2010—2016年新疆阿勒泰地区暖季降水日变化特征

Characteristics of Diurnal Variation of Precipitation in Warm Season in Altay of Xinjiang During 2010-2016

利用阿勒泰地区2010—2016年5—9月(暖季)21个自动站逐时降水资料,运用常规统计法,采用逐时降水量及其频次和强度、不同持续时间降水4个指标对该区暖季降水日变化特征进行研究。结果表明,阿勒泰地区暖季降水总量及日数的空间分布总体上与海拔、纬度呈正相关,与一般规律不同。该区逐时降水量及其强度日变化山区呈双峰型,峰值出现在17:00—18:00和22:00(北京时,下同),其他区域及全地区呈单峰型,峰值出现在16:00—19:00。一般性降水量及其频次、逐时降水频次山麓丘陵区呈双峰型,其他区域为单峰型。强降水量主要发生在午后至旁晚。该区降水主要以短历时为主,持续1 h的次数最多,持续2 h的降水量最多,对总降水量的贡献也最大;持续1~3 h的降水次数占总降水次数的84.1%,与我国东部地区不同。在月分布上,8、9月与暖季差异较大。该区暖季降水主要是昼雨,且以短历时降水为主,与伊犁河谷和南疆不同。

Based on the hourly precipitation data from 21 automatic meteorological stations in warm season（ from May to September） in Altay region of Xinjiang from 2010 to 2016,the diurnal variation characteristics of precipitation in warm season were analyzed by using four precipitation indexes including hourly precipitation,hourly precipitation frequency,hourly precipitation intensity,and different duration precipitation. The results show that the spatial distribution of total precipitation and rainfall days in warm season of Altay presented positive correlation with elevation and latitude as a whole,it was different from the general law. The diurnal variation of hourly precipitation and its intensity in mountainous region showed a double peaks,and the maximum appeared during 17：00-18：00 and at22：00,while in other regions it presented one peak and the maximum appeared during 16：00-19：00. General precipitation and its frequency,cumulative hourly precipitation frequency presented a double peaks in foothills,and in other regions they showed one peak.Heavy precipitation and its frequency mainly concentrated from afternoon to evening. There was mainly short-term precipitation,rainfall lasting for one hours occurred most,and rainfall lasting for two hours contributed the maximum precipitation amount to the total precipitation,the times of rainfall lasting for one to three hours was about 84. 1% of total rainfall,which was different from eastern China.Rainfall in August and September was different from that in the warm season. Precipitation mainly occurred in daytime,which was different with the Yili River Valley and southern Xinjiang.