Drought frequency characteristics of China, 1981-2019, based on the vegetation health index

Droughts—major natural disasters with a complex development and evolution process—cause enormous losses for society, especially in the agriculture sector. We analyzed the spatiotemporal evolution of drought frequency in China at grid level during 1981-2019 with the nonparametric Mann-Kendall trend method, using a high temporal resolution vegetation health index dataset at week-scale. Results suggest the that (1) after entering the 21st century, China’s drought-affected area has declined, with Northeast China being the least affected region and Northwest China being the most severely affected; (2) the spatial pattern of drought characteristics in China is polarized, and the frequency of droughts has generally declined, with the most prominent intensity and frequency observed in some urbanized and economically developed regions; and (3) although the changes to the drought characteristics and frequency in China provide a generally optimistic picture, drought intensity and frequency in some developed regions have increased significantly, and the future trend predictions for these areas are less positive. This study, focusing on the spatiotemporal characteristics and evolution of drought patterns, with the aim of raising awareness of drought disasters, can help mitigate and prevent the damage caused by droughts to society, and can provide a scientific basis for drought early-warning systems and risk management in China going forward.