The largest lake in Kyrgyzstan central Asia is the Yssykköl / Issyk-Kul (Kyrgis Ысыккл / Yssykköl "hot lake", also known under the Russian name Иссык-Куль / Issyk-Kul or the Turkish Issık Göl).
After the South American Lake Titicaca, the lake in the Tian Shan Mountains with 6,236 km² area is the second largest mountain lake on earth. It is located in the area Issyk Kul, is 182 cm long, 60 km wide, 668 m deep and is 1,609 m above sea level. The lake is also called the "heart of Tian Shan". North of the lake is the mountain chain of the Kungei-Alatau, to the south is the chain of Terskej-Alatau.
The Yssyk-köl does not freeze despite an air temperature of up to -20 ° C in the winter. This is probably because the rapid mixing between surface water and deep water (with a temperature of> 4 ° C) in the winter prevents the surface from cooling down to the freezing point. In addition, the temperature of the maximum density of the water is reduced from 4 ° C (fresh water) to ≈ 2.6 ° C due to its salt content (approx. 6 g / kg), which makes the water body cooler and thus the feeding more difficult. Other reasons for the absence of an ice cover in winter are often the large depth or the occurrence of warm springs at the bottom of the lake; But these conditions are also fulfilled in other lakes, which still freeze in winter (eg Lake Baikal). The lake has several tributaries but no runoff. For longer periods of time the water level therefore fluctuates strongly due to local climate changes.
The fish-rich still waters are both nature reserves and recreational areas. The towns of Karakol and Cholpon-Ata are located on the shore or near the lake. The lake is also a playground of the novels Tschingis Aitmatows. On the banks of Cholpon-Ata, prehistoric rock drawings were discovered, as well as remains of an old sunken city in Yssyk-köl.
While Kyrgyzstan was associated with the Soviet Union, the lake was used for testing torpedoes and torpedo control systems; Large water and shore areas were military secret and detention zones. In March 2008, the Kyrgyz government announced that 866 hectares of the Karabulan Peninsula would be leased to the Russian navy for an indefinite period, which would resume its military tests there. The lease is to be about 4.5 million US dollars per year.