Dynamic variation of meteorological drought and its relationships with agricultural drought across China

Abstract

Under the background of climate warming, the global water cycle is gradually accelerating, which will lead to increased drought frequency and severity. China is one of the countries with the highest drought risk and the most serious drought impact, accompanied by abnormal and variable drought characteristics in recent decades. However, the dynamic variation of meteorological drought and its complicated relationships with agricultural drought are still unclear across China. In this study, the characteristics of meteorological drought were comprehensively identified across China during 1960–2019. The spatio-temporal variations and gridded trend characteristics of meteorological drought were revealed during the study period. Subsequently, the return period of meteorological drought was quantitatively determined based on copula models. Finally, the relationships between meteorological and agricultural drought were explicitly clarified. The results indicated that: (1) meteorological drought showed an increasing trend across China from 1960 to 2019, especially since the 1990s; (2) the most serious meteorological drought occurred in 2011, with a minimum standardized precipitation evapotranspiration index (SPEI) value of –0.81; (3) the percentage of drought area (PDA) with an increasing trend in spring, summer, autumn and winter was 85.8%, 77.4%, 97.7% and 12.9%, respectively; (4) the most appropriate copula model of meteorological drought severity and duration was Frank copula; and (5) the propagation time from meteorological to agricultural drought was longer in winter and shorter in summer, which can determine the appropriate irrigation period and predict the occurrence of agricultural drought. This study sheds new viewpoints into the identification of meteorological drought variation and its relationships with agricultural drought, which can also be applied in other areas.