How do snow cover fraction change and respond to climate in Altai Mountains of China?

• Published in: International journal of climatology Vol. 42; no. 14; pp. 7213 - 7227
• Main Authors: Qin, Shen, Xiao, Pengfeng, Zhang, Xueliang
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 30-11-2022; Wiley Subscription Services, Inc
• Subjects: Accumulation; Air temperature; Altai Mountains; Climate; Climate change; Climate variability; Correlation; Daily precipitation; Distribution; Elevation; Melting; MODIS; Mountain climates; Mountains; Precipitation; Regional climates; Snow; Snow accumulation; Snow cover; snow cover change; Snow cover data; snow cover fraction; Snowmelt; Spectroradiometers; Temporal variations; Watersheds; Altai Mountains; China
• ISSN: 0899-8418; 1097-0088
• DOI: 10.1002/joc.7640

Investigating the spatial and temporal changes in snow cover over mountain areas is significant for understanding the impact of regional climate variability. In this study, using cloud‐removed snow cover data, which are generated based on Moderate Resolution Imaging Spectroradiometer (MODIS) daily snow cover products, the spatiotemporal changes of snow cover fraction (SCF) and its relationship with temperature and precipitation changes from 2002 to 2020 were examined over Altai Mountains, China. The results demonstrate that the distribution and changes of SCF are highly spatiotemporally heterogeneous. Within a year, the maximum SCF occurs in January at 98.6%, and the minimum appears in July at 8.7%. The annual‐mean SCF shows an increasing trend at 0.09%·annum−1, owing to the significantly increasing SCF in the snow accumulation period at 0.5%·annum−1 and the decreasing SCF in the snow melting period at −0.2%·annum−1. The SCF distribution, as well as its interannual change, is greatly influenced by elevation. During the snow cover period, a positive linear correlation between SCF and elevation is found at 0.02%·m−1 (p < .01). The annual‐mean SCF decreases in the area below 1,200 m, whereas it increases in the area above 1,200 m. Accordingly, the elevation‐dependent SCF results in various SCF distributions on different slopes and watersheds. The SCF shows an apparent pattern in different aspects, with similar SCFs between the north and east aspects and between the west and south aspects but a difference between the northeast aspects and the westsouth aspects. The SCF is negatively correlated with air temperature (r = −0.74, p < 0.01) and positively correlated with precipitation (r = 0.74, p < 0.01). In addition, temperature shows a significant and larger correlation with SCF in both the snow accumulation and melting periods, indicating the major factor of temperature for the changes in SCF.
Both the snow cover fraction (SCF) distribution and its interannual change are highly dependent on the elevation during various periods. The annual mean SCF shows an increasing trend due to its increasing during snow accumulation and decreasing during snow melting. The temperature shows a significant correlation to SCF in both the snow accumulation and melting periods.