson, carrying a wet equatorial air, in the winter - Northeast Winter Musson, carrying dry tropical air from the sea - Northeast Winter Musson, is blowing.
The system of surface flows in the southern half of the Indian Ocean is similar to a flow system in the corresponding latitudes of the quiet and atlantic oceans. However, north of 10 ° C.Sh. There is a special mode of water movement: monsoon seasonal flows that change the direction to the opposite twice a year appear.
The organic world of the Indian Ocean has a lot in common with the organic world of the quiet and atlantic oceans in the appropriate latitudes. Coral polyps, creating numerous reef buildings, including the islands are common in shallow water of hot belts. Among the fish are the most numerous anchovies, tuna, volatile fish, sailboat fish, sharks. The tropical coasts of the mainland are often engaged in mangrove thickets. They are characterized by peculiar plants with terrestrial respiratory roots and special animal communities (oysters, crabs, shrimps, fish or a jumper). The main mass of animal ocean is invertebrates planktonic organisms. In tropical coastal areas, sea turtles are common, poisonous marine snakes, disappearing mammals - Dujoni. In the cold waters of the southern part of the ocean, whales, coushlots, dolphins, seals live. Among the birds most interesting penguins, inhabiting the coast of South Africa, Antarctica and the islands of the ocean moderate belt.
Natural Wealth and Economic Learning
The Indian Ocean has great biological wealth, but the fishery is mainly limited by coastal zones, where, apart from fish, lobs, shrimps, mollusks are caught. In the open waters of hot belts, tuna is carried out, and in cold - whales, krill.
Of the most important fields of oil and natural gas. Particularly allocated to the Persian bay with the surrounding land, where 1/3 of the Oil of the Foreign World is mined.
In recent decades, the coast of the warm seas and the islands of the northern part of the ocean are becoming increasingly attractive for recreation people, and tourist business is growing burly. Through the Indian Ocean, the volume of transportation is significantly less than through the Atlantic and Pacific Oceans. However, he plays an important role in the development of the countries of South and Southeast Asia.
On the square, the Indian Ocean ranks third after the quiet and Atlantic. The average depth is about 4 km., And the maximum is registered in the Javanese groove and is 7,729 m.
The Indian Ocean ishes the coast of the oldest foci of civilization and it is believed that it was he who began to explore the very first. The routes of the first swimming pools did not go far into open waters, so the ancients who lived on the shore of the ocean, considered him just the huge sea.
The Indian Ocean seems the most densely populated among animals. Fish reserves at all times were famous for their abundance. The northern waters served almost the only source of food for people. Pearls, diamonds, emeralds and other precious stones - all this is in the Indian Ocean.
Rich Ocean and minerals. In the Persian Gulf is one of the largest oil deposits developed by man.
The Indian Ocean flows a small number of rivers, mainly in the north. These rivers carry in the ocean a lot of sedimentary breeds, so this part of the ocean can not boast of cleanliness. Otherwise, things are in the south, where the ocean does not have freshwater arteries. Water seems to be observing crystal clear, with a dark blue tide.
The lack of sufficient desalination, as well as a large evaporation explains why the salinity of water in it is slightly higher, compared with other oceans. The most salty plot of the Indian Ocean is the Red Sea (42%).
Climate
Since the Indian Ocean has extensive borders with the mainland, the climatic conditions are largely determined by the surrounding land. Overaced status " mussonsky". Pressure contrast over land and over the sea causes strong winds - mussons. In the summer, when the land in the north of the ocean is severely heated, there is a large area of \u200b\u200blow pressure, causing abundant precipitation both above the mainland and above the ocean. This is the so-called " southwest Equatorial Musson".
On the contrary, the winter is characterized by more sharp weather in the form of destructive hurricanes and floods on land. High pressure area over Asia causes trade winds.
The speed of monsoons and trade winds is so big that they form large surface trends that change each season. The largest flow of Somaliwhich in winter flows from the north to south, and in the summer changes its direction.
The Indian Ocean is warm enough. The temperature of the water surface in Australia reaches 29 degrees, but in the subtropics it is colder, in the area 20. A minor, but quite a tangible effect on the water temperature, as well as its salinity, have icebergs that can swim quite high, up to 40 degrees of southern latitude . Before this area salinity on average - 32% and rises closer to the north.
