Acta Geographica Sinica ›› 2016, Vol. 71 ›› Issue (5): 754-767.

• Climate Change •

### Diurnal variation of summer precipitation and its influencing factors of the Qilian Mountains during 2008-2014

Xuemei LIU(), Mingjun ZHANG(), Shengjie WANG, Jie WANG, Peipei ZHAO, Panpan ZHOU

1. College of Geography and Environmental Science, Northwest Normal University, Lanzhou 730070, China
• Received:2015-11-20 Revised:2016-01-23 Online:2016-05-25 Published:2016-05-25
• Supported by:
National Natural Science Foundation of China, No.41461003;National Basic Research Program of China (973 Program), No.2013CBA01801

Abstract:

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.