Snow and glacier cover assessment in the high mountains of Sikkim Himalaya

Abstract

Abstract:This study highlights the assessment of snow and glacier cover for possible inferences of global climate change impacts in high mountains like the Himalaya. The test catchment of the River Tista lies in the Sikkim state of the Indian Himalayan region, with steep mountains crossing nearly all ecozones, from subtropical to glacial. River flows are highly fluctuating, especially during the peak rainy season and snowmelt periods. Annual rainfall patterns are nonuniform and can cause large floods. Runoff and discharge downstream are highly dependent upon snow and glacier extent. The temporary storage of frozen water brings about a delay in seasonal runoff. Snow cover built up in the higher regions during the winter months melts in the spring-summer-autumn cycles and contributes to groundwater recharge. A spatial baseline inventory of snow cover/glacier, the permanent snowline and its short-term temporal changes in the remote high-mountain areas have been analysed using multidate Indian Remote Sensing Satellite data of 1992 to 1997. A geographic information system-based overlay has led to inferences on snow cover characteristics and the alignment, dimension, slope disposition, heights of the snout and associated features of each of the glaciers. Snow and glacier recession are to be monitored in future on a long-term basis to derive correlations with climate-change parameters.

Detecting the equilibrium‐line altitudes of New Zealand glaciers using ASTER satellite images

“…Mapping glacier boundaries has been carried out successfully using various techniques: (1) photo-interpretation and manual delineation on colour composites (Williams et al 1997;Khromova et al 2006); (2) image segmentation (or thresholding) of principal components (Sidjak & Wheat 1999), single bands (e.g., TM3-Bronge & Bronge 1999), single band ratios (e.g., TM4/TM5- Bayr et al 1994;Paul et al 2002;Bolch 2007;TM3/TM5-Rott 1994;andreassen et al 2008;aSTeR 3/aSTeR4-Kääb et al 2003;aSTeR2/aSTeR4-Paul et al 2007), or spectral indices (e.g., NdSi-hall et al 2001 ;Krishna 2005;Silverio & Jaquet 2005;Racoviteanu et al 2008a;Keshri et al 2009); (3) unsupervised and supervised classifications (e.g., ISOdaTa, max. likelihood algorithms-aniya et al 1996;Li et al 1998).…”

“…While both targets are very bright in the visible, the short wave infrared domain used in the ratio (1.6-1.7 µm) is a region where clouds are highly reflective while snow and ice absorbs most of the electromagnetic energy. Of several band ratios, several authors found the NdSi the best performers in delineating ice/snow from other targets (Krishna 2005;Racoviteanu et al 2008a).…”

Spatial patterns in glacier characteristics and area changes from 1962 to 2006 in the Kanchenjunga–Sikkim area, eastern Himalaya

“…A new Landsat-based inventory has been complied using imagery from 1999 to 2003 that, along with the current study, may help improve the accuracy in some areas of RGI (Nuimura et al, 2014). Some other regional glacier inventories have been constructed in the past, for example for the western part of the Himalaya (e.g., Kamp et al, 2011;Bhambri et al, 2011;Frey et al, 2012), but only a few are available for the eastern extremity of the Himalaya (e.g., Krishna, 2005;Basnett et al, 2013;Bajracharya et al, 2014;Kulkarni and Narain, 1990). The use of remote sensing for glacier mapping in this area is limited by frequent cloud cover and sensor saturation due to unsuitable gain settings and the persistence of seasonal snow, which hampers quality satellite image acquisition.…”

Melting of major Glaciers in the western Himalayas: evidence of climatic changes from long term MSU derived tropospheric temperature trend (1979–2008)

“…It is observed that a decrease of 578 m occurred in the last century (between 1990 and 2001) (Kulkarni et al, 2005). The large-scale retreat or mass loss of the Himalayan glaciers has a potentially huge impact on the available freshwater resources throughout Asia (Krishna, 2005;Rees and Collins, 2006;Kehrwald et al, 2008;Winiger et al, 2005), which may cause major socio-economic problems. The analysis of the ice-cores and snow from Tibet-Himalaya region show recent climate changes and influence of dust storms and anthropogenic activities Kang et al, 2001;Xu et al, 2007;Lee et al, 2008).…”