Analysis on spatiotemporal evolution and meteorological driving factors of future meteorological drought in Northwest China based on CMIP6

Abstract

Study region

Northwest China

Study focus

In arid and semi-arid regions, the future evolution and drivers of meteorological drought have received extensive attention. This study focuses on projecting the future annual and seasonal spatiotemporal changes of meteorological drought in Northwest China under the SSP1–2.6, SSP2–4.5, SSP3–7.0, and SSP5–8.5 scenarios by calculating the drought indices SPEI12, SPEI03 and applying the run theory based on the output data of 21 GCMs associated with the Coupled Model Intercomparison Project 6 (CMIP6) and the data from 152 meteorological stations. We further focused on Spearman correlation coefficient and convergent cross mapping (CCM) to identify the relationship between meteorological elements and SPEI (Standardized Precipitation Evapotranspiration Index), and used multiple linear regression to quantitatively analyze the contribution of drivers to SPEI changes.

New hydrological insights for the region

The temperature, precipitation, evapotranspiration, and solar radiation in Northwest China exhibit a significant increasing trend, whereas relative humidity and wind speed show a decreasing trend. Future meteorological drought conditions are projected to intensify compared to the historical period, with seasonal variations showing alleviation in autumn but intensification in winter. Spatially, more severe meteorological drought conditions are observed in southern Xinjiang and the Hexi Corridor. As the emission scenarios become more severe, drought indicators including frequency, duration, peak intensity, and severity show increasing trends. The drought areas are primarily attributed to the increase of moderate and severe drought areas. Individual meteorological elements exhibit a strong correlation with SPEI, with temperature and precipitation being the dominant factors influencing SPEI changes. However, the contribution of solar radiation during spring and winter seasons should not be overlooked. This study establishes a scientific foundation for drought risk assessment and provides a reference for the formulation of water resource management strategies.