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.

中文翻译：

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利用遥感技术研究喜马拉雅西北部帕尔瓦蒂冰川（1965-2018）的衰退模式和地表高程变化

摘要 我们对 Parvati Glacier 的衰退和面积变化模式以及最近十年的地表速度（2000-2001 和 2017-2018）和海拔变化（2003-2016）进行了长期评估（1965-2018） ，喜马拉雅西北部。多时相高（Corona、Hexagon 和 PlanetScope）到中（陆地遥感卫星（系统、Landsat）专题制图仪 (TM)/增强型专题制图仪+ (ETM+)/操作陆地成像仪 (OLI)、Sentinel 2A- 多光谱仪器(MSI) 和先进的星载热发射和反射辐射计 (ASTER)) 分辨率图像从 1965 年到 2018 年进行了分析，以评估冰川动力学的多参数。我们估计帕尔瓦蒂冰川在过去半个世纪（即 1965-2018 年）的年平均衰退率为 37.5 ± 0.5 m，总面积损失为 2.2 ± 0.01 km2。1973 年至 1989 年期间，帕尔瓦蒂冰川经历了一次显着的衰退 (70.9 ± 3.1 ma-1)，导致 1981 年至 1989 年期间两个独立冰川的冰川解体。我们观察到更高的平均衰退率 (28.4 ± 1.6 ma-1 ) 1989 年至 2018 年从帕尔瓦蒂冰川解体后的分离冰川 (18.7 ± 1.6 ma-1)。然而，帕尔瓦蒂冰川的碎片覆盖冰面积（约 12%）增加了分离冰川的两倍（约 6.1%）在 1994-2018 年期间。估计显示，在 2000-2001 年和 2017-2018 年期间，帕尔瓦蒂冰川和分离冰川分别大幅放缓约 27.7% 和约 20%。总体而言，两个冰川的年平均表面下降率 (-0.7 ± 0.5 ma-1) 在 2003-2016 年期间几乎相似，但在海拔高度上变化很大。我们的研究表明，在几乎相同的研究期间，之前报告的衰退率和 1976 年至 1989 年和 2009 年至 2013 年帕瓦蒂冰川的提前阶段不一致。这主要归因于使用 1962 年的印度调查 (SoI) 地形图对冰川边界的误解，其中冰川边界更加概括，并且使用了更粗糙的 Landsat 多光谱扫描仪 (MSS) 图像（1970 年代），特别是对于碎片覆盖的区域。总体而言，帕尔瓦蒂冰川显示出明显的衰退和锋面变化；并且在最近几十年中，广泛的地表降低，以及可观察到的冰川减缓和消融区冰崖的出现，共同表明在我们的分析期间冰川发生了实质性的退化。