EXPLOITING SENTINEL-1 AMPLITUDE DATA FOR GLACIER SURFACE VELOCITY FIELD MEASUREMENTS: FEASIBILITY DEMONSTRATION ON BALTORO GLACIER
The leading idea of this work is to continuously retrieve glaciers surface velocity through SAR imagery, in particular using the amplitude data from the new ESA satellite sensor Sentinel-1 imagery. These imagery key aspects are the free access policy, the very short revisit time (down to 6 days wi...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2016-06-01
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| Series: | The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences |
| Online Access: | https://www.int-arch-photogramm-remote-sens-spatial-inf-sci.net/XLI-B7/783/2016/isprs-archives-XLI-B7-783-2016.pdf |
| Summary: | The leading idea of this work is to continuously retrieve glaciers surface velocity through SAR imagery, in particular using the amplitude
data from the new ESA satellite sensor Sentinel-1 imagery. These imagery key aspects are the free access policy, the very short revisit
time (down to 6 days with the launch of the Sentinel-1B satellite) and the high amplitude resolution (up to 5 m). In order to verify
the reliability of the proposed approach, a first experiment has been performed using Sentinel-1 imagery acquired over the Karakoram
mountain range (North Pakistan) and Baltoro and other three glaciers have been investigated. During this study, a stack of 11 images
acquired in the period from October 2014 to September 2015 has been used in order to investigate the potentialities of the Sentinel-1
SAR sensor to retrieve the glacier surface velocity every month. The aim of this test was to measure the glacier surface velocity between
each subsequent pair, in order to produce a time series of the surface velocity fields along the investigated period. The necessary coregistration
procedure between the images has been performed and subsequently the glaciers areas have been sampled using a regular
grid with a 250 × 250 meters posting. Finally the surface velocity field has been estimated, for each image pair, using a template
matching procedure, and an outlier filtering procedure based on the signal to noise ratio values has been applied, in order to exclude
from the analysis unreliable points. The achieved velocity values range from 10 to 25 meters/month and they are coherent to those
obtained in previous studies carried out on the same glaciers and the results highlight that it is possible to have a continuous update
of the glacier surface velocity field through free Sentinel-1 imagery, that could be very useful to investigate the seasonal effects on the
glaciers fluid-dynamics. |
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| ISSN: | 1682-1750 2194-9034 |