Investigation on Glacier Thinning in Baspa, Western Himalaya.
Abstract
Mass balance studies are important to assess the state of glaciers. Previously, numerous field investigations have been carried out in Baspa basin to measure mass balance. However, mass balance data from field are limited to a small number of glaciers and for short durations. Therefore, this study uses geodetic mass balance technique to evaluate the mass loss at decadal scale. Geodetic method involves differencing Digital Elevation Model (DEM) from different years to obtain change in glacier elevation, which will be subsequently used to evaluate mass balance. This study derives mass balance from 2000 to 2014 for 16 glaciers covering a total area of 70 Sq Km. The study uses Shuttle Radar Topography Mission (SRTM) DEM for year 2000 and DEM for year 2014 was derived from Cartosat-1 stereo pair using photogrammetric principles. A Differential Global Positioning System (DGPS) survey was conducted in Baspa basin at different elevation zones to collect Ground Control Points (GCP) with millimeters accuracy. These GCP were used to derive Cartosat DEM. Various corrections were applied before differencing the two DEMs. They were co-registered using an analytical approach to account for horizontal shift. Corrections were also applied to remove the bias due to satellite acquisition geometry. SRTM DEM was acquired in February when the study area was covered by seasonal snow, whereas, Cartosat data was acquired during the ablation season. As the season of data acquisition varies for the two DEM, we have corrected for the bias that could be caused due to seasonal snow. Snowfall data from a meteorological station in the Baspa valley and a local precipitation gradient were used to determine the seasonal snow depth. Further, corrections were applied to account for the bias due to radar penetration in SRTM DEM. Then, the elevation changes were determined by subtracting the two DEMs to estimate mass balance. The figure below shows the change in glacier elevation. These results will be validated with field estimates. This investigation, after validation, will be an important addition in understanding changes in Himalayan glaciers.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFM.C52A..03S
- Keywords:
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- 0720 Glaciers;
- CRYOSPHERE;
- 0746 Lakes;
- CRYOSPHERE;
- 0758 Remote sensing;
- CRYOSPHERE;
- 0762 Mass balance 0764 Energy balance;
- CRYOSPHERE