Abstract:Taking the Naoli River Basin as a typical agricultural watershed in cold regions, a comprehensive drought index integrating multi-source information was constructed to evaluate the drought characteristics of agricultural watersheds in cold regions, and its applicability was analyzed. Based on the constructed SWAT model, the hydrological and meteorological elements of the Naoli River Basin were simulated, and the single standardized precipitation evapotranspiration index (SPEI), standardized soil moisture index (SSI) and standardized runoff index (SRI) were calculated. The principal component analysis method and entropy weight method were used to weight three single drought indexes, and the optimal combination weights were calculated using the minimum deviation method to construct an optimized comprehensive drought index (OCDI) that integrates meteorological drought, agricultural drought, and hydrological drought information. The results show that the monitoring results of drought events by OCDI are highly consistent with historical drought events, and considering multiple time scales, OCDI is more accurate and comprehensive in describing the drought situation in the Naoli River Basin. The spatial distribution differences of drought severity monitored by three single drought indices are significant. OCDI, which integrates multi-source information, can reveal the comprehensive drought characteristics of the Naoli River Basin from multiple perspectives of meteorological drought, agricultural drought, and hydrological drought. OCDI has a high correlation with different types of single drought indexes. In the upstream of the Naoli River Basin, OCDI has better comprehensive characterization ability for drought, and comprehensive characterization ability of the annual scale OCDI is better than the seasonal and monthly scales. OCDI can better identify and distinguish the comprehensive drought degree of the basin. With the increase of the comprehensive drought degree identified by OCDI, the actual drought affected area in the basin increases accordingly.
