河西走廊东部干旱指数MCI和Pa的时空特征及干旱评估差异研究OA

Comparative analysis was conducted on spatiotemporal characteristics,seasonal drought variations,and classification applicability between MCI and Pa drought indices based on meteorological and disaster records in eastern Hexi Corridor from1961 to 2020.The results showed that:(1)Both annual and seasonal(spring,summer,autumn)drought conditions showed a slow alleviation trend,with MCI exhibiting a higher inter-annual tendency rate than Pa.Spatially,Liangzhou,Minqin and Tianzhu demonstrated consistent trends between the two indices,all showing slow drought alleviation,while Gulang displayed opposite trends(Pa indicated alleviation,whereas MCI suggested intensification).(2)The MCI index indicated higher drought frequency in the southern mountainous regions compared to the central-northern areas,while the Pa index showed the opposite pattern.At the annual scale,both the frequency and intensity of drought identified by MCI were lower than those detected by Pa.However,seasonal analysis revealed that MCI values were lower than Pa in the central-northern regions during spring,summer and autumn,with the reverse pattern observed in the southern areas.(3)Inter-annual drought severity assessments showed that MCI index was slightly lower than the Pa index,with seasonal analyses exposing pronounced spatial heterogeneity in classification disparities.Nevertheless,the indices exhibited remarkable concordance.The two indices exhibited strong positive correlation,with their trend variations well corroborated by historical drought disaster records.This demonstrates their joint applicability for regional drought monitoring and assessment.Their complementary characteristics provide reference for synergistic application of the dual-index system.