Multiscale Changes in Snow Over the Tibetan Plateau During 1980–2018 Represented by Reanalysis Data Sets and Satellite Observations

Abstract

AbstractThe Tibetan Plateau has experienced substantial warming during the last few decades. As a result, the cryosphere of the Tibetan Plateau, including the snow cover, has shown significant changes. We characterized the changes in snow over the Tibetan Plateau using several snow‐related indices, including snow depth and snow‐covered days based on the MERRA‐2 and JRA‐55 reanalysis data set and passive microwave (MW) satellite observations. The analyses were performed over different time periods—including the last 38, 30, 20, and 10 snow seasons—from 1980 to 2018. The results show that the significant trends in snow depth and snow‐covered days are dependent on both the season and region and vary with the data set and snow‐related index used. There was a clear decrease in the annual maximum consecutive snow‐covered days (CSCDMax), and this was characterized by a later begin time and an earlier end time for both MERRA‐2 and JRA‐55, but only a later begin time for MW during the time period 1980–2018. The changes in CSCDMax were generally dominated by changes in the begin time, which were mainly caused by the increase in the average 2‐m air temperature for November–December. The relatively weak trends in the end time were a result of the combined impact of warmer temperatures and more precipitation in March–April. The CSCDMax averaged over the Tibetan Plateau showed decreasing trends in all studied time periods for JRA‐55 and MW and in the last 38 and 10 snow seasons for MERRA‐2 during the time period 1980–2018.