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

Xiaona Chen,Tao He,Yunfeng Cao,Shunlin Liang

doi:10.1007/s10584-016-1688-z

Abstract

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.

Highlights

Snow is an integral component of the global climate system
The aim of the present study is to investigate the spatiotemporal variation in snow cover over mainland China and to quantify the associated snow-induced radiative forcing from 1982 to 2013 by using satellite observations with high spatial and temporal resolutions
The spatial distribution of annual mean snow cover fraction (SCF) maps derived from Northern Hemisphere Snow Cover Extent (NHSCE) and Moderate Resolution Imaging Spectroradiometer Satellite (MODIS) were similar during 2001–2013 (Fig. 2a and 2b)

Summary

Introduction

Snow is an integral component of the global climate system. Owing to its high albedo and thermal and water storage properties, snow generates important linkages and feedbacks through its influence on surface energy and moisture fluxes, clouds, precipitation, hydrology, and atmospheric circulation. The Intergovernmental Panel on Climate Change (IPCC) has reported that the snow cover extent (SCE) has obviously declined in the Northern Hemisphere (NH), and it has predicted that anthropogenic global warming will be greatest in northern snow-covered areas (IPCC 2013) Both observations (Brown and Robinson 2011; Derksen and Brown 2012) and climate models (Derksen and Brown 2012; McCabe and Wolock 2009; Roesch and Roeckner 2006) suggest an apparent decline in spring SCE and a strong direct influence of snow cover on the surface–atmosphere energy budget, in the radiative forcing at the surface and the top of atmosphere (TOA). Derksen and Brown (2012) further confirmed that spring SCE reductions in 2008–2012 have even exceeded the Coupled Model Inter-comparison Project Phase 5 (CMIP5) model projections

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Conclusion