Expansion of a glacial lake, Tsho Chubda, Chamkhar Chu Basin, Hindukush Himalaya, Bhutan

Abstract

A wide range of methods for detection of glacial lakes and their expansions using multi-temporal remote sensing images have been employed in the past. This paper presents a framework for semiautomatic detection of glacial lakes and estimation of its expansion in Chamkhar Chu Basin, Hindukush Himalaya, Bhutan, with the help of ASTER multispectral image classifications. Lakes in the glacierized area tend to have a varying spectral response ranging from light blue or green to almost black which makes them difficult to be differentiated from shadows in the region. Detection of glacial lakes has been performed using NDWI technique and support vector machine image classification approach and results were compared. An integrated thermal-optical dataset was generated for applying SVM technique, and results showed that the lakes under cast shadow were accurately detected. Water spread extent of the lake has been estimated and it was observed that the present expansion rate of glacial lake has increased by twofolds from its previous rate in the last decade. The formations, deformations around glacial lake and related geomorphological variations occurring around lake were employed in defining the expansion mechanism of the lake. This study also demonstrates that ASTER data provide the possibility of accurate detections and estimation of water spread of glacial lake without simultaneous field observations.

A regional-scale assessment of Himalayan glacial lake changes using satellite observations from 1990 to 2015

“…Landsat products are an important source of data for climate change studies, and have been widely used in the cryospheric sciences in the Himalaya [Bhardwaj et al, 2015;Bolch et al, 2008;Buchroithner, 1995;Buchroithner and Bolch, 2015;Gardelle et al, 2011;Liu and Mayer, 2015;Robson et al, 2015]. The expansion of glacial lakes in the Bhutan Himalaya (eastern Himalaya) [Jain et al, 2015;Komori, 2008] and in the Mount Everest region of Nepal [Bajracharya and Mool, 2009] were revealed by remote sensing data, but only for several representative lakes. The Chinese Himalaya glacial lakes expanded by 29.7% based on topography maps from 1970s and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images from the 2000s [Wang et al, 2012b].…”

Spatio-Temporal Evolution of Glacial Lakes in the Tibetan Plateau over the Past 30 Years

“…To our best knowledge, about 30 glacial lake datasets or reports have been published in the TP area, each using different extraction methods and data sources [15]. Most of them adopted the supervised classification of normalized difference water index (NDWI) to extract the lake boundaries [13,30,[38][39][40][41][42][43][44][45][46][47][48][49][50][51][52]; some researchers used the linear spectral unmixing method [53,54], while some others used manual interpretation and auxiliary technologies, such as the "global-local" iterative scheme, band ratio threshold condition, integrated nonlocal active contour approach, machine learning models, etc. [14,20,27,[55][56][57][58][59][60][61][62][63][64][65].…”

Changes of glaciers and glacial lakes implying corridor-barrier effects and climate change in the Hengduan Shan, southeastern Tibetan Plateau

“…Glaciers and glacial lakes are key indicators of climate change and variability. In the context of global warming, it is widely accepted that the majority of glaciers on the Tibetan Plateau (TP) and its surroundings have experienced accelerated reduction (Bolch and others, 2012; Yao and others, 2012; Wei and others, 2014; Song and others, 2015; Zemp and others, 2015; Yang and others, 2016) and glacial lakes have increased in both number and area (Bolch and others, 2008; Komori, 2008; Wang and others, 2012, 2013b, 2014; Nie and others, 2013; Jain and others, 2015; Zhang and others, 2015; Song and others, 2016) in recent decades. However, these glaciers and glacial lakes on the TP show strong spatial and temporal heterogeneities, given the diversity of climatic conditions and complex topography.…”