Spatiotemporal variability of glacier changes and their controlling factors in the Kanchenjunga region, Himalaya based on multi-source remote sensing data from 1975 to 2015

摘要

Spatio-temporal behavior of glaciers in the Himalayas has varied greatly in response to reported climate warming and other modulating factors such as topography, debris cover, and glacier morphology. In this paper, 429 glaciers were examined in the Kanchenjunga region in the middle of the Himalayas. Geodetic methods, feature-based image matching, and multi-parametric integrated approaches were used to detect differences of glacier change and the dominant characteristics driving these differences based on digital elevation models (DEMs), Landsat TM/ETM+/OLI images, Envisat/ASAR and Sentinel-1 data. The results showed that the average change rates in glacier area and surface elevation in 1975-2015 were -0.18 ± 0.07% a~(-1) and - 0.32 ± 0.02 m a~(-1), respectively. The rates of areal shrinkage of glaciers and the glacier surface velocity on the northern side of the Himalayan crest were 1.25 and 1.7 times larger than those of the glaciers on the southern slopes, respectively, whereas the rates of glacier thinning were lower in the north than in the south. The temperature increase from 1975 to 2015 caused an overall widespread glacier retreat in the region. However, differences in the topography of the Kanchenjunga region led to spatial variability in glacier changes with discrepancies as large as several times. The features of individual glaciers, such as glacier size, debris cover, and development of ice-contact glacial lakes enhanced the local complexity of glacier change and elusive response behaviors of the glaciers to climate warming led by the different topographic conditions.