Evaluating NEX-GDDP-CMIP6 performance in complex terrain for forecasting key freezing rain factors

Freezing rain poses significant challenges to power systems, particularly in terms of safety and operational efficiency. This study introduces the latest NASA Earth Exchange Global Daily Downscaled Projections dataset, NEX-GDDP-CMIP6, which enhances the spatial resolution compared to conventional CMIP6 models, thereby offering new potentials for high-resolution climate modeling. Using this advanced dataset, we conducted a comparative analysis to assess its performance in simulating key meteorological factors relevant to freezing rain in Guizhou, China—a region known for its complex terrain and susceptibility to winter icing events. Our analysis indicates that NEX-GDDP-CMIP6 more accurately simulates surface air temperature (tas) and relative humidity (hurs) over complex terrains compared to generic CMIP6 models, especially the best multi-model ensemble (BMME). The BMME projections show a notable decrease in freezing rain days in January in Guizhou, from an average of 12 to 4 by the century’s end (2071–2100), alongside a substantial decrease in the affected area. Additionally, the study highlights that the position of the Yunnan-Guizhou quasi-stationary front (YGQSF) remains unchanged under different emission scenarios. Only minor changes in intensity are observed in small areas, with the equivalent potential temperature gradient decreasing from 0.2 K·km⁻¹ to 0.1 K·km⁻¹. Concurrently, tas and tasmin exhibit a uniform warming trend. This study projects a shrinkage of the winter ice-prone zone in Guizhou, associated with escalated emission levels, with the remaining impacted region retreating to the province’s western portion by the end of this century. Overall, our research underscores the importance of high-resolution datasets like NEX-GDDP-CMIP6 for accurate climate projections and informs regional adaptation strategies, as its projection aligns with recent trends of decreased icing events.