Abstract:

Annual distribution of precipitation was concerned with flow recharge situation.Nonuniformity of precipitation was the primary cause of flooddrought disasters in monsoon climate zone.Based on the daily precipitation data of 84 meteorological stations from 1961 to 2005 over the Huaihe river basin，provided by Climate Center of Henan Province and National Meteorological Information Center，China Meteorological Administration，precipitation nonuniformity，including nonuniformity coefficient，concentration degree，concentration period and flooddrought 〖WTBX〗Z〖WTBZ〗index were calculated and analyzed.The results showed that the annual distribution of precipitation in the Huaihe river Valley was distinctly heterogeneous，especially in the north area.Compared with the south of Huaihe river basin,the precipitation of north was not abundant，which aggravated the drought of the north in Huaihe river basin.The nonuniformity distribution of precipitation varied distinctly between years——variation of upstream was more distinct than that of downstream；furthermore，variation tendency of the north was different with that of the south，and the amplitude of variations was also different.The concentration period of precipitation were delayed gradually from south to north，and precipitation concentration period was consistent with the main flood season time.Variation of precipitation 〖JP2〗concentration period in the south was much more obvious than that of the north——the precipitation of south Huaihe river varied visible，while the precipitation of north was smoother.The flooddrought was significantly related to the precipitation concentration degree in the most area of Huaihe river basin.