Quantifying Snow Albedo Radiative Forcing and Its Feedback during 2003–2016

Lin Xiao,Hongjie Xie,Tao Che,Linling Chen,Liyun Dai

doi:10.3390/rs9090883

Abstract

Snow albedo feedback is one of the most crucial feedback processes that control equilibrium climate sensitivity, which is a central parameter for better prediction of future climate change. However, persistent large discrepancies and uncertainties are found in snow albedo feedback estimations. Remotely sensed snow cover products, atmospheric reanalysis data and radiative kernel data are used in this study to quantify snow albedo radiative forcing and its feedback on both hemispheric and global scales during 2003–2016. The strongest snow albedo radiative forcing is located north of 30°N, apart from Antarctica. In general, it has large monthly variation and peaks in spring. Snow albedo feedback is estimated to be 0.18 ± 0.08 W∙m−2∙°C−1 and 0.04 ± 0.02 W∙m−2∙°C−1 on hemispheric and global scales, respectively. Compared to previous studies, this paper focuses specifically on quantifying snow albedo feedback and demonstrates three improvements: (1) used high spatial and temporal resolution satellite-based snow cover data to determine the areas of snow albedo radiative forcing and feedback; (2) provided detailed information for model parameterization by using the results from (1), together with accurate description of snow cover change and constrained snow albedo and snow-free albedo data; and (3) effectively reduced the uncertainty of snow albedo feedback and increased its confidence level through the block bootstrap test. Our results of snow albedo feedback agreed well with other partially observation-based studies and indicate that the 25 Coupled Model Intercomparison Project Phase 5 (CMIP5) models might have overestimated the snow albedo feedback, largely due to the overestimation of surface albedo change between snow-covered and snow-free surface in these models.

Highlights

Introduction1880–2012 [1], with strong warming signals appearing at high northern latitudes [2,3,4]
The globally averaged surface temperature has increased by 0.85 ◦ C over the period of1880–2012 [1], with strong warming signals appearing at high northern latitudes [2,3,4].This is known as the Arctic amplification [5,6,7]
It is impossible to separate the contribution of snow or ice albedo feedback, as well as their uncertainties. Being motivated by these scientific findings and limitations, this study focuses on the quantification of snow albedo feedback by remotely sensed snow cover products of Moderate Resolution Imaging Spectroradiometer (MODIS) (MOD10C1 and MYD10C1), atmospheric reanalysis data and radiative kernel data

Summary

Introduction

1880–2012 [1], with strong warming signals appearing at high northern latitudes [2,3,4]. This is known as the Arctic amplification [5,6,7]. One of the main contributions to the amplified warming is perhaps the positive surface albedo feedback [8,9,10], primarily snow and ice albedo feedback. 2017, 9, 883 refers to bare ice, melting ice (mainly includes sea ice, glaciers and ice caps), snow-covered ice, open water, etc. A central task of climate change research is to quantify the Equilibrium

Methods

Results

Discussion

Conclusion