Changes of snowfall under warming in the Tibetan Plateau

Snowfall is a critical part of the hydrological system in high-altitude regions and strongly impacted by climate change. This study uses a threshold temperature method to estimate spatial and temporal variations of snowfall at 71 stations across the Tibetan Plateau from 1960 to 2014. Regional air temperature and precipitation have increased by 0.039°C/yr, and 1.43 mm/yr, respectively. While warming rates have been fairly uniform across the plateau, spatial variations in snowfall trends are large, with decreases in the eastern and northeastern areas but increases at higher elevations in the center and west. Region-wide snowfall increased during 1961–1990 and 1971–2000 but decreased in 1981–2010 and 1991–2014. Wintertime snowfall has increased, but summer snowfall has decreased. These divergent trends can be explained because maximum snowfall is recorded at temperatures between 1 and 2°C. Above/below this threshold snowfall usually decreases/increases with increased warming. Although maximum snowfall temperature is a key factor to understand future snowfall changes, concurrent influences such as changing moisture sources and atmospheric circulation patterns require further research.