Spatio-Temporal Evolution and Propagation of Meteoro-Hydrological Drought in Yalong River Basin

Based on the meteorological and hydrological data of Yalong River Basin from 1960 to 2019, droughts were analyzed using standardized precipitation evapotranspiration index (SPEI) runoff (SRI); then, spatio-temporal evolution propagation characteristics studied multiple time scales. The results showed that, firstly, annual scale, frequencies in basin 28.3% 34.0%, respectively, past 60 years. From upstream downstream, longer alternating period dry wet periods, more significant frequency droughts. Secondly, a seasonal is high autumn, drought autumn winter. different seasons decreases upper reaches lower basin. Thirdly, monthly severe exceptional are March May, January, March, October, December. much higher than that droughts, especially with respect drought. Meteorological spread same without lag, but they tend expand. short summer long spring conclusions can serve as decision-making basis for water diversion planning west route China’s South-to-North Water Diversion Project cascade hydropower operation