Changes in the End-of-Summer Snow Line Altitude of Summer-Accumulation-Type Glaciers in the Eastern Tien Shan Mountains from 1994 to 2016

Abstract

For summer-accumulation-type glaciers, the glaciological literature is lacking studies on determining the snow line altitude (SLA) from optical images at the end of the summer as an indicator of the equilibrium line altitude (ELA). This paper presents a workflow for extracting the SLA from Landsat images based on the variation in the albedo with the altitude in the central line area of glaciers. The correlation of >0.8 at the 99% confidence level between the retrieved SLAs with ELAs derived from the interpolation of ground-based, mass balance measurements indicated that the workflow can be applied to derive the SLA from end-of-summer satellite data as an indicator of ELA. The ELA was under-estimated by the calculated SLA. The relationship between the end-of-summer SLA and the ELA depends on the intensity of glacier melting. Subsequently, the workflow was applied to the seven glaciers in the Eastern Tien Shan Mountains, and a time series of the SLA was obtained using 12 end-of-summer Landsat scenes from 1994 to 2016. Over the whole study period, a mean SLA of 4011.6 ± 20.7 m above sea level (a.s.l.) was derived for the seven investigated glaciers, and an increasing SLA was demonstrated. The increase in SLAs was consistent for the seven glaciers from 1994 to 2016. Concerning the spatial variability, the east‒west difference was prominent, and these differences exhibited a decreasing trend. The average SLA of each glacier is more influenced by its morpho-topographic variables. The interannual variations in the average SLA are mainly driven by the increasing summer air temperature, and the high correlation with the cumulative summer solid precipitation reflects the characteristics of the summer-accumulation-type glaciers.

Monitoring Rock Desert Formation Caused by Ice–Snow Melting in the Qinghai-Tibet Plateau Using an Optimized Remote Sensing Technique: A Case Study of Yushu Prefecture

“…The snow line observed by remote sensing images is the Seasonal Snow Line, also called Transient Snow Line. This changes with the seasons, it is low in winter and high in summer [27]. The snow line at the end of the melting season in a given year is close to the definition of snow line in glaciology, that is, the boundary between the snow-covered area all year round and the maximum melting area in summer.…”

Remote sensing-derived time series of transient snowline altitudes for High Mountain Asia, 1986–2021

“…Nevertheless, individual outliers reach up above 7000 m a.s.l.. Although such extreme TSLAs have been reported (Zhao et al, 2016), they highlight that individual erroneous data points are inevitable with our highly automated approach despite careful filtering.…”

“…Davaze et al, 2020), and to disentangle topographic and climatic drivers of glacier change (e.g. Yue et al, 2021).…”

Surface Albedo and Snowline Altitude Estimation Using Optical Satellite Imagery and In Situ Measurements in Muz Taw Glacier, Sawir Mountains

“…The glacier surface albedo variations with altitude can effectively reflect the change of physical composition of the glacier surface. Thus, it is feasible to determine the glacier SLA by the difference in albedo between ice and snow derived from Landsat images at the end of the melt season [29][30][31].…”