Evaluation and Projection of the Eurasian Winter Snow Water Equivalent Based on CMIP6 Models

Historical simulation outputs of climate models from the Coupled Model Intercomparison Program Phase 6 (CMIP6), in addition to the GlobSnow monthly Snow Water Equivalent (SWE) products, were used to assess the model performance in the simulation of the Eurasian winter SWE. Most models can reproduce the basic features of the climatological Eurasian winter SWE relatively well. There are significant differences in different models regarding the trend of SWE, but the MultiModel Ensemble (MME) can produce more realistic simulation results. The spatial and temporal characteristics of the winter SWE obtained from the CMIP6 model simulations and observations were analyzed through the Empirical Orthogonal Function (EOF) analysis. The findings suggest that only some CMIP6 models can reproduce the main features of the first eigenvector, whereas MME can reproduce it well. Moreover, MME can reproduce the response of Eurasian SWE to precipitation and surface air temperature during winter. The projection of Eurasian winter SWE in the 21st century was estimated using the CMIP6 MME results under different emission scenarios of Shared Socioeconomic Pathways (SSPs). With regard to the reference period 1995–2014, SWE projections by MME under four scenarios (SSP126, SSP245, SSP370, and SSP585) all exhibited an increasing trend in the northeastern Eurasia continent and a decreasing trend in continental Europe to the west of 90°E. There was minimal difference in SWE variation under the four SSPs in the early 21st century. However, the difference increased in the late 21st century. Further, the amplitudes of the SWE variations and the intermodel uncertainty increased with time. Further analysis revealed that higher temperatures and increased precipitation were conducive to the SWE increase in northeastern Eurasia.