Spatial Trend of Summer Precipitation and its Implications for Flood Risks in the Huaihe River Basin, China

摘要

Trend detection of hydrological variables isimportant in the understanding of flood risks in a river basin.Nonparametric technique was applied to the analysis of summerprecipitation in Huaihe River Basin (HRB). Results shows thatmean precipitation varies greatly with greater values occurringin July temporally, and that greater values occur in the southernand eastern HRB and smaller values in the western and northernHRB spatially. In June, four stations, Xuzhou, Bengbu, Baofengand Xuchang, which are in the upper to the middle reaches of theHRB, exhibit a statistically significant increasing trend; twostations show significant decreasing trend and one stationincreasing trend in July, they are Juxian, Rizhao and Kaifengrespectively, these three stations are mostly in the northern HRB;no significant trend is detected in August. Xihua and Rizhao havestatistically significant increasing trend and decreasing trend insummer precipitation respectively. The Hurst H values indicatethat there could be a slight decreasing trend in Gaoyou, Xuyi,Bengbu and Shangqiu in summer precipitation. For the reststations, the future tendency of summer precipitation would beconsistent with those of the past years. A long-range dependencecharacteristic exists in precipitation means that summerprecipitation will maintain a detected significant decreasingtrend in Rizhao and increasing trend in Xihua in the near future.Considering the trend of summer precipitation, it can notconclusively say that the flood risks are predominantly caused byclimate change in the HRB, for the precipitation demonstrates nosignificant increasing trend in the HRB. Therefore, a moredetailed research on the climate change and human activities isneeded to obtain a wider understanding of the flood risks.