中文摘要：

基于中国自动气象站与CMORPH降水产品融合的逐时降水量0.1°×0.1°网格数据集通过逐时降水量、降水频率和降水强度等指标研究了2008-2014年祁连山区夏季降水的日变化特征,并结合ERA-Interim再分析资料分析了气象要素对降水日变化的影响。结果表明：1祁连山区逐时平均降水量和降水频率的时空分布特征较为一致,即东中段大于西段,且7月最大,6月次之,8月最小;降水强度的空间分布则与降水量和降水频率的存在差异,且6月的降水强度平均值最大。2白天和夜间的降水量均表现出东中段多于西段、山区多于平原的特点,并有明显的夜雨现象;从年际差异来看,2008-2014年白天和夜间的降水量均呈增加趋势。3祁连山区夏季降水平均相对变率介于5%~38%之间,全区20：00平均相对变率最大;逐时降水量和降水频率普遍存在较好的相关性,尤其是在东中段。4对比再分析资料发现,祁连山区降水日变化与相对湿度和地面温度等气象要素有关。

英文摘要：

To investigate the diurnal characteristics of precipitation in the Qilian Mountains during the summer of 2008-2014, the hourly mean precipitation, frequency and intensity were calculated using an hourly merged precipitation dataset derived from the national automatic weather stations and CMORPH（Climate Precipitation Center Morphing） product at a 0.1°×0.1°resolution. In addition, the relative humidity and air temperature from ERA-Interim（European Reanalysis Interim） reanalysis database was also used to analyze the influence of meteorological variables on diurnal precipitation variation. The main results are as follows：（1）The spatial distribution and temporal variation of mean hourly precipitation and frequency are generally similar, and hourly precipitation in the eastern and central parts is larger and more frequent than that in the western part. On a monthly basis, the maximum values of precipitation and frequency usually occurred in July, while the minimum values usually occurred in August.The spatial distribution of precipitation intensity was different from that of amount and frequency, and the maximum was observed in June.（2） The increasing trends from west to east were detected for precipitation in both daytime and nighttime. The mountains usually had more precipitation in both daytime and nighttime, and the night rain was frequent for the study region. During 2008- 2014, the precipitation in both daytime and nighttime increased.（3） The average relative change rate of precipitation was between 5%-38% with maximum value at 20：00（Beijing Time）. The hourly precipitation was significantly correlated with frequency,especially for the middle and eastern parts.（4） The reanalysis of data indicated that the diurnal variation of precipitation in the Qilian Mountains is related with other meteorological variables,such as relative humidity and air temperature.