Acta Geographica Sinica ›› 2013, Vol. 68 ›› Issue (11): 1493-1503.doi: 10.11821/dlxb201311005

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Spatial and temporal variations of winter snow over east of Qinghai-Tibet Plateau in the last 50 years

HU Haoran, LIANG Ling   

  1. Institute of Plateau Meterology, CMA, Chengdu 610072, China
  • Received:2013-07-26 Revised:2013-10-08 Online:2013-11-20 Published:2013-11-20
  • Supported by:
    National Natural Science Foundation of China, No.41205068; No.40665003; The research item of Sichuan Meteorological Administration, No.2011-03

Abstract: By using the snow cover days data at 64 weather stations in the east of Qinghai-Tibet Plateau for the period 1961-2010 and the methods of REOF, polynomial fitting, running t-test, linear regression analysis, we analyzed spatial distributions and interdecadal variations of the snow cover days in winter. The results indicate the spatial distribution of the snow cover days in winter is far from uniformity. These regions, located in the Bayan Har Range, Tanggula Range and Nyainqentanggula Range, have rich snowfall and large interannual variability. These regions located in the valley of southern Tibetan Plateau, the dry-hot valley of western Sichuan Plateau and the Qaidam Basin have little snow and small interannual variability. The spatial distributions of the snow cover days in winter in the east of Qinghai-Tibet Plateau are jointly caused by the surrounding atmospheric circulation system and the local complicated terrain. By using polynomial fitting and running t-test methods, we found two abrupt interdecadal changes of winter snow in the east of Qinghai-Tibet Plateau. The first shift that changed from the stage of little snow to the stage of rich snow was observed at the end of the 1980s. The second shift that changed from the stage of rich snow to the stage of little snow occurred more significantly at the end of 20th century. By using linear regression method, we found that snowfall and air temperature in winter had a great effect on winter snow in the east of the plateau, especially the snowfall. The shift of winter snowfall that changed from the little stage to the rich stage at the end of the 1980s is the main cause for the corresponding change of winter snow. The common function about the shift of winter snowfall that changed from the rich stage to the little stage and winter air temperature that changed from the low stage to the high stage at the end of 20th century is the cause for the second shift of winter snow that occurred more significantly.

Key words: spatial distribution, interdecadal variation, winter snow, Qinghai-Tibet Plateau