Using the Global Navigation Satellite System and Precipitation Data to Establish the Propagation Characteristics of Meteorological and Hydrological Drought in Yunnan, China

Analyzing the spatiotemporal characteristics and evolution of meteorological and hydrological droughts can reproduce the process of drought propagation, which helps reduce the impact of droughts and improve water resources management. While emerging studies have attempted to build drought severity index based on the cutting-edge space geodetic observations, few have focused the propagation characteristics of meteorological to hydrological drought using geodetic data. In this paper, using global navigation satellite systems (GNSS) observations together with precipitation data, we systematically investigated drought propagation in the Yunnan province, Southwest China. We first identified seven meteorological and seven hydrological droughts in Yunnan from January 2011 to May 2021, and the meteorological drought was mainly concentrated in northern Yunnan lasting for 1-11 months. By contrast, hydrological droughts were more severe and larger than meteorological droughts, lasting for 2-16 months. The drought propagation time was 2-7 months, short in the southwest but long in the northeast. Water vapor, precipitation, and water storage demonstrated a spatiotemporal pattern of uneven distribution, with the red river fault (RRF) as the boundary, and their phase difference also presented notable regional differences, indicating that the RRF not only influences spatial variation of water resources but also affects drought propagation. Plain Language Summary The dense global navigation satellite system (GNSS) network has become a powerful tool for monitoring atmospheric water vapor and terrestrial water storage. By analyzing the evolution and spatiotemporal patterns of meteorological and hydrological droughts through the GNSS-based drought monitoring method, we investigated the propagation characteristics from meteorological to hydrological droughts and potential influencing factors. Our results suggest that the Yunnan province in China has experienced serious meteorological and hydrological droughts from January 2011 to May 2021, and hydrological drought was more severe than meteorological drought. The meteorological drought was mainly responsible for the hydrological drought, and the drought propagation time was 2-7 months. Furthermore, the red river fault not only influences the spatial variation of water resources but also affects drought propagation.