Changes of mountain glaciers on different time scales − a multi-temporal remote sensing data analysis
Glacier changes take place on a regional and/or a catchment scale depending on the dominance of variable system inherent and external factors. In this study we investigate glacier changes in high-mountain Asia and Alaska regions using remote sensing data and examine the influence of potential mechan...
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| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
| Published: |
2017
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| Online Access: | https://opus4.kobv.de/opus4-fau/frontdoor/index/index/docId/8888 https://nbn-resolving.org/urn:nbn:de:bvb:29-opus4-88889 https://opus4.kobv.de/opus4-fau/files/8888/VijaySaurabhThesis.pdf |
| Summary: | Glacier changes take place on a regional and/or a catchment scale depending on the dominance of variable system inherent and external factors. In this study we investigate glacier changes in high-mountain Asia and Alaska regions using remote sensing data and examine the influence of potential mechanisms responsible for such changes. We present 12 year glacier elevation change rates (2000−2012) of the Lahaul-Spiti, and the Jammu and Kashmir (JK) (Karakoram–Himalaya) regions derived from the TanDEM-X and the SRTM C-/X-band DEMs. Maximum thinning rates were observed for the Lahaul-Spiti region, Himalaya (−0.65 ± 0.43 m/yr) compared to the JK West, Himalaya (−0.48 ± 0.53 m/yr) and the JK East, Karakoram (−0.25 ± 0.47 m/yr) regions. All the glaciers in the Lahaul-Spiti and the JK West had either stable or retreating fronts, but 23 glaciers in the JK East surged during 2000−2012. This regional heterogeneity appears to coincide with the climate settings of high-mountain Asia. Although mid-latitude winter westerlies greatly influence the precipitation in these regions, its dominance in the JK East (Karakoram) is much more compared to the Lahaul-Spiti and the JK West, as noted by previous studies. On a catchment scale, we also find heterogeneous elevation change patterns within the same region. Results suggest that the dominance of either the insulating effects of thick debris-cover or enhanced melting at supraglacial ponds and lakes as well as ice cliffs cause this heterogeneity. Radar signal can penetrate into glacier depending on its surface properties and can deteriorate geodetic observations. The TanDEM-X is an X-band radar mission primarily aimed for deriving global digital elevation model and a prime dataset for our study. We empirically determine the extent of X-band signal penetration into glacier by comparing elevations from TanDEM-X DEMs and NASA’s Operation IceBridge campaigns over Columbia Glacier, Alaska. We find that the penetration depth of X-band signal varies 0–4 m in summers and 4–25 m in winters, ... |
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