Distribution, attribution, and radiative forcing of snow cover changes over China from 1982 to 2013

Unlike large-scale snow cover variation and its effects on the Earth's climate system, regional-scale snow cover and its impacts on surface-atmosphere interaction and the Earth's energy budget have received little attention. This study aims to quantify the distribution and attribution of snow cover changes over mainland China and the associated snow radiative forcing from 1982 to 2013 by using satellite observations at high spatial and temporal resolutions. Driven by decreased temperature and increased precipitation in the accumulation season, the snow cover fraction (SCF) over mainland China shows an increasing trend at 0.29 % decade(-1) during 1982-2013, which is significant at the 0.05 level. The spatial distribution of changes in the SCF over the 32-year study period exhibits a maximum positive change of 31.08 % in the south-eastern Tibetan Plateau (TP) zone and a maximum negative change of 27.49 % in the northwestern Xinjiang arid zone as well as in the western margin area of the TP zone. Induced by overall increased SCF over mainland China, the snow radiative forcing (RFsnow) in clear-sky conditions is shown to have strengthened by 0.21 +/- 0.01 Wm(-2) decade(-1) at the 0.05 significance level during 1982-2013, which indicates that the cooling effects caused by snow cover over mainland China have strengthened since 1982.