Abstract:

Using daily precipitation data at 21 weather stations in Hebei province from 1958 to 2012, climatic characteristics, annual and inter-decadal variations of heavy rain events and their trends during flood seasons were analyzed. The results indicate that heavy rain events during flood season are higher in the east and south than in the northwest. The largest center of heavy rain is located in the east of Hebei province, Tangshan and Qinhuangdao regions. According to the analysis of the inter-annual and inter-decadal scale, rainfall, frequency and intensity of heavy rain have a 2-3-year cycle, and the first two have a 15-20-year cycle after 1980s. Rainfall and frequency of heavy rain during flood season are in a declining trend, especially after 21st century. However, change of heavy rain intensity is not significant. For spatial distribution of heavy rain, inter-decadal rainfall and frequency as well as intensity all decrease to east and to south, and three indexes are in a declining trend in the most weather stations.

Key words: Flood season, Heavy Rain, Cycle, Morlet analysis