Abstract:  Based on the hourly precipitation data of 10 national meteorological stations from 2012 to 2019, the diurnal variation characteristics of precipitation in different seasons in the Yili River Valley of Xinjiang were analyzed. The results are as follows: (1) The diurnal variation characteristics of cumulative hourly precipitation in the Yili River Valley showed a single peak in spring, summer and winter, and a double peak in autumn. The low value period of diurnal accumulated hourly precipitation in four seasons appeared in the afternoon (15:00-19:00), the high value period appeared in the morning (10:00-12:00) in spring, autumn and winter, and in the first half of the night in summer (22:00). (2) The diurnal variation characteristics of cumulative precipitation frequency and cumulative precipitation in the same season were similar. There were significant regional differences in spatial distribution of hourly average precipitation and peak precipitation frequency. (3) Shortduration precipitation events were the main events in four seasons in the Yili River Valley, with the highest proportion (89%) in summer and the lowest proportion (70%) in winter. Short duration precipitation events were the main contributors to total precipitation in summer, while long duration precipitation events were the main contributors to total precipitation in winter. (4) There was a close relationship between the daily circulation of precipitation and the persistence of precipitation in four seasons in the Yili River Valley. The precipitation events lasting for 2-8 hours and 1-4 hours were the main contributors to the diurnal variation of precipitation in spring and summer. Three types of precipitation events with different durations had roughly equal contributions to the diurnal variation peaks of precipitation in autumn and winter in the Yili River Valley.

Key words:  hourly precipitation, diurnal variations, seasonal variation, Yili River Valley

摘要： 利用2012—2019年新疆伊犁河谷10个气象站逐小时降水资料，分析该区域不同季节降水的日变化特征。结果表明：（1）伊犁河谷春季、夏季和冬季的累计降水量日变化呈单峰型，秋季呈双峰型。四季累计降水量日变化的低值都出现在下午（15：00—19：00），高值时段在春季、秋季和冬季的上午（10：00—12：00），夏季高值出现在前半夜（22：00）。（2）同一季节累计降水频次和累计降水量的日变化特征类似，逐时平均降水量和降水频次峰值的空间分布均存在明显区域差异。（3）伊犁河谷四季均以短历时降水事件为主，该类事件在夏季出现比例最高（89%），冬季出现比例最低（70%），且短历时降水事件是夏季总降水量的主要贡献者，而长持续性降水事件是冬季总降水量的主要贡献者。（4）伊犁河谷四季降水的日循环与降水的持续性之间都存在密切关系，其中持续2～8 h和1～4 h的降水事件是春季和夏季降水量日变化峰值的主要贡献者，不同持续时间降水事件对秋季和冬季降水量日变化峰值的贡献大致相等。

关键词: 小时降水, 日变化, 季节变化, 伊犁河谷