Abstract: Based on the hourly precipitation data at 24 meteorological stations of Shandong Peninsula from May to October during 1985-2016 and 6-hour reanalysis data of ECMWF from May to October during 2010-2016, the diurnal variation characteristics of precipitation in summer half year were analyzed in detail. The results are as follows: (1) The diurnal distributions of precipitation, precipitation frequency and precipitation intensity appeared double peaks pattern in Shandong Peninsula in summer half year, and the peaks appeared from 02:00 BST to 05:00 BST and at about 15:00 BST, respectively. The peak of precipitation and precipitation frequency in early morning was obviously greater than that in the afternoon. (2) The contribution of long-duration precipitation to total precipitation was greater than that of short-duration precipitation in summer half year in Shandong Peninsula. The peak of the former occurred from 03:00 BST to 06:00 BST, while the main peak of the latter occurred from 15:00 BST to 18:00 BST, which indicated that they had dominant impacts on the peak of total precipitation in early morning and afternoon, respectively. (3) The contribution of light rain to total precipitation frequency was the maximum at any time during a day, and the frequency of light rain accounted for nearly half of total precipitation frequency. However, the precipitation intensity of heavy rain and torrential rain was significantly stronger than that of light rain and moderate rain, they had greater contribution to total precipitation, so the total precipitation was mainly due to heavy rain and torrential rain.

Key words: precipitation, diurnal variation, duration, precipitation grades, Shandong Peninsula

摘要： 利用1985—2016年5—10月山东半岛地区24个气象观测站逐小时降水资料和2010—2016年5—10月ECMWF逐6 h再分析资料，详细分析了山东半岛夏半年降水的日变化特征。结果表明：（1）山东半岛地区夏半年降水量、降水频率和降水强度的日变化均呈双峰型特征，峰值出现在02:00—05:00和15:00前后，其中降水量和降水频率清晨峰值明显高于下午；（2）长持续性降水对总降水量的贡献大于短持续性降水，前者的日峰值出现在清晨03:00—06:00，后者的主峰出现在15:00—18:00，分别主导总降水量清晨和下午的峰值；（3）小雨对降水总频率的贡献最大，几乎占总频率的一半，而大雨和暴雨对总降水量的贡献更大，故而总降水量主要来自于大雨和暴雨。

关键词: 降水, 日变化, 持续时间, 降水等级, 山东半岛