阿勒泰地区冬季降水变化特征分析

利用阿勒泰地区7个地面气象站1961—2011年51a的降水观测资料，运用线性趋势、变差分析、EOF、Molet小波变换、M—K突变检测、R／S分析法，分析了该地区近50a来冬季降水的时空变化特征。结果表明：近50a来，该地区冬季降水量存在自山区向河谷逐渐减少的分布特征，年际变化幅度由东北向西南逐渐减小；在空间分布上以全地区一致型为主，部分年份还呈现东北一西南差异分布。冬季降水量在196l一1968年处于偏多阶段，1968--1982年为偏少阶段，此后呈增多趋势。该地区降水以18a周期变化为主，20世纪70年代中后期出现8a的短周期，在90年代中期出现5a的短周期振荡。冬季降水量的突变特征并不显著。R／S分析表明该地区冬季降水量的增加趋势在未来仍将持续。

Analysis of Winter Precipitaion Variation Characeristic in Aletay Area

Based on 7 representative weather stations in Aletay from 1961 to 2010,this paper studied the winter precipitation using trend coefficient, differential analysis, Empirical Orthogonal Function, Morlet wavelet transformation, sharp change check and R/S analysis. We analyzed the winter precipitation spatial-temporal distribution, change trend and abrupt break. The result shows as follows, the winter precipitation gradually decreased from mountainous area to river vale and yearly precipitation gradually decreased from Northeast to Southwest in Altay region during the 50 years. For spatial distribution,the winter precipitation mainly presented uniformity, but in a few years, the precipitation varied from the northeast to the southwest. On the whole, the winter precipitation was above normal from 1961 to 1968 and was below normal from 1968 to 1982, and afterwards the precipitation increased fluctuantly. The precipitation showed an obvious long cycle of 18 years,8 years short cycle during the late middle period of the 1970s, 5 years short cycle in the middle period of the 1990s. The winter precipitation did not exhibit abrupt change. The R/S analysis shows that the winter precipitation increasing trend in the Altay area during the past 50 years will last in the future.