No evidence of widespread decline of snow cover on the Tibetan Plateau over 2000\u20132015

Xiaoyue Wang,Huanjiong Wang,Zhengjia Liu,Chaoyang Wu,Alemu Gonsamo

doi:10.1038/s41598-017-15208-9

Abstract

Understanding the changes in snow cover is essential for biological and hydrological processes in the Tibetan Plateau (TP) and its surrounding areas. However, the changes in snow cover phenology over the TP have not been well documented. Using Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow products and the Interactive Multi-sensor Snow and Ice Mapping System (IMS) data, we reported daily cloud-free snow cover product over the Tibetan Plateau (TP) for 2000–2015. Snow cover start (SCS), melt (SCM) and duration (SCD) dates were calculated for each hydrological year, and their spatial and temporal variations were analyzed with elevation variations. Our results show no widespread decline in snow cover over the past fifteen years and the trends of snow cover phenology over the TP has high spatial heterogeneity. Later SCS, earlier SCM, and thus decreased SCD mainly occurred in the areas with elevation below 3500 m a.s.l., while regions in central and southwestern edges of the TP showed advanced SCS, delayed SCM and consequently longer SCD. The roles of temperature and precipitation on snow cover penology varied in different elevation zones, and the impact of both temperature and precipitation strengthened as elevation increases.

Highlights

Snow cover is an important component of land cover and the rapid accumulation and melting of snow makes it one of the most active natural materials on the Earth’s surface[1]
Based on daily snow depth data acquired from meteorological stations, Zhu et al found that the snow depth over the Tibetan Plateau (TP) decreased after 200223
The changes in snow cover phenology over the whole plateau provided evidence that there is no significant decrease in snow cover (Fig. 1b)

Summary

Introduction

Snow cover is an important component of land cover and the rapid accumulation and melting of snow makes it one of the most active natural materials on the Earth’s surface[1]. Based on the daily snow observation data from meteorological stations, Ke et al examined the variability of snow cover phenology in China during 1952–201017 They found that snow cover significantly started later and melted earlier with the increasing temperature, but SCD did not show significant trend within this time span. Previous studies mainly focused on changes in the extent, duration and depth of snow cover[26,27], while spatial and temporal patterns of snow cover start (SCS) and melt (SCM) dates of the TP have not been well understood. Changes in snow cover phenology may influence the terrestrial ecosystems through altering thaw and freeze dates of the soil[29] They may influence spring time land surface phenological trend over the TP30 as the climate conditions and topographic features of the TP are complex and variable. The spatial and temporal patterns of SCD, SCS and SCM of the TP in different elevation zones were analyzed, and the drivers of SCS and SCM were identified using climate data

Methods

Results

Conclusion