Variation of the proportion of precipitation occurring as snow in the Tian Shan Mountains, China

Authors

  • Lingpeng Guo,

    1. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
    2. University of Chinese Academy of Sciences, Beijing, China
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  • Lanhai Li

    Corresponding author
    1. State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, China
    2. Xinjiang Key Laboratory of Water Cycle and Utilization in Arid Zone, Urumqi, China
    • Correspondence to: L. Li, State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi, Xinjiang 830011, China. E-mail: lilh@ms.xjb.ac.cn

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ABSTRACT

Snowfall in mountainous areas provides indispensable water sources for arid and semi-arid watersheds. Changes in snowfall and snowmelt regimes have significantly impacted the water resources' variations and management. This study addresses the ratio of snowfall to precipitation (S/P) in the Tian Shan Mountains, China. It aims to examine changes in S/P ratio and its synchronization with climate change. The results show that the average S/P ratio experienced a downward trend under the precipitation and snowfall increases as well as temperature increases during the cold seasons in 1961–2010. Spatially, the S/P ratios show an increasing trend in the Boertala Valley and the southern slope of the middle Tian Shan Mountains, but a decreasing trend in Yili Valley, and the western and the northern slope of the middle Tian Shan Mountains. The S/P ratios decreased significantly in middle altitudes with elevation ranging from 1500 to 2500 m, but either decreased or increased at elevations below 1500 m due to a temperature inversion in the elevation belt. In high altitudes with elevation over 3500 m, the magnitudes of the decreased S/P ratios were small because the temperature was always below freezing. The decreases in S/P ratio was mainly attributed to the relative changes in snowfall (dS/S) being less than that in precipitation (dP/P), whereas the increases in S/P ratio resulted from the relative changes in snowfall (dS/S) being more than that in precipitation (dP/P). Temperature increases have also lead to the decreases in S/P ratios to some extent.

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