Climatology of snow phenology over the Tibetan plateau for the period 2001-2014 using multisource data

Seasonal snow cover over the Tibetan plateau (TP) has unique features in terms of global snow cover distribution because of the high mountains and vital surface water storage functions in non-humid regions of Southwest China and surrounding Asian countries. Limited by the complex topography and relatively low spatial resolution of satellite observations, the characteristics of snow phenology and the factors for snow phenology changes remain still unclear. Using multisource data for the period 2001-2014, this study quantifies the climatology of snow phenology and explores its attribution factors. The results show that the snow onset date (D-o) and snow end date (D-e) were 4.9 (+/- 7.7) and 108.1 (+/- 5.9) in day of year (DOY), respectively, and the snow duration days (D-d) were 103.2 (+/- 13.4) over the TP during the study period. The characteristics of satellite observed D-d was similar to subzero temperature days derived from ground observations. The 14-year anomalies in snow phenology features regional disparity over the TP, with increased D-d in the central TP and shortened D-d in the Tarim River, endorheic drainage basins, and upper reaches of the Brahmaputra River. In contrast to previous findings in northern mid-latitudes, changes in D-d over the TP during 2001-2014 were mainly induced by anomalies in D-o, which can be further attributed to the declines in accumulation season temperature over the TP.