Recessional pattern and surface elevation change of the Parvati Glacier, North-Western Himalaya (1965-2018) using remote sensing

Abstract

ABSTRACT We present a long-term assessment (1965–2018) of recessional and area change patterns as well as the recent decade surface velocity (, 2000–2001 and 2017–2018) and elevation change (, 2003–2016) of the Parvati Glacier, north-western Himalaya. Multi-temporal high (Corona, Hexagon, and PlanetScope) to medium (Land Remote-Sensing Satellite (System, Landsat) Thematic Mapper (TM)/Enhanced Thematic Mapper+ (ETM+)/Operational Land Imager (OLI), Sentinel 2A- Multispectral Instrument (MSI), and Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER)) resolution images from 1965 to 2018 were analysed to evaluate multi-parameters of glacier dynamics. We estimated an average annual recessional rate of 37.5 ± 0.5 m and total area loss of 2.2 ± 0.01 km2 for the Parvati Glacier over the past half-century (i.e. 1965–2018). During 1973–1989, the Parvati Glacier experienced a significant recession (70.9 ± 3.1 m a−1) that resultant into disintegrated of the glacier in two separate glaciers between 1981 and 1989. We observed a higher average recession rate (28.4 ± 1.6 m a−1) of the detached glacier after its disintegrated from the Parvati Glacier (18.7 ± 1.6 m a−1) between 1989 and 2018. However, the debris-covered ice area of the Parvati Glacier (about 12%) increased twice that of the detached glacier (about 6.1%) during 1994–2018. The estimated reveals a substantial slowdown by about 27.7% and about 20% for the Parvati and detached glacier, respectively, during 2000–2001 and 2017–2018. Overall the annual average surface lowering rate (−0.7 ± 0.5 m a−1) for both the glacier has been almost similar during 2003–2016 but varied significantly at altitudinal. Our study shows inconsistency in previously reported recessional rate and observed advance phases in 1976–1989 and 2009–2013 for the Parvati Glacier during almost the same duration of the study. It is mainly ascribed to the misinterpretation of glacier boundaries using the Survey of India (SoI) topographic map of 1962 where glacier boundaries more generalized and by using coarser resolution of Landsat Multispectral Scanner (MSS) images (1970s), particularly for the debris-covered area. Overall, the Parvati Glacier shows a significant recession and frontal area change; and in the recent decades, extensive surface lowering, along with an observable slowdown in glacier and appearance of ice-cliffs in the ablation area collectively point towards substantial glacier degeneration over the period of our analysis.