太原市夏季降水的日变化特征

Diurnal variation characteristics of summer precipitation in Taiyuan

利用太原市所属3个国家一般气象站1991-2013年逐时自记降水资料，分别代表太原市山区、市区、平川，分析了太原市夏季（6-8月）降水日变化的基本气候特征及其长期演变趋势。分析结果表明，太原市不同区域夏季降水日变化在降水量和降水频次上表现出较为一致的变化特征，均以午后至次日凌晨为高值区，而在中午前后为低值区；高值区可进一步划分为2个峰值区间，一个峰值位于午后至傍晚，另一个峰值发生在凌晨。结合每次降水的持续时间对日变化的气候特征进行分析，可以对降水量的2个峰值进行区分。下午至前半夜的降水主要表现为持续时间少于4h的降水事件，而后半夜至清晨的降水峰值则主要由持续时间犬于4h的降水事件累积而成。2010年以后，短持续性降水的降水总量有所减少，而长持续性降水事件的降水总量有所增加。

Using 3 national meteorological station precipitation observations from 1991 to 2013, the basic climatic characteristics of diurnal variation and long term evolution trend of diurnal variation characteristics ot summer precipitation in Taiyuan have been discussed. The results indicated that the precipitation and its frequency ot different areas of Taiyuan showed consistent, which were high in the afternoon to the early morning, while in the low value around noon. High value region could been further divided into 2 peaks, one in the afternoon to the late afternoon, and the other in the early morning. After 2010, the total precipitation of short duration precipitation decreased, but the total precipitation of continuous precipition increased.