Climatic Influences on Water Resources Formation and Conversion in Arid Region of Northwest China.

Climate change and water resources have been drawn wide attention by the government, academic field and the public. The arid region of Northwest China is a special natural unit, accounting for about 1/4 of the entire land area of China, which has very fragile water system and responds sensitively to the global climate change. Based on the previous research results, this report analyzes the impacts of climate change on water resources formation and conversion, water cycle process and ecological security in the arid region of Northwest China, which includes: In the past half century, the temperature of the arid northwest region has increased at a rate of 0.33–0.39°C/10a,higher than the global average, the trend experienced a sharp increase in 1997, making the two decades the warmest period. The winter temperature increased the most obviously and mainly caused by changes in Siberian High. The precipitation exhibited a general upward tendency, however, precipitation in desert areas showed inconspicuous change, about 35% sites of precipitation had decreasing trend in this region since 2000. The mountain glaciers melt and retreat has been accelerated by climate change, particularly by the impact of winter temperature. The runoff of the northwest arid area strongly depends on glaciers (snow). Specifically, with the intensification of warming and extreme hydrological events, changes in glacier water resources will become increasingly complicated. In the Tarim River Basin, the proportion of glacier melt water to runoff is high (e.g., as much as 50%) and it is supposed that the runoff may show a great fluctuation in the near future. In the arid region, water resource is a key factor restricting socio-economic development and affecting ecological security. Therefore, it is necessary to enhance the water resources system in arid region of northwest to address climate change and allocate limited water resources rationally.