Quantile delta-mapped spatial disaggregation analysis for climate variations over the Yangtze River Basin

Abstract

Abstract Significant increases in temperature and precipitation due to global warming affect socio-economics. Accurate analysis is needed for future temperature and precipitation changes in the Yangtze River Basin (YRB). A novel quantile delta-mapped spatial disaggregation (QDMSD) approach was developed in this study to analyze temperature and precipitation changes for the first time over the YRB. The evaluation results show that while QDMSD has a similar performance in simulating temperature with the bias correction and spatial disaggregation (BCSD) model, it shows improvement in reproducing precipitation. Projections indicate the annual mean temperature will increase from 2020 to 2080 under SSP2-4.5 and SSP5-8.5. The projected temperature obtained from five downscaled GCMs has the smallest ranges of differences in summer. Conversely, under SSP2-4.5, annual mean temperatures significantly decrease from 2081 to 2100. In terms of spatial distribution characteristics, most of the positive changes tend to expand across the YRB. The annual mean precipitation will increase from 2020 to 2080 but decreases from 2081 to 2100 under SSP2-4.5 over the YRB. In terms of spatial distribution, precipitation in the southeast region of the YRB will increase, and the maximum variations in precipitation will occur downstream of the YRB. The QDMSD method reproduces observed precipitation trends well and enhances simulation accuracy in the YRB. For projected temperature, there will be a widespread increase across the YRB; for projected precipitation, significant increases will occur in the eastern YRB. These findings support policy-making to address potential risks from temperature and precipitation changes across multiple sectors (e.g., agriculture and industry).