Evaluation of the Global Glacier Inventories and Assessment of Glacier Thickness Changes over North-western Himalaya

The study evaluates the global glacier inventories available for the study area viz., RGI, GAMDAM and ICIMOD, with the newly generated Kashmir University Glacier Inventory (KUGI) for three Himalaya basins; Jhelum, Suru and Chenab in the north-western Himalaya, comprising of 2096 glaciers spread over an area of 3300 km². The KUGI was prepared from the Landsat data supplemented by Digital Elevation Model, Google Earth images and limited field surveys. The KUGI comprises of 154 glaciers in the Jhelum, 328 in the Suru and 1614 in the Chenab basin, corresponding to the glacier area of 85.9 ±11.4 km², 487 ±16.2 km² and 2727 ±90.2 km² respectively. The investigation revealed that most of the glaciers in the study area are <1 km² in size, however, the glaciers in 1-5 km² size class cover most (55.8%) of the glacier area. Majority of the glaciers, both in terms of number and area, are at 4500-5500m asl except in the Jhelum where the glaciers are mostly situated between 4000-5000m asl altitude. The glaciers in the three basins mainly harbor slopes ranging from 10-30°. It was also observed that the southern aspects host more number of large-sized glaciers than the northern aspects. Comparative analyses of the inventories revealed that the GAMDAM ( =0.75) and RGI ( =0.73) inventories are consistent with the KUGI. However, discrepancies were observed in the debris-covered and shadowed glaciers particularly in the ICIMOD inventory. The glacier thickness changes were also estimated for glaciers in the three basins using the Tandem-X and SRTM-C DEMs from 2000 to 2012. The investigation revealed a strong control of glacial morphology, topography, and debris cover on glacier thinning. Glacier thickness change of -1.33±0.8 m a^-1 was observed in the Jhelum basin but a similar glacier thickness change of -1.08±0.7 m a^-1 and -1.09±0.8 m a^-1 was observed in the Suru and Chenab basins respectively. Evaluation of the glacier inventories and assessment of glacier thickness in the data-scarce Himalaya, reported in this article, would constitute a reliable database for research particularly in hydrology, glaciology, and climate change.