1965-2015年新疆夏季不同等级降水的空间分布特征

根据新疆51个台站1965-2015年夏季逐日降水资料，将降水划分为小雨、中雨及大雨3个等级，分析了新疆近51 a夏季不同等级降水量、降水日数及降水强度的空间分布特征，并讨论了各等级降水日、降水量及降水强度与总降水量的空间相似程度以及各等级降水对夏季总降水的贡献。结果表明：新疆降水主要集中在夏季，并以小雨为主。以天山山脉为界，南北两疆降水空间分布存在明显差异，北疆夏季降水量（日）占年降水量（日）的36%~45%（36%~39%），南疆夏季降水量（日）占年降水量（日）的51%~63%（48%~60%）；新疆夏季不同等级降水量、降水日及降水强度的空间分布不均匀。新疆夏季总降水量与各等级降水量的空间相似系数最为密切，与各等级降水强度的空间相似系数相对较小；新疆夏季小雨贡献率最大，中雨其次，大雨最小，夏季降水量和降水日的变化主要受小雨的影响。

Spatial distribution of summer graded precipitation in Xinjiang during 1965-2015

According to the daily precipitation data collected from 51 stations in Xinjiang during the recent 51 years (1965-2015), the precipitation intensity can be classified into three levels:light rain; moderate rain and heavy rain. The spatial patterns of the three-level precipitation amounts, precipitation days, and precipitation intensity during summers of the 51 years in the area were analyzed, we discuss their spatial pattern differences of total precipitation through spatial correlation coefficient calculation and the contribution of precipitation at different levels to summer total precipitation. Results show as follows:(1) The precipitation occurred most frequently in summer, and the light rain was the major of this area. Taking Tianshan Mountains as the boundary, there was significant differences in the spatial distribution of precipitation in the north and south Xinjiang, the summer precipitation amounts (precipitation days) in North Xinjiang accounted for 36%~45% (36%~39%) of annual precipitation amounts(precipitation days), and in South Xinjiang accounted for 51%~63% (48%~60%) of annual precipitation amounts (precipitation days); (2) The spatial distribution of amount, days and intensity for different grades of precipitation in Xinjiang were uneven. The spatial correlation coefficient of summer total precipitation and the precipitation amounts of each grades was most closely, with the precipitation intensity of each grades were relatively poor; (3) The contribution rate of Xinjiang summer precipitation mainly was light rain, the moderate rain took the second place, and the heavy rain ranked the third. The change of precipitation amounts and precipitation days in summer was mainly affected by light rain.