新疆阿勒泰地区冬季低温日数气候特征

利用1961～2012年新疆阿勒泰地区7站1月、2月和12月及冬季日最低气温低于-20℃的日数资料，采用线性回归、经验正交函数分解、Mann—Kendll突变检测、R／S分析等方法，对低温日数的时空变化进行了分析。结果表明：（1）冬季及各月的低温日数具有自东南向西北递减的空间分布特征，且1月出现的低温日数最多，12月出现的最少；（2）冬季低温日数的极值空间分布特征与平均值的一致。其中，年极大值出现的时间集中在1960年代中期至1970年代中期之间，年份差异较大，而年极小值均一致的出现在2006年；（3）各站冬季平均低温日数在近51a内的倾向率为-1．71--4．24d／10a，呈减少趋势，而各月的倾向率（吉木乃站1月除外）同冬季的一致，均为负值，但变化率均小于冬季的；（4）第1特征向量场的分布显示，冬季低温日数在空间上具有较好的一致性，高值区位于阿勒泰市、哈巴河县等高发区，中心值为0．455；（5）西部的哈巴河、吉木乃和布尔津3县及中部的阿勒泰市，均没有发生突变，而南部的福海和东部的富蕴和青河2县均在1980年代有下降趋势的突变发生；（6）各站红季及各月的低温日数的R／S分析的H指数显示，未来的趋势与过去一致，仍呈减少趋势。

Climatic Characteristics of Winter Low - temperature Days in Altay Region of Xinjiang

Based on daily low temperature data which was below -20 ℃ from December to February during 1961 -2012 at 7 meteoro- logical stations in Ahay region of Xinjiang, the spatial - temporal variations of low temperature days were analyzed by using linear re- gression, empirical orthogonal function, Mann -Kendall mutation detection and R./S analysis. The result is as follows ：The monthly low temperature days in winter decreased gradually from southeast to northwest with the maximum in January while the minimum in Februar- y. The average winter low temperature days of Qinghe and Fuyun county in the eastern Ahay were the most, which were 75.0 d and 65.9 d,respeetively, while it was the least in Jimunai in the west of Altay, which was only 21.6 d. The spatial distribution of extreme value of winter low temperature days was in accordance with the average value, but the maximum mostly appeared in the middle 1960s to the middle 1970s, while the minimum occurred consistently in 2006. Among them, the maximum and minimum value ranged from 64 d to 86 d and from 0 d to 46 d, respectively. The climatic tendency rate of winter low temperature days at all stations was from - 1.71 to --4.24 d/10 a in recent 51 years, which showed a trend of decrease. Though the monthly tendency rate of all stations was also negative except for Jimunai in January, the value was smaller than that in winter. The first characteristic vector field displayed that win- ter low temperature days existed good consistency on the space with the center of high value 0. 455 in Ahay and Habahe. There was no mutation in Habahe, Jimunal and Buerjin in the west and the central of Ahay, while for Fuhai, Fuyun and Qinghe in the southern and eastern Ahay a mutation with downward trend occurred in the 1980s S analysis was more than 1/2, which meant that the trend of winter that in the past. H index of low temperature days in winter at all stations from R/ low temperature days in future would still decrease compared with