Based on the Hydrological Model to Build Integrated Drought Index in Luanhe Basin

QU Hai-chen; HU Yan-yang; LIU Xiao-dong

doi:10.3969/j.issn.1004-7328.2015.05.011

Abstract：Soil moisture is an important indicator of watershed judgment of drought,which was measured with a one-sided, and unpredictable,but hydrological model can effectively simulate soil moisture throughout the basin. With Luan River basin above the county hydrological station as a research area,based on soil moisture runoff model to simulate vertical mixing basin, the relative soil moisture drought index is constructed. Through the principal component analysis the relative soil moisture, precipitation anomaly percentage and relative wetting degree are integrated to build a comprehensive drought index in order to make a quantitative assessment of the frequency of the different time scales Watershed(year,month,quarter scale)drought. The results show that:the comprehensive drought index can be used to Luan River drought assessment,and drought events that have occurred have better goodness of fit;1960—1989 in Luan River Basin the maximum frequency of special drought for three months is 18.23 percent ,the highest frequency of continuous drought for five months is 17.26 percent,the frequency of light drought for seven months is 9.24 percent;in Luan River Basin the highest frequency of drought in winter is 37.8 percent , the lower frequency of drought in summer is 22.6 percent,the frequencies of severe drought and average drought in winter are respectively 6.0 percent and 11.3 percent,the maximum frequency of special drought in spring is 3.5 percent,the frequency of light drought in summer is 18.1 percent.The results is important to predict the drought in Luanhe basin.