Changes in Central Asia’s Water Tower: Past, Present and Future

Abstract

The Tienshan Mountains, with its status as “water tower”, is the main water source and ecological barrier in Central Asia. The rapid warming affected precipitation amounts and fraction as well as the original glacier/snowmelt water processes, thereby affecting the runoff and water storage. The ratio of snowfall to precipitation (S/P) experienced a downward trend, along with a shift from snow to rain. Spatially, the snow cover area in Middle Tienshan Mountains decreased significantly, while that in West Tienshan Mountains increased slightly. Approximately 97.52% of glaciers in the Tienshan Mountains showed a retreating trend, which was especially obvious in the North and East Tienshan Mountains. River runoff responds in a complex way to changes in climate and cryosphere. It appears that catchments with a higher fraction of glacierized area showed mainly increasing runoff trends, while river basins with less or no glacierization exhibited large variations in the observed runoff changes. The total water storage in the Tienshan Mountains also experienced a significant decreasing trend in Middle and East Tienshan Mountains, but a slight decreasing trend in West Tienshan Mountains, totally at an average rate of −3.72 mm/a. In future, water storage levels are expected to show deficits for the next half-century.

Re-establishing glacier monitoring in Kyrgyzstan and Uzbekistan, Central Asia

“…The same authors indicate an unequivocal change in precipitation across a few stations in the central Tien Shan. A decrease in snow cover has been observed for the period from 1960 to 2007 in the entire Tien Shan (Chen et al, 2016). Precipitation changes seem to be less important.…”

Mass balance observations and reconstruction for Batysh Sook Glacier, Tien Shan, from 2004 to 2016

“…The total water storage of the Tien Shan has a strong decreasing trend with an annual average of − 3.72 mm a − 1 (Chen et al, 2016). This trend is expected to increase in future, leading to an important water shortage for the next half-century (Chen et al, 2016).…”

“…This trend is expected to increase in future, leading to an important water shortage for the next half-century (Chen et al, 2016). Considering the major contribution of fresh water stored in the Kyrgyz Mountains, a detailed understanding of the evolution of Tien Shan glaciers as an important component of the cryosphere is of crucial interest.…”

Snowmelt Water Alters the Regime of Runoff in the Arid Region of Northwest China

“…The air temperature in mountainous areas has experienced a sharp increase over the past half-century [7,8], accompanied by accelerated snow and glacier melting as a consequence. Many studies have revealed the significant trend of glacier/snow-cover shrinkage and snowline rising occurring in Tienshan Mountains [9][10][11], and half of its total glacier volumes will catchments ranges from 298 km 2 to 43,343 km 2 , and the elevation ranges from 1049 m to 4638 m. The annual precipitation varies from 118 mm to 778 mm, and the annual pan evaporation is from 560 mm to 1202 mm. The ratio of annual runoff to precipitation across 64 catchments ranges is from 0.10 to 2.04, with an average value of 0.59.…”