Spatiotemporal variations of meteorological drought and its dominant factors in different climate regions for the first two decades of the twenty-first century

Drought events have become increasingly frequent and intensive due to the combined influence of climate change and anthropogenic activities. However, it remains unclear how meteorological drought characteristics (duration, severity, and intensity) respond to the changing environment and what are the dominant factors determining the drought evolution in different climate regions. Here, we divide mainland China into four sub-climatic regions, namely the Humid region (HR), Transition region (TR), Arid region (AR), and Tibetan Plateau (TP), based on the aridity index and geomorphology. Then systematically investigate the spatiotemporal patterns of drought characteristics in different climate regions over China (during 2000-2019) based on the SPEI and run theory. And the contribution of precipitation (Pre) and potential evapotranspiration (PET) to drought characteristics are quantitatively analyzed using a detrended numerical experiment method. We find that (1) a pattern of "dry gets drier, wet gets wetter" was found in China. (2) Meteorological drought characteristics exhibit apparent regional heterogeneity: droughts in AR are of long duration and high severity, while droughts in HR and TR show a pattern of high frequency. (3) An increase in the annual Pre (PET) resulted in increases (decreases) in average SPEI in China of 45.18% (31.62%). Therefore, Pre is the dominant factor determining the increase of SPEI over China. For the four sub-climatic regions, Pre is the dominant factor in the increase of SPEI in TR and HR, with the contribution of 41.64% and 60.16%. PET is the dominant factor in the decrease of SPEI in AR, with the contribution of 50.11%. The contributions of Pre (45.09%) and PET (44.09%) in TP are roughly equivalent. These findings provide valuable insights for policymakers in shaping climate change adaptation and mitigation strategies. By understanding the leading meteorological factors influencing drought, policymakers can implement effective measures to minimize the influence of disasters.