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Arid Land Geography ›› 2021, Vol. 44 ›› Issue (1): 15-26.doi: 10.12118/j.issn.1000–6060.2021.01.02

• Climatology and Hydrology • Previous Articles     Next Articles

Spatiotemporal variation of snow cover in the Yarkant River Basin during 2002—2018

YI Ying1,2(),LIU Shiyin1,2(),ZHU Yu1,2,WU Kunpeng1,2   

  1. 1. Yunnan Key Laboratory of International Rivers and Transboundary Eco-security, Kunming 650500, Yunnan, China
    2. Institute of International Rivers and Eco-Security Yunnan University, Kunming 650500, Yunnan, China
  • Received:2020-03-24 Revised:2020-10-09 Online:2021-01-25 Published:2021-03-09
  • Contact: Shiyin LIU E-mail:yingyi@mail.ynu.edu.cn;shiyin.liu@ynu.edu.cn

Abstract:

Snow cover is one of the active elements in the cryosphere sensitive to climate changes. Its change can affect the global climate and hydrology changes, and its surface mass and energy balance are affected by the snow-covered days (SCD), snow cover onset dates (SCOD), and snow cover melting dates (SCMD). In this study, we employed the MODIS daily cloud-free snow cover product to calculate variations of snow cover percentage (SCP), SCD, SCOD, and SCMD from July 2002 to June 2018 in the Yarkant River Basin, south Xinjiang, China and then analyzed their distribution and spatiotemporal variations. We discussed the cause of the variation and the relation between the abnormal change of snow cover and ENSO. We found the following results: (1) In the study period, the snow cover area exhibited a slight decrease trend and had a significant negative correlation with temperature and a positive correlation with precipitation. SCP showed a clear linear increase trend with increasing altitude (R²=0.92, P<0.01). When the maximum SCP appears in each altitude zone, the month is generally delayed with the rise in altitude. In contrast, when the minimum SCP appears, the month has no obvious change with altitude (concentrated in August). SCP in spring is less than that in winter when below the 4000 m altitude. On the other hand, SCP in spring is greater than that in winter when above the 4000 m altitude. (2) Clear elevation gradients were found for SCD, SCOD, and SCMD. The spatial distributions of SCD, SCOD, and SCMD are gradually increased, delayed, and advanced, respectively, in a northeast-to-southwest direction in the basin. In the basin, from 2002 to 2018, SCD decreased to 91.9%, SCOD delayed to 65.6%, and SCMD advanced to 77.4%. (3) In 2006, 2008, and 2017, the snow cover area was abnormally large, whereas, in 2010, it was abnormally small, which may be affected by ENSO. (4) High mountains concentrated along the Karakoram, including Parts of the eastern Pamir Plateau, experienced a lengthened SCD, an advanced SCOD, and a delayed SCMD related to the continuous low temperature and the increase of precipitation in spring and autumn.

Key words: Yarkant River Basin, snow covered days, snow cover onset dates, snow cover melting dates