Spatiotemporal dynamic characteristics and influencing factors of propagation time from meteorological drought to agricultural drought

Abstract

Study region

Yangtze River Basin (YRB), China

Study focus

Understanding the propagation from meteorological to agricultural drought is essential for effective agricultural drought risk management. However, the spatiotemporal dynamics and factors influencing this propagation remain poorly understood. This study characterized meteorological and agricultural droughts using the Standardized Precipitation Index and Improved Soil Moisture Anomaly Percentage Index. A correlation analysis combined with a moving window approach was employed to determine the dynamic drought propagation time. Additionally, the eXtreme Gradient Boosting (XGBoost) algorithm was applied to identify the primary factors associated with these variations.

New hydrological insights

The western YRB experienced the most significant fluctuations in propagation time. The propagation times in spring and winter were more sensitive to changing environments. The dominant factor influencing these variations at the grid scale was mean annual temperature (Tem). The factors influencing the spatial variability of the propagation time vary by region and season. Although the mean annual precipitation (Pre) was the most important factor influencing the spatial variation in propagation time in the YRB, the coupling relationship between soil moisture and precipitation (SM_Pre), along with soil moisture memory, dominated this variation in the middle-lower YRB. Seasonally, Pre was the dominant factor influencing the spatial variation in the propagation time in spring, SM_Pre primarily affected this variation in summer and autumn, and Tem was the dominant factor in winter.