Response of Agricultural Drought to Meteorological Drought in Baihe Irrigation Area

The objective is to improve the ability and level of agricultural drought early warning,this paper takes Baihe Irrigation District as the research area. The meteorological drought index SPI（Standardized Precipitation Index）is used and the agricultural drought index SSI（Standardized Storage Index）,the response relationship between the intensity and duration of two types droughts in Baihe irrigation area from 1990 to 2016 is analyzed. The results show that:（1） The duration and intensity of agricultural drought are related not only to the duration and intensity of meteorological drought,but also to the process of crop water use in irrigation area.（2） The duration and intensity of agricultural drought on the time scale of one month have the best response to the duration and intensity of meteorological drought of three months.（3）Compared with five different response relationships,and combined with the response degree of agricultural drought to meteorological drought on a one month time scale,the exponential model is the best response model of one month time scale agricultural drought to three months meteorological drought.The relationship between drought intensity and diachronic response are:y = 2.211 5 e^0.1017x、y = 2.790 5 e^0.0782x.