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75-496: Whether Ouki existed is a subject of controversy. In 2011, scientists claimed that the lake did not exist outside of the Lake Poopo basin. The formation of Ouki is associated with a major glaciation and was probably caused by increased precipitation, which has also been observed elsewhere. Ouki may have reached a water level of approximately 3,735 metres (12,254 ft) with preserved shorelines at Lake Poopó , and it may have covered

150-596: A concentrated belt that stretches east–west except in East China where it is tilted east-northeast over Korea and Japan. The seasonal rain is known as Meiyu in China, Jangma in Korea, and Bai-u in Japan, with the latter two resembling frontal rain. The onset of the summer monsoon is marked by a period of premonsoonal rain over South China and Taiwan in early May. From May through August,

225-410: A dominant westerly component and a strong tendency to ascend and produce copious amounts of rain (because of the condensation of water vapor in the rising air). The intensity and duration, however, are not uniform from year to year. Winter monsoons, by contrast, have a dominant easterly component and a strong tendency to diverge, subside and cause drought. Similar rainfall is caused when moist ocean air

300-598: A few sub-systems, such as the Indian Subcontinental Monsoon which affects the Indian subcontinent and surrounding regions including Nepal, and the East Asian Monsoon which affects southern China, Taiwan , Korea and parts of Japan. The southwestern summer monsoons occur from June through September. The Thar Desert and adjoining areas of the northern and central Indian subcontinent heat up considerably during

375-502: A harmonious system of exchange of goods and services. Other investigators examining the following period, the Early Regional Developments ( c. 300 – 900 AD), have concluded that the size of the inhabited areas increased. The South Poopó inhabitants developed a unique style of ceramics style with triangular spirals. The east portion of the lake has evidence of an important Tiwanaku enclave , with ceramic styles from

450-535: A low pressure system known as a monsoon trough develops over South-East Asia and Australasia and winds are directed toward Australia. In the Philippines, northeast monsoon is called Amihan . The East Asian monsoon affects large parts of Indochina , the Philippines , China, Taiwan , Korea, Japan, and Siberia . It is characterised by a warm, rainy summer monsoon and a cold, dry winter monsoon. The rain occurs in

525-464: A more even temperature, while land temperatures are more variable. During warmer months sunlight heats the surfaces of both land and oceans, but land temperatures rise more quickly. As the land's surface becomes warmer, the air above it expands and an area of low pressure develops. Meanwhile, the ocean remains at a lower temperature than the land, and the air above it retains a higher pressure. This difference in pressure causes sea breezes to blow from

600-573: A shrinking stage of the Ouki lake. Likewise, the existence of Lake Minchin may be in part based on misattributing deposits left by Ouki. The Ouki lake cycle may be subdivided into individual phases in the future. The Ouki lake may have been populated by species such as Pisidium bivalves , ostracodes and the Biomphalaria andecola snail. Waters had a high concentration of strontium . While one model inferred from strontium isotope data assumes that most of

675-620: A weakening of the Leeuwin Current (LC). The weakening of the LC would have an effect on the sea surface temperature (SST) field in the Indian Ocean, as the Indonesian Throughflow generally warms the Indian Ocean. Thus these five intervals could probably be those of considerable lowering of SST in the Indian Ocean and would have influenced Indian monsoon intensity. During the weak LC, there

750-652: Is directly of "cyclonic" (i.e., monsoon-driven) origin (as opposed to " local convection "). The effects also extend westwards to the Mediterranean, where however the impact of the monsoon is to induce drought via the Rodwell-Hoskins mechanism . Around September, with the sun retreating south, the northern landmass of the Indian subcontinent begins to cool off rapidly, and air pressure begins to build over northern India. The Indian Ocean and its surrounding atmosphere still hold their heat, causing cold wind to sweep down from

825-521: Is lifted upwards by mountains, surface heating, convergence at the surface, divergence aloft, or from storm-produced outflows at the surface. However the lifting occurs, the air cools due to expansion in lower pressure, and this produces condensation . The monsoon of western Sub-Saharan Africa is the result of the seasonal shifts of the Intertropical Convergence Zone and the great seasonal temperature and humidity differences between

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900-412: Is one of the so-called deep lake cycles, along with Lake Tauca , from which it may have separated during a period when water levels dropped below 3,700 metres (12,100 ft) altitude. At a locality called Vinto, it has left characteristic tufa deposits which have shapes of inverted cones. The depth of the lake did not exceed c. 80 metres (260 ft). The subsequent Salinas lake cycle may simply be

975-695: Is poorly known, but between 115,000 and 100,000 years ago, the water was higher than 3,720 metres (12,200 ft) elevation. The Ouki stage took place during marine isotope stage 5. Episodes of increased lake size lake level changes coincide with cold periods in the North Atlantic . Alternatively, if radiocarbon dates of 44,609 ± 927 to 33,422 ± 1937 are attributed to Ouki, sediments in the Uyuni basin attributed to Lake Minchin would instead belong to Ouki. Lake Ouki's formation may have been caused by an increase in precipitation, and may be further associated with changes in

1050-577: Is the possibility of reduced intensity of the Indian winter monsoon and strong summer monsoon, because of change in the Indian Ocean dipole due to reduction in net heat input to the Indian Ocean through the Indonesian Throughflow. Thus a better understanding of the possible links between El Niño , Western Pacific Warm Pool, Indonesian Throughflow, wind pattern off western Australia, and ice volume expansion and contraction can be obtained by studying

1125-632: Is unknown whether the Poopó basin lake extended to the Uyuni/Coipasa basins as well. The sill separating the Poopó and Uyuni/Coipasa basins may not have been breached until 80,000–60,000 years ago. In 2013, it was suggested that the "L4" lacustrine stage, which has been identified in drill cores taken from Salar de Uyuni, may be the Ouki/ Salinas lake phase. Lake Poopo Lake Poopó ( Spanish : Lago Poopó Spanish: [ˈlaɣo po.oˈpo] )

1200-602: The Caqilluco landslides, although other researchers did not find an increase in landslide activity there. Accumulation of sediments in the Pativilca valley and fluvial activity at Lima and in the Lomas de Lachay in Peru also coincide with the Ouki humid period. The existence of this lake was questioned in 2011, based on the lack of evidence for such a lake in drill cores of Salar de Uyuni. It

1275-601: The Eemian interglacial, suggests that they had an average duration of around 64 years, with the minimum duration being around 50 years and the maximum approximately 80 years, similar to today. A study of marine plankton suggested that the South Asian Monsoon (SAM) strengthened around 5 million years ago. Then, during ice periods, the sea level fell and the Indonesian Seaway closed. When this happened, cold waters in

1350-727: The Hadley circulation during boreal winter. It is associated with the development of the Siberian High and the movement of the heating maxima from the Northern Hemisphere to the Southern Hemisphere. North-easterly winds flow down Southeast Asia, are turned north-westerly/westerly by Borneo topography towards Australia. This forms a cyclonic circulation vortex over Borneo, which together with descending cold surges of winter air from higher latitudes, cause significant weather phenomena in

1425-603: The Himalayas and Indo-Gangetic Plain towards the vast spans of the Indian Ocean south of the Deccan peninsula. This is known as the Northeast Monsoon or Retreating Monsoon. While travelling towards the Indian Ocean, the cold dry wind picks up some moisture from the Bay of Bengal and pours it over peninsular India and parts of Sri Lanka . Cities like Chennai , which get less rain from

1500-475: The Intertropical Convergence Zone (ITCZ) between its limits to the north and south of the equator. Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern, although technically there is also a dry phase. The term is also sometimes used to describe locally heavy but short-term rains. The major monsoon systems of the world consist of the West African , Asian– Australian ,

1575-682: The North American , and South American monsoons. The term was first used in English in British India and neighboring countries to refer to the big seasonal winds blowing from the Bay of Bengal and Arabian Sea in the southwest bringing heavy rainfall to the area. The etymology of the word monsoon is not wholly certain. The English monsoon came from Portuguese monção ultimately from Arabic موسم ( mawsim , "season"), "perhaps partly via early modern Dutch monson ". Strengthening of

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1650-772: The Sahara and the equatorial Atlantic Ocean. The ITCZ migrates northward from the equatorial Atlantic in February, reaches western Africa on or near June 22, then moves back to the south by October. The dry, northeasterly trade winds , and their more extreme form, the harmattan , are interrupted by the northern shift in the ITCZ and resultant southerly, rain-bearing winds during the summer. The semiarid Sahel and Sudan depend upon this pattern for most of their precipitation. The North American monsoon ( NAM ) occurs from late June or early July into September, originating over Mexico and spreading into

1725-586: The Salar de Uyuni , the Salar de Coipasa and the Lake Poopó area, although the Uyuni and Coipasa basins may rather have been filled by a separate postulated lake, Lake Salinas . Estimates of the surface area depend on the assumed lake levels and whether the lake covered only the Lake Poopó basin or also the Uyuni/Coipasa basins. Estimates range from 10,400–46,500 square kilometres (4,000–18,000 sq mi). The Ouki lake

1800-622: The San Andrés University of La Paz , Bolivia, shows the influence of the Wankarani culture in the Poopó area. Complex central urban areas , such as villages and towns, were developed that expanded into the Poopó basin during the Late Formative period, (200 BC – 200 AD), probably in conjunction with changing patterns of agriculture. Herders and the life style of llama caravan merchants coexisted with more sedentary farmers in

1875-657: The South China Sea led to a timing of the monsoon beginning 15–20 million years ago and linked to early Tibetan uplift. Testing of this hypothesis awaits deep ocean sampling by the Integrated Ocean Drilling Program . The monsoon has varied significantly in strength since this time, largely linked to global climate change , especially the cycle of the Pleistocene ice ages. A study of Asian monsoonal climate cycles from 123,200 to 121,210 years BP, during

1950-604: The return of the westerlies ) is the result of a resurgence of westerly winds from the Atlantic, where they become loaded with wind and rain. These westerly winds are a common phenomenon during the European winter, but they ease as spring approaches in late March and through April and May. The winds pick up again in June, which is why this phenomenon is also referred to as "the return of the westerlies". The rain usually arrives in two waves, at

2025-498: The Andean flamingo and the Andean condor . A total of 17 higher plants and 3 species of algae were identified in and around Lake Poopó. Due to the constant drought and flooding, the littoral zone experienced great disturbances. As a result, there was hardly any vegetation to be found on the shores of the lake. The sparse communities nearby have suffered culturally and financially due to

2100-728: The Asian monsoon has been linked to the uplift of the Tibetan Plateau after the collision of the Indian subcontinent and Asia around 50 million years ago. Because of studies of records from the Arabian Sea and that of the wind-blown dust in the Loess Plateau of China, many geologists believe the monsoon first became strong around 8 million years ago. More recently, studies of plant fossils in China and new long-duration sediment records from

2175-686: The EASM grew in strength, but it has been suggested to have decreased in strength during Heinrich events . The EASM expanded its influence deeper into the interior of Asia as sea levels rose following the LGM; it also underwent a period of intensification during the Middle Holocene, around 6,000 years ago, due to orbital forcing made more intense by the fact that the Sahara at the time was much more vegetated and emitted less dust. This Middle Holocene interval of maximum EASM

2250-579: The East Asian Winter Monsoon (EAWM) became stronger as the subarctic front shifted southwards. An abrupt intensification of the EAWM occurred 5.5 million years ago. The EAWM was still significantly weaker relative to today between 4.3 and 3.8 million years ago but abruptly became more intense around 3.8 million years ago as crustal stretching widened the Tsushima Strait and enabled greater inflow of

2325-499: The GDP and employs 70% of the population) is heavily dependent on the rains, for growing crops especially like cotton , rice , oilseeds and coarse grains. A delay of a few days in the arrival of the monsoon can badly affect the economy, as evidenced in the numerous droughts in India in the 1990s. The monsoon is widely welcomed and appreciated by city-dwellers as well, for it provides relief from

Ouki - Misplaced Pages Continue

2400-799: The Late Holocene, significant glacial accumulation in the Himalayas still occurred due to cold temperatures brought by westerlies from the west. During the Middle Miocene , the July ITCZ, the zone of rainfall maximum, migrated northwards, increasing precipitation over southern China during the East Asian Summer Monsoon (EASM) while making Indochina drier. During the Late Miocene Global Cooling (LMCG), from 7.9 to 5.8 million years ago,

2475-557: The Ouki water was contributed by the Poopó basin, another called "Ouki B" assumes a 69% contribution by waters from Lake Titicaca and no contribution from the Coipasa and Uyuni basins, which is less likely. Waters from the Poopó basin would have spilled into the Uyuni/Coipasa basin. The drying of the lake left deposits containing amphibole , illite , plagioclase feldspar , potassium feldspar, kaolinite , pyroxene , quartz and smectite . Various radiometric dates have been obtained for

2550-498: The Pacific were impeded from flowing into the Indian Ocean. It is believed that the resulting increase in sea surface temperatures in the Indian Ocean increased the intensity of monsoons. In 2018, a study of the SAM's variability over the past million years found that precipitation resulting from the monsoon was significantly reduced during glacial periods compared to interglacial periods like

2625-463: The Poopó basin. These metals are naturally present in the bedrock , from which they are released through weathering processes. The mining activities in the area further contributes to the heavy metal pollution . Acid leaching from mines and mechanical processing of ore speed up the process. The major part of the heavy metals transported to Lake Poopó were immobilized in the bottom sediments. But concentrations of arsenic , lead , and cadmium in

2700-593: The Southwest Monsoon first hits the Western Ghats of the coastal state of Kerala , India, thus making this area the first state in India to receive rain from the Southwest Monsoon. This branch of the monsoon moves northwards along the Western Ghats ( Konkan and Goa ) with precipitation on coastal areas, west of the Western Ghats. The eastern areas of the Western Ghats do not receive much rain from this monsoon as

2775-535: The Southwest Monsoon, receive rain from this Monsoon. About 50% to 60% of the rain received by the state of Tamil Nadu is from the Northeast Monsoon. In Southern Asia, the northeastern monsoons take place from October to December when the surface high-pressure system is strongest. The jet stream in this region splits into the southern subtropical jet and the polar jet. The subtropical flow directs northeasterly winds to blow across southern Asia, creating dry air streams which produce clear skies over India. Meanwhile,

2850-458: The air temperature remains relatively stable for two reasons: water has a relatively high heat capacity (3.9 to 4.2 J g K ), and because both conduction and convection will equilibrate a hot or cold surface with deeper water (up to 50 metres). In contrast, dirt, sand, and rocks have lower heat capacities (0.19 to 0.35 J g K ), and they can only transmit heat into the earth by conduction and not by convection. Therefore, bodies of water stay at

2925-544: The area ecologically sustainable again, with the help of funding from the European Union . But the efforts have been unable to offset other changes: since 1995 regional temperatures have risen and consequently tripled evaporation rates. In addition, water was drawn off for mining and irrigation, compounding the problems. On 20 January 2016 the area was declared a disaster zone by the Bolivian government. The water of Lake Poopó

3000-566: The arrival at the Eastern Himalayas, the winds turns towards the west, travelling over the Indo-Gangetic Plain at a rate of roughly 1–2 weeks per state, pouring rain all along its way. June 1 is regarded as the date of onset of the monsoon in India, as indicated by the arrival of the monsoon in the southernmost state of Kerala. The monsoon accounts for nearly 80% of the rainfall in India. Indian agriculture (which accounts for 25% of

3075-507: The beginning of June, and again in mid- to late June. The European monsoon is not a monsoon in the traditional sense in that it doesn't meet all the requirements to be classified as such. Instead, the return of the westerlies is more regarded as a conveyor belt that delivers a series of low-pressure centres to Western Europe where they create unsettled weather. These storms generally feature significantly lower-than-average temperatures, fierce rain or hail, thunder, and strong winds. The return of

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3150-414: The behaviour of the LC during Quaternary at close stratigraphic intervals. The South American summer monsoon (SASM) is known to have become weakened during Dansgaard–Oeschger events. The SASM has been suggested to have been enhanced during Heinrich events. Monsoons were once considered as a large-scale sea breeze caused by higher temperature over land than in the ocean. This is no longer considered as

3225-648: The cause and the monsoon is now considered a planetary-scale phenomenon involving the annual migration of the Intertropical Convergence Zone between its northern and southern limits. The limits of the ITCZ vary according to the land–sea heating contrast and it is thought that the northern extent of the monsoon in South Asia is influenced by the high Tibetan Plateau. These temperature imbalances happen because oceans and land absorb heat in different ways. Over oceans,

3300-658: The climax of summer heat in June. However, the roads take a battering every year. Often houses and streets are waterlogged and slums are flooded despite drainage systems. A lack of city infrastructure coupled with changing climate patterns causes severe economic loss including damage to property and loss of lives, as evidenced in the 2005 flooding in Mumbai that brought the city to a standstill. Bangladesh and certain regions of India like Assam and West Bengal , also frequently experience heavy floods during this season. Recently, areas in India that used to receive scanty rainfall throughout

3375-399: The colder months, the cycle is reversed. Then the land cools faster than the oceans and the air over the land has higher pressure than air over the ocean. This causes the air over the land to flow to the ocean. When humid air rises over the ocean, it cools, and this causes precipitation over the oceans. (The cool air then flows towards the land to complete the cycle.) Most summer monsoons have

3450-502: The core Titicaca area and surrounding styles, demonstrating the interactions between different peoples in the area. The main inlet of Lake Poopó (roughly 92% of the water) came from the Desaguadero River, which entered the lake at the north end. It flowed south from Lake Titicaca . There were numerous smaller inlets along the eastern shore of the lake, many of which were dry most of the year. At times of very high water levels, Poopó

3525-505: The drainage area. These could also contribute to the salinity of Lake Poopó. The lake body was situated on top of Cenozoic deposits, consisting mainly of unconsolidated material. These sediments are the remains of extensive prehistoric lakes, which covered the Altiplano during at least five glaciation periods. There is a long tradition of mining in the Poopó Basin. Extraction of metals

3600-459: The hot summers. This causes a low pressure area over the northern and central Indian subcontinent. To fill this void, the moisture-laden winds from the Indian Ocean rush into the subcontinent. These winds, rich in moisture, are drawn towards the Himalayas . The Himalayas act like a high wall, blocking the winds from passing into Central Asia, and forcing them to rise. As the clouds rise, their temperature drops, and precipitation occurs . Some areas of

3675-455: The lake had completely dried up, leaving only a few marshy areas. Despite the lake rebounding from two previous recorded drying instances, as of 2016, the lake's recovery is considered unlikely. Suggested causes of the decline are the melting of the Andes glaciers and loss of their waters, because of a drought due to climate change , as well as continued diversion of water for mining and agriculture. Archaeological investigations conducted by

3750-433: The lake water exceeded Bolivian and World Health Organization guideline values for drinking water. There were only three fish species in the system: the native pupfish Orestias agassizii and catfish Trichomycterus rivulatus , and the introduced silverside Odontesthes bonariensis . The lake had a relatively large fish population, but by 2017 pollution and the near-complete reduction of water had all but decimated

3825-469: The locally important fishing industry. The aquatic bird life was very diverse, with a total of 34 species. Most famous are the three species of flamingo ( Andean , James's and Chilean ), which mainly lived in the shallow lagoons in the northern and eastern parts of the lake. An inventory of the bird population, made in 2000 in cooperation with BirdLife International , identified 6 threatened species and others that are near-threatened . Among these are

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3900-529: The loss of the lake, as the local economy was dependent on lake fishing. Additionally, many bird species native to Bolivia and internationally have been affected due to loss of food, and an annual migration area. Monsoon A monsoon ( / m ɒ n ˈ s uː n / ) is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscillation of

3975-444: The monsoon is not a simple response to heating but a more complex interaction of topography, wind and sea, as demonstrated by its abrupt rather than gradual withdrawal from the region. The Australian monsoon (the "Wet") occurs in the southern summer when the monsoon trough develops over Northern Australia . Over three-quarters of annual rainfall in Northern Australia falls during this time. The European Monsoon (more commonly known as

4050-454: The north between approximately 8,000 and 4,000 BP, and most recently retreated southward once more between 4,000 and 0 BP. The January ITCZ migrated further south to its present location during the Middle Miocene, strengthening the summer monsoon of Australia that had previously been weaker. Five episodes during the Quaternary at 2.22 Ma ( PL-1), 1.83 Ma (PL-2), 0.68 Ma (PL-3), 0.45 Ma (PL-4) and 0.04 Ma (PL-5) were identified which showed

4125-413: The ocean to the land, bringing moist air inland. This moist air rises to a higher altitude over land and then it flows back toward the ocean (thus completing the cycle). However, when the air rises, and while it is still over the land, the air cools . This decreases the air's ability to hold water , and this causes precipitation over the land. This is why summer monsoons cause so much rain over land. In

4200-422: The position of the ITCZ and La Nina -like conditions. The increase of precipitation may have amounted to 50–100%. The Ouki lake cycle occurred during a major glaciation that may also be recorded from moraine deposits in the southern Puna , as well as at a time of low summer insolation in the southern hemisphere but with a southward expansion of the South American monsoon . Lake levels in Lake Huinaymarca ,

4275-720: The postulated Ouki paleolake from tufa, wood and fossils of Bulimulidae and Littoridina , mostly within the basin of Lake Poopo. There is noticeable disagreement between radiometric dates obtained by uranium-thorium dating and dates obtained by radiocarbon dating, probably because Ouki is so old that radiocarbon dating becomes unreliable. The former yield ages ranging between 120,000 and 98,000 years ago. The latter produce ages between 45,200 and 28,200 years ago. Radiocarbon dates of such old samples can easily suffer from contamination by modern carbon, creating spuriously young ages. The uranium-thorium dates range between 96,740 ±5,560 and 125,990 ± 9,580 years ago. The exact lake level history

4350-423: The present day. The Indian Summer Monsoon (ISM) underwent several intensifications during the warming following the Last Glacial Maximum, specifically during the time intervals corresponding to 16,100–14,600 BP, 13,600–13,000 BP, and 12,400–10,400 BP as indicated by vegetation changes in the Tibetan Plateau displaying increases in humidity brought by an intensifying ISM. Though the ISM was relatively weak for much of

4425-446: The region. Examples are the formation of a rare low-latitude tropical storm in 2001, Tropical Storm Vamei , and the devastating flood of Jakarta in 2007. The onset of the monsoon over Australia tends to follow the heating maxima down Vietnam and the Malay Peninsula (September), to Sumatra , Borneo and the Philippines (October), to Java , Sulawesi (November), Irian Jaya and northern Australia (December, January). However,

4500-411: The southern basin of Lake Tauca, were low during the proposed Ouki period. Sediments in the Majes River valley indicate humid conditions during the proposed Ouki period, as do lake level records in the Atacama . The humid period in Peru during the Ouki phase may be associated with several large landslides such as the c. 40 cubic kilometres (9.6 cu mi) Chuquibamba landslide complex and

4575-417: The southwest United States by mid-July. It affects Mexico along the Sierra Madre Occidental as well as Arizona , New Mexico , Nevada , Utah , Colorado , West Texas and California . It pushes as far west as the Peninsular Ranges and Transverse Ranges of Southern California, but rarely reaches the coastal strip (a wall of desert thunderstorms only a half-hour's drive away is a common summer sight from

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4650-428: The subcontinent receive up to 10,000 mm (390 in) of rain annually. The southwest monsoon is generally expected to begin around the beginning of June and fade away by the end of September. The moisture-laden winds on reaching the southernmost point of the Indian Peninsula , due to its topography, become divided into two parts: the Arabian Sea Branch and the Bay of Bengal Branch . The Arabian Sea Branch of

4725-423: The summer monsoon shifts through a series of dry and rainy phases as the rain belt moves northward, beginning over Indochina and the South China Sea (May), to the Yangtze River Basin and Japan (June) and finally to northern China and Korea (July). When the monsoon ends in August, the rain belt moves back to southern China. The rainy season occurs from September to February and it is a major source of energy for

4800-483: The sunny skies along the coast during the monsoon). The North American monsoon is known to many as the Summer , Southwest , Mexican or Arizona monsoon. It is also sometimes called the Desert monsoon as a large part of the affected area are the Mojave and Sonoran deserts . However, it is controversial whether the North and South American weather patterns with incomplete wind reversal should be counted as true monsoons. The Asian monsoons may be classified into

4875-445: The surface of Lake Poopó. At this point, the lake volume began to decrease. At its maximum in 1986, the lake had an area of 3,500 km (1,400 sq mi). During the years that followed, the surface area steadily decreased until 1994, when the lake disappeared completely. The time period between 1975 and 1992 was the longest period in recent times when the lake had a continuous water body. Action has been taken in order to make

4950-593: The warm Tsushima Current into the Sea of Japan. Circa 3.0 million years ago, the EAWM became more stable, having previously been more variable and inconsistent, in addition to being enhanced further amidst a period of global cooling and sea level fall. The EASM was weaker during cold intervals of glacial periods such as the Last Glacial Maximum (LGM) and stronger during interglacials and warm intervals of glacial periods. Another EAWM intensification event occurred 2.6 million years ago, followed by yet another one around 1.0 million years ago. During Dansgaard–Oeschger events ,

5025-460: The water increased towards the south. The salinity varied with water volume. During October and November 2006, the salinity in the north end of the lake varied between brackish and saline (15–30,000 mg/L). In the south end of the lake the water was classified as a brine (105,000–125,000 mg/L). The water type was a 4–2 Na-(Mg)-Cl-(SO 4 ). Geological sources of sodium chloride (NaCl), such as halite and feldspars , are present in

5100-425: The wind does not cross the Western Ghats. The Bay of Bengal Branch of Southwest Monsoon flows over the Bay of Bengal heading towards north-east India and Bengal , picking up more moisture from the Bay of Bengal. The winds arrive at the Eastern Himalayas with large amounts of rain. Mawsynram , situated on the southern slopes of the Khasi Hills in Meghalaya , India, is one of the wettest places on Earth. After

5175-407: The year, like the Thar Desert , have surprisingly ended up receiving floods due to the prolonged monsoon season. The influence of the Southwest Monsoon is felt as far north as in China's Xinjiang . It is estimated that about 70% of all precipitation in the central part of the Tian Shan Mountains falls during the three summer months, when the region is under the monsoon influence; about 70% of that

5250-442: Was a large saline lake in a shallow depression in the Altiplano in Oruro Department , Bolivia , at an altitude of approximately 3,700 m (12,100 ft). Due to the lake's length and width (90 by 32 km; 56 by 20 mi), it made up the eastern half of Oruro, known as a mining region in southwest Bolivia . The permanent part of the lake body covered approximately 1,000 square kilometres (390 sq mi) and it

5325-471: Was associated with an expansion of temperate deciduous forest steppe and temperate mixed forest steppe in northern China. By around 5,000 to 4,500 BP, the East Asian monsoon's strength began to wane, weakening from that point until the present day. A particularly notable weakening took place ~3,000 BP. The location of the EASM shifted multiple times over the course of the Holocene: first, it moved southward between 12,000 and 8,000 BP, followed by an expansion to

5400-425: Was connected to the salt desert Salar de Coipasa in the west. A minor outlet led to Salar de Uyuni in the far south of the Altiplano, but as the lake lacks any major outlet, it is classified as an endorheic basin . When the water level of Lake Titicaca was below 3,810 m (12,500 ft), the flow of Desaguadero River was so low it could no longer compensate for the massive water losses due to evaporation from

5475-441: Was highly saline. The salinity was a result of the endorheic nature of the hydrological system on the Altiplano, which allowed all weathered ions to remain in the system. The salinity of Lake Poopó was further increased by the arid climate and the high evaporation from the lake surface. In the northern end of Lake Poopó, dilution of the salinity occurred due to freshwater flow from the Desaguadero River. The salt gradient of

5550-624: Was ordered in the 13th century to support the Inca army. After Spanish colonization in the 16th century, the mining operations increased in scale. At this point the region became known as one of the mining centres of Bolivia. The mining districts are situated at the foothills of the Cordillera Oriental along the eastern border of the Poopó basin. The most important minerals to the economy are silver and tin . Studies have shown elevated concentrations of heavy metals in surface and ground waters of

5625-553: Was the second-largest lake in the country. The lake received most of its water from the Desaguadero River , which flows from Lake Titicaca at the north end of the Altiplano. Since the lake lacked any major outlet and had a mean depth of less than 3 m (10 ft), the surface area differed greatly seasonally. In 2002, the lake was designated as a site for conservation under the Ramsar Convention . By December 2015,

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