沅江流域气象-水文干旱时空演变及传播特征OA

[Objective]This study aims to analyze the propagation time and patterns from meteorological drought to hydrological drought,providing theoretical guidance for regional drought early warning and prevention.[Methods]The Yuanjiang sub-basin in the Dongting Lake Basin was taken as the research object.The drought indices,including standardized precipitation index(SPI),standardized precipitation evapotranspiration index(SPEI),and standardized runoff index(SRI),were applied in combination with the theory of runs and Pearson correlation analysis to examine the spatiotemporal characteristics and propaga-tion processes of meteorological and hydrological droughts.[Results](1)In terms of frequency,hydrological drought occurred at a level comparable to meteorological drought,whereas the mean duration and severity of hydrological drought were stronger than those of meteorological drought.(2)Spatially,drought frequency based on SPI-3 showed a decreasing trend from northwest to southeast,while that based on SPEI-3 showed the opposite trend.Temporally,SPI-and SPEI-based meteorological droughts had similar characteristics,both exhibiting the same future trends with hydrological drought(SRI),characterized by increasing dryness in spring and autumn and gradual wetness in summer and winter.However,hydrological drought lagged behind meteoro-logical drought,requiring a propagation time.(3)The propagation process from meteorological drought to hydrological drought exhibited obvious seasonal differences.The propagation time was shorter and the correlation was higher in spring and summer,while the propagation time was longer and the correlation was lower in autumn and winter.Overall,the drought propagation time ranged from 1 to 5 months.[Conclusion]The duration and intensity of hydrological drought are stronger than those of meteoro-logical drought,and their frequencies are relatively equivalent.The spatial distribution of drought varies with indices,whereas the temporal trends are consistent.Hydrological drought lags behind meteorological drought.The meteorological-to-hydrological drought propagation time and its correlation show seasonal differences.