Temporal and spatial response of agricultural drought to meteorological drought in inner Mongolia plateau inland river basin.

Meteorological drought is the primary cause of agricultural drought. Studying how agricultural drought responds to meteorological drought is crucial for understanding drought evolution. This paper takes the inland river basin of the Inner Mongolia Plateau as the research object, characterizes meteorological drought and agricultural drought respectively by the standardized precipitation evapotranspiration Index (SPEI) and the standardized Soil Water Index (SSMI), analyzes the spatio-temporal continuous dynamic evolution characteristics of drought in the study area from 1961 to 2021, explores the spatio-temporal response characteristics of meteorological and agricultural drought, and establishes a drought characteristic response model. The results show that: (1) The three dimensional (3D) identification method can accurately and comprehensively understand the dynamic evolution process of drought events and regional drought development law; (2) A total of 28 drought event pairs were successfully matched from 1961 to 2021, and the matching results can ensure that the complex relationship between the two types of droughts on the temporal and spatial scale is closer to reality; (3) The optimal response models for duration, area and severity of drought in the study area are Gaussian Copula function, Clayton Copula function and Clayton Copula function, respectively. This study provides a new method for accurately assessing the spatio-temporal variation and response of drought.