Abstract:

The precipitation is the main factor of the flood,thus the characteristics of areal precipitation plays an important role in the flood risk mitigation for a river basin.The method of anomaly analysis,MannKendall test and Rescaled Range Analysis were applied to detect the changing characteristics and the future trend of the areal rainfall in the Hongze Lake catchment.Results show that the areal rainfall fluctuated greatly and underwent an insignificant upward trend in the recent 58 years since 1951.The areal rainfall in the Hongze Lake catchment decreased from 1950s to 1970s firstly, and then increased from 1980s to the present which could be a regional response to the global warming.Climatic jump occurred in 1956 and 2003 which resulted in a big catchments wide flood,indicating that the anomalies of the rainfall might be responsible for the flood in the Hongze Lake catchment. Furthermore,Hurst index of Rescaled Range Analysis is 0.538,which implies that the future tendency will maintain its current upward trend and it may have a random increasing trend demonstrating the uncertainty of the future precipitation.The understanding of the characteristics of precipitation and its future trend may be of great importance for the flood risk reduction in the Hongze Lake catchment.