Elevation dependency of snowfall changes under climate change over the Tibetan Plateau: Evidence from CMIP6 GCMs

Snowfall plays a crucial role in the mountainous cryosphere cycle and is significantly influenced by climate change. This study utilizes the global climate models (GCMs) from Coupled Model Intercomparison Project phase 6 (CMIP6) with multivariate bias correction (MBC) to explore potential future variations in snowfall and its elevation dependency across the Tibetan Plateau (TP). Findings indicate a consistent decline in annual snowfall across the majority of the TP by the end of the century, except for certain high-elevation regions in the northwest. The decreasing trend is projected to intensify with strengthen Shared Socioeconomic Pathway (SSP) scenarios and exhibits elevation dependency below 5000 m. Specifically, under the SSP5-8.5 scenario, snowfall over the TP is expected to decrease by 39.74 % in the far future (2071-2100), with the elevation zone below 2000 m experiencing the most intense decline of approximately 62 %. This trend is largely attributed to the significant warming, which reduces the snow fraction as more precipitation falls as rain rather than snow. This shift is evidenced by the identification of turning points in snow fraction in the mid-2040s to 2050s, coinciding with rapid temperature increases. Furthermore, substantial decreases in future (heavy) snowfall days contribute to the overall reduction in snowfall. However, complex interplay between increased precipitation and temperature effects results in a slight increase in snowfall over high elevation areas in the northern edge. Uncertainty analysis indicates model uncertainty as the dominant source in snowfall projections, accounting for over 50 % of total variance. The projected declines in snowfall and snow fraction, as well as shortened snowfall days could considerably impact the cryosphere, hydrological and ecological systems of the TP.