The Impact of Climatic Conditions, Human Activities, and Catchment Characteristics on the Propagation From Meteorological to Agricultural and Hydrological Droughts in China

Droughts are one of the most frequent and destructive natural disasters worldwide. In the past decades, drought events in China are frequent and caused severe socio-economic losses. To better predict and manage droughts, the spatiotemporal characteristics of the three types of droughts and propagation time (PT) from meteorological to agricultural and hydrological droughts in China during 1982-2014 were analyzed based on drought indices, while the causes of drought propagation were discussed. The results showed that meteorological droughts exhibited an insignificant trend. Agricultural droughts mainly aggravated in the northeastern and central regions. And the hydrological droughts were long-lasting and exacerbated in most areas. The propagation speed from meteorological to agricultural and hydrological droughts was extremely rapid (1-2 months) in southeast China, and the relationships among droughts were close (correlation coefficient/R > 0.6). The propagation from meteorological to hydrological droughts was slower (6-8 months) in central China. In northwest China, the association between meteorological and hydrological droughts was weak (R < 0.4). Climatic conditions (especially temperature) played a dominant role in the propagation from meteorological to agricultural and hydrological droughts, explaining 63.3% and 52.6% of the variations in the PT, respectively. Urbanization, agricultural activities, elevation, and vegetation contributed to the propagation from meteorological to agricultural droughts. Reservoirs, agricultural activities, and vegetation also affected the propagation from meteorological to hydrological droughts by regulating hydrological processes. These findings are of vital significance to the prediction, warning, and management of different droughts.