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Scientists Predict Snowfall Change Mechanism in High Mountain Asia under Global Warming


As a natural solid reservoir, mountain snow is an important part of water resources, providing fresh water for 2 billion people in the world. High Mountain Asia (HMA) is an important distribution area of snow in the middle and low latitude mountains. The dynamic change of snowfall has an extremely important impact on the regional water cycle, energy balance, climate change, and ecological environment. Researchers have revealed the snowfall change mechanism in HMA under global climate change.


In the past half-century, warming trend in HMA is obvious, and the increase of temperature breaks the original natural balance, which may lead to the change of precipitation form, spatial-temporal distribution and rainfall/snow ratio in mountainous areas, change the accumulation / melting rules of glaciers and snow cover in mountainous areas, and then affect the total runoff, the seasonal distribution of runoff and runoff components.


Researchers from Xinjiang Institute of Xinjiang Ecology and Geography, Chinese Academy of Sciences used a new generation of statistical downscaling NEX-GDDP evaluate projected changes in mean snowfall, snowfall days, and snowfall fraction for the years 2070-2099 relative to 1976-2005, under the Representative Concentration Pathway 4.5 (RCP4.5) and 8.5 (RCP8.5) emission scenarios.


An evaluation of the results shows that while NASA’s NEX-GDDP high-resolution daily downscaled dataset can successfully capture the distribution of mean snowfall climatology, it has a strong bias for extreme snowfall indices. In general, the projected increase of temperature under RCP4.5 and RCP8.5-especially in winter-will result in a decrease in snowfall amount (-18.9%, -32.8%), fewer snowfall days (-29.6%, -47.3%), and less precipitation falling as snow (-26.7%, -42.3%). Furthermore, under high emission scenarios, rain-dominated regions are projected to expand 53.9%, while snow-dominated areas will only account for 17.9% of the entire HMA. Spatially, snowfall shows a more robust decline in eastern HMA (e.g., East Tienshan, East Kun Lun, Qilian, South and Eastern Tibet, and Hengduan) than in western HMA (e.g., Hissar Alay, Pamir, and Karakoram). This difference can be attributed to various environmental factors, such as climatology, elevation influences, and the unique seasonal recycle between the two regions.


The research results entitled "Evaluation and projection of snowfall changes in High Mountain Asia based on NASA's NEX-GDDP high- resolution daily downscaled dataset" and "Declining snowfall fraction in the alpine regions, Central Asia" were published in Environmental Research Letters and Scientific Reports.


Articles links: https://iopscience.iop.org/article/10.1088/1748-9326/aba926 


Figure 1 Relative to 1976-2005, projected changes in mean snowfall (S_mean) at spatial (a, b), temporal (c), and regional (d) scales for 2070-2099 under RCP4.5 and RCP8.5 scenarios. The shading in (b) represent the multi-model standard deviations and indicate model uncertainty. 


Figure 2 Distribution of rain-, transitional, and snow-dominated areas in HMA under historical (a) (1970-2005) and RCP4.5 (b) and RCP8.5 (c) (2070-2099) scenarios and their proportions (d) in each period. 



Contact: LIU Jie, Xinjiang Institute of Ecology and Geography

E-mail: liujie@ms.xjb.ac.cn