新疆极端降水的气候变化

采用1961～2000年55个气象台站的逐日降水观测资料，分析近40年来新疆极端降水的气候变化、发展趋势和空间分布差异。用Mann-Kendall法对年极端降水量进行突变检验。研究表明：(1) 只有天山北麓经济带和天山南麓国家级棉花基地阿克苏地区极端降水量和频次有显著增多，尤以80年代以后明显，年极端降水量于1980年发生了气候突变，这种气候变化是由夏半年极端降雨量和频次增多导致的。(2) 新疆极端降水强度无显著变化，极端降水频次的显著增多导致极端降水量的显著增多。(3) 极端降水对年总降水量的贡献天山山区占年降水量的41.9%，北疆北部与和田区域极端降水的贡献为17.2%和21.9%，其它区域在25%~31.3%。年极端降水量距平与年降水量距平有好的相关关系 (除阿克苏地区和焉耆盆地外)，说明极端降水量的变化导致年降水量的变化。

Climate Change of Extreme Precipitation in Xinjiang

Based on the day-to-day observed data of precipitation from 55 meteorological stations in Xinjiang from 1961 to 2000, the climatic variations, tendencies and distribution of extreme precipitation have been analyzed during the last 40 years. The climate jumps have been examined in terms of 3-year moving averaged seasonal and annual series of extreme rainfall and frequency using Yamamoto method and Mann-Kendall method. Regional ecological environments have been changed tremendously after large-scale reclamation since the 1950s at the northern foot of the Tianshan Mountains and Aksu area. Rainfall and frequency of extreme precipitation have an increasing tendency in the two areas since the 1980s. Under the special geographical conditions and climate background, the changes resulted from variations of regional eco-environments and climate are induced by human activities. The results obtained are as follows: Quantity and frequency of extreme precipitation have an obvious increasing tendency at the northern foot of the Tianshan Mountains and Aksu area, especially since the 1980s, there is a climate jump of annual extreme precipitation in 1980; the linear tendencies of annual extreme precipitation are 24.5%/10a in Aksu area, 19.5%/10a at the northern foot of the Tianshan Mountains; the linear tendency of frequency increases by 20%/10a in Aksu area, and 14.5%/10a at the northern foot of the Tianshan Mountains. In other areas there are no obvious variations. Climate change of extreme precipitation is from variation of extreme rainfall in summer. The percentage that extreme precipitation takes up in annual precipitation: the Tianshan Mountions is 41.9%, northern Xinjiang and Hotan region are 17.2% and 1.9% respectively, the other areas are 25%-31.3%.