An Analysis of Droughts in China Since the 21st Century Based on Soil Moisture Remote Sensing Products

Agricultural drought in China since the 21st century is an important but little discussed issue. In this study, we adopted NNsm, a newly developed long time series soil moisture product based on remote sensing and artificial neural networks, to identify the drought events in China from 2002 to 2019 by using the severity-area-duration (SAD) analysis. The results show there were 52 long-term drought events (
$\geq 4$
months) in the study period, while 83.81% of the areas in China have experienced drought. In 2015, the drought area was the largest. There was a drying trend in southern China, central Xinjiang and central Tibet, while a wetting trend in eastern Xinjiang and eastern Tibet. This study suggests the drought develop trend and reveals the areas vulnerable to drought in China, which can help with drought monitoring and mitigation, as well as scientific and technological support for early warning of agricultural drought.