利用2012-2019年乌鲁木齐市6个国家级气象站夏季逐时降水资料,分析全市和不同区域近8 a逐时降水日变化特征。结果表明：（1） 近8 a乌鲁木齐市夏季不同量级降水量和降水日数空间分布总体是由山区向郊区减小,一般性降水对总降水贡献最大。（2） 全市和各区域逐时累计降水量和降水频次变化趋势较显著,增加速率明显大于下降速率,山区明显高于城区和郊区。（3） 全市与山区降水量峰值均出现在16:00-00:00,城区在00:00-04:00,郊区在02:00-07:00;降水频次峰值出现时间有一定差异,最易发生降水的时段大都在夜间;降水强度日变化与降水量和降水频次存在一定差异,山区最大值出现在17:00,城区在20:00,郊区在16:00。（4） 全市和各区域降水主要以短历时降水为主,持续1 h降水次数出现最多,对总降水频次贡献最大;全市和山区持续2 h降水量最多,城区持续3 h和郊区持续6 h的降水量最多;全市持续1~6 h的降水量占总降水量的60.7%,且以夜雨、短历时降水为主。

Based on summer hourly precipitation data from six meteorological stations in Urumqi City, Xinjiang, China between 2012 and 2019, we analyzed the daily characteristics of hourly precipitation over the last eight years. The results show that: (1) Over the past eight years, the spatial distribution of summer precipitation and days of precipitation in Urumqi generally has declined from mountainous areas to the suburbs. General precipitation highly contributes to the total precipitation. (2) The trend of hourly cumulative precipitation and precipitation frequency in the entire city and each region was remarkable. The rate of increase was significantly higher than the rate of decrease, and the rate of increase in mountainous areas were substantially higher than that in urban areas and suburbs. (3) The peak values of precipitation in the entire city and mountainous areas were appeared from 16:00 to 00:00, from 00:00 to 04:00 in urban areas, and from 02:00 to 07:00 in the suburbs. There were some differences in the peak hours of precipitation frequency, with the heaviest periods of precipitation being night-time. Daily variations in precipitation intensity differed from precipitation and precipitation frequency. The maximum value appeared at 17:00 in mountainous areas, 20:00 in urban areas, and 16:00 in the suburbs. (4) Short-duration precipitation was the main precipitation in the entire city and each region. The frequency of precipitation lasting one hour was the highest, highly contributing to the total frequency of precipitation. Precipitation throughout the city and in mountainous areas lasted for two hours but was the highest. Precipitation lasted three hours in urban areas and six hours in the suburbs that were the highest. Precipitation that lasted for one to six hours represented 60.7% of the total precipitation in the entire city and consisted mainly of night-time and short-term precipitation.