Acta Geographica Sinica ›› 2012, Vol. 67 ›› Issue (5): 631-644.doi: 10.11821/xb201205006

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Temporal and Spatial Changes of Precipitation in Qilian Mountains and Hexi Corridor during 1960-2009

JIA Wenxiong   

  1. College of Geography and Environment Science, Northwest Normal University, Lanzhou 730070, China
  • Received:2011-12-12 Revised:2012-02-27 Online:2012-05-20 Published:2012-05-20
  • Supported by:
    National Natural Foundation of China, No.41161017; Natural Foundation of Gansu Province, No.1107RJZA248

Abstract: Based on daily precipitation data of 18 weather stations in Qilian Mountains and Hexi Corridor during 1960 to 2009, the spatial and temporal changes of day number and intensity for different grades of precipitation were analyzed by the methods of linear trend, five-year moving trend, IDW, Morlet wavelet and Mann-Kendall. The results indicated that the spatial distributions of day number and intensity for different grades of precipitation changed from east to west and from south to north. In the last 50 years, the annual variations of day number of different grades of precipitation were increasing in most of the regions and the increasing scales are decreasing from east to west, which is consistent with the intensity of heavy rainfall events. However the annual variations present an increasing trend in some parts or decreasing in other parts in terms of the intensities of light rain, moderate rain and extreme rain. The annual changes of day number of different grades of precipitation showed an increasing trend, and they are significant for light rain, moderate rain and heavy rain. Intensity of light rain and heavy rain prohibited an unobvious decreasing trend, but it is opposite to intensities of moderate rain and extreme rain. The main change cycles of day number of different grades of precipitation have quasi-periods of 2a, 5a, 8a, 11a and 19a, and those of intensity of different grades of precipitation have quasi-periods of 2a, 5a, 11a, 15a and 25a. Except for the abrupt decrease in intensity of light rain, the day number and intensity of different grades of precipitation increased abruptly.

Key words: day number of precipitation, intensity of precipitation, Qilian Mountains, Hexi Corridor