Abstract:
Based on the daily precipitation data of 25 typical meteorological stations in Hebei province from 1965 to 2015 (June to September), the spatial and temporal variation characteristics of the precipitation concentration degree(PCD) and the precipitation concentration period (PCP) are analyzed by wavelet analysis and Mann-Kendall as well as the synthetic analysis method. The analysis results show that: ① The PCD value is between 0.18~0.56, and the PCP value is between 47.26°~194.70°, the maximum precipitation in the flood season is concentrated in early and mid of July; both PCD and PCP exist in the main period of about 35 years and sub cycles about 20 years; in the last 50 years, neither PCD nor PCP has mutation years. ②PCD decreases from southeast to northwest, and the PCP in southern Hebei Province is gradually delayed from the northeast to southwest, the PCP of the northern Hebei Province is gradually delayed from the Chengde region to the east and the west in two directions. ③The spatial distribution of the PCD in the more-water year and the less-water year decreases from the southeast to the northwest, but the high value area of the PCD in the more-water year is more than that of the less-water year; The spatial distribution of the PCP is consistent in the more-water year and the less-water year, the PCP in the southern Hebei Province is gradually postponed from the central region to the north and the south sides, the PCP in the northern Hebei Province is gradually postponed from Fengning and Weichang to the east and the west sides, but compared with the more-water year, the PCP range of the less-water year is longer, and its spatial differences are greater. ④From the relevant analysis, the precipitation in the flood season has a good positive correlation with PCD in the whole province, and only has a good negative correlation with the PCP of Chengde, Shexian, Qinghe and Guantao.