Temporal and Spatial Changes in Snow Cover and the Corresponding Radiative Forcing Analysis in Siberia from the 1970s to the 2010s

Lingxue Yu,Tingxiang Liu,Shuwen Zhang

doi:10.1155/2017/9517427

Abstract

In the context of global climate change, the extent of snow cover in Siberia has significantly decreased since the 1970s, especially in spring. The changes of snow cover at middle and high latitudes have significant impacts on the meteorological and hydrological processes because the snow cover can affect the surface energy, water balance, and the development of the atmospheric boundary layer. In this paper, the temporal and spatial changes in snow cover were firstly estimated based on a long time series of remote sensing snow cover data, both showing a decreased trend. Based on this, we estimated the radiative forcing caused by the snow cover changes from the 1970s to the 2010s and compared it with the radiative forcing caused by the vegetation cover changes over the same time period in Siberia, indicating that the snow cover changes in Siberia can accelerate climate warming and the vegetation cover changes here have the opposite effect. Furthermore, the snow cover changes may play a more important role than the vegetation cover changes in regulating the surface radiation balance in Siberia on the regional scale.

Highlights

A large-scale change in snow cover is an indicator of climate change [1]
The snow albedo feedback (SAF) examined in 25 climate change simulations, which participate in the Coupled Model Intercomparison Project version 5 (CMIP5) by Qu and Hall [10], indicates that the SAF strength is strongly correlated with the climatological surface albedo when the ground is covered by snow
In our study, we assume that surface albedo and emissivity at time t on each pixel α(i, j)t and ε(i, j)t are a function of land cover types (x) and snow conditions (y), while y is a function of time t: α (i, j)t = f (x, y), y = f (t), x ∈ (0, 1, 2, . . . , 16), y ∈ (0, 1) (1)

Summary

Introduction

A large-scale change in snow cover is an indicator of climate change [1]. In response to climate warming in recent decades, the snow cover extent in Northern Hemisphere has decreased with high confidence especially in spring according to the satellite records [3,4,5,6,7]. The warming and snow cover changes in high latitude terrestrial areas of the Northern Hemisphere represent important energy feedbacks to climate system [8, 9]. The snow albedo feedback (SAF) examined in 25 climate change simulations, which participate in the Coupled Model Intercomparison Project version 5 (CMIP5) by Qu and Hall [10], indicates that the SAF strength is strongly correlated with the climatological surface albedo when the ground is covered by snow. Accurate monitoring of the changes in snow cover and estimating the climate effects is necessary and essential

Methods

Results

Conclusion