利用1991—2014年新疆16个国家基准气象站逐时降水资料，分析了新疆夏季不同区域降水日变化基本特征，揭示出新疆夏季降水日变化呈现显著的南、北疆区域差异，有别于我国中东部的一些新事实。结果显示：北疆降水量日变化呈现准单峰型特征，峰值主要发生在傍晚前后（16：00—20：00，地方时，下同）；南疆降水量日变化呈现三峰特征，峰值分别出现在傍晚（17：00—18：00）、午夜后（00：00—01：00）和上午（10：00）。新疆夏季降水事件以6 h 以内的短历时性质为主（平均为85％，比例明显高于我国中东部），而持续12 h 以上的较长历时降水事件偶有发生；在天山东麓以外的新疆绝大部分地区，6 h 以内短历时降水事件对总降水量的贡献率达54％，高于我国中东部地区。新疆西部和北疆北部降水量日变化主峰的贡献者是2～3 h 短持续性降水为主的事件；而天山中—东部降水量日变化峰值则是来自于12 h 内各不同持续时间降水事件的大致均等贡献。
Diurnal Variations of Summer Precipitation in Xinjiang
Fundamental diurnal variation features of summer precipitation over Xinjiang are investigated based on hourly precipitation data of 1991-2014 from all 16 national stations in the target region,and distinct char-acteristics on the diversity of diurnal variations of summer precipitation between Northern and Southern Xinjiang are revealed.Results show that the diurnal variation of the precipitation amount in Northern Xin-jiang presents nearly a single peak and trough,with the maximum at dusk (1600 -2000 LST)and mini-mum about one-third proportion of peak value at noon time,and the precipitation amount almost decrease monotonically during the whole night.Differently,the diurnal variation of the precipitation amount in Southern Xinjiang shows triple peaks and troughs,with peaks at about dusk(1700-1800 LST),after the midnight (0000-0100 LST)and near the noon (1000 LST),respectively.The difference of single peak pattern between Northern Xinjiang and central-east China is the accumulation of different situations instead of similar peak overlay.In addition,the morning when precipitation peak value appears in Southern Xin-jiang is opposite to that weaker or weakest time in all day in central-east China. The occurrence time of maximum average precipitation intensity and maximum hourly accumulative precipitation is more consistent with the counterpart of maximum hourly accumulative precipitation fre-quency,and more remarkable with the region where daily variation of precipitation presents multi-peak patterns,showing more contribution of precipitation intensity than frequency to accumulative precipitati-on,which is also an important characteristic of Xinjiang,especially in Southern Xinjiang.Short-duration precipitation within 6 hours are dominated events in summer (the average value is 85 percent which is sig-nificantly higher than that in central-east China),and precipitation events lasting longer than 12 hours happen rarely.Contribution rates of short-duration precipitation events within 6 hours in total precipitation are up to 54% which is higher than that in central-east China in most region except the east side of Tians-han in Xinjiang. Except in the south edge of Tarim Basin,there are close relations between the precipitation diurnal cy-cle and its duration in most areas of Xinjiang,but not the same as those in central-east China.Namely,2-3-hour short-duration precipitation events contribute to the peak value of the total precipitation diurnal cycle in western and Northern Xinjiang,whereas every duration event within 12 hours has nearly equal contribution to the maximum of the total precipitation diurnal cycle in central to eastern Tianshan Mountains.
NETL
NSTL
万方数据
维普
