Characteristics of spatial and temporal distribution of temperature and precipitation in the Weihe River Basin under CMIP6 models

The Weihe River Basin is one of China's significant grain-producing areas, and researching future climatic conditions of the basin will provide strong support for achieving the overall objective of “ecological protection and high-quality development of the Yellow River Basin.” Utilizing data from 27 meteorological stations within the Weihe River Basin (1979—2014) in conjunction with NCEP reanalysis data, a downscaled model using SDSM was constructed. This model was applied to three different scenarios of a CMIP6 multi-model ensemble (SSP1-2.6, SSP2-4.5, and SSP5-8.5) to predict future temperature and precipitation changes in the basin. Simulation results indicate that the SDSM model performs excellently in the simulation of temperatures within the Weihe River Basin but slightly less so in precipitation simulation; future temperatures in the Weihe River Basin are expected to continue to rise, with a spatial distribution trend decreasing from south to north; future precipitation in the Weihe River Basin is expected to increase, with a spatial distribution showing higher levels in the southeast and lower in the northwest; the magnitude of trends in both temperature increase and precipitation increase follow the order SSP5-8.5 > SSP2-4.5 > SSP1-2.6. Future temperatures in the Weihe River Basin are expected to exhibit alternations between “cold” and “warm” phases, whereas future precipitation levels will alternate between “abundant” and “scarce” phases.