Spatiotemporal characteristics of meteorological to hydrological drought propagation under natural conditions in China

Abstract

Understanding the time required for meteorological drought to propagate to hydrological drought is crucial for producing early warnings of future hydrological droughts. However, most previous studies of this topic have used observed runoff (or streamflow), which usually has been disturbed by human activities, and accordingly, the calculated drought propagation time (DPT) cannot accurately characterize the real propagation characteristics under natural conditions. In this study, we quantified the meteorological to hydrological DPT during the period 1962–2018 based on natural runoff and streamflow datasets and then analyzed the primary meteorological factors in influencing the spatial distribution of DPT. The results show the following: (1) The overall average DPT in China is about 6 months, decreasing from the northwest (9–12 months) to the southeast (1–2 months), and the DPT in spring and winter is generally longer than in summer and autumn. (2) The most sensitive areas for drought propagation during the period 1991–2018 increased in extent by 1.73% when compared with the extent during the period 1962–1990, and river-flow routing processes led to longer DPTs in southeast China and shorter DPTs in northwest China. (3) Precipitation and maximum temperature are the dominant meteorological factors influencing the spatial variability of DPT across China, while river-flow routing changes one of these dominant factors from maximum temperature to mean temperature.

Keywords

• Drought propagation
• Meteorological drought
• Hydrological drought
• Natural runoff
• China