Abschlussarbeiten
Glacier volume and mass balance in the Ala Archa National Park (Kyrgyz Ala-Too/Kyrgyzstan)
Art der Abschlussarbeit
Diplomarbeit
Autoren
- Ender, Angela
Betreuer
- Prof. Dr.phil.habil. Manfred Buchroithner
Weitere Betreuer
Universität Zürich, Dr. Bolch
Abstract
The presented work shows a GIS-based investigation on the retreat of mountain glaciers in the Ala Archa National Park (Northern Tien Shan / Kyrgyzstan). The investigation is based on the multitemporal satellite data Corona KH-4A (1964), Corona KH-4B (1971), Hexagon (1973), Landsat TM (1994), ASTER (2003) and RapidEye (2010). Additionally, several aerial photographs (1971, 1988) as well as topographic maps were available. In 1964 there existed 50 glaciers. Some of them disintegrated. This affect is often found where glacier tongues merged in former times and are now these separated. Four glaciers disappeared completely. rnRegarding the glacier area, a shrinking of approx. 18 % between 1964 and 2010 was calculated, with an almost constant rate. In contrast, the degree of debris coverage has increased during the retreat. Recently, the glacial area in the study area ranged over 33.3 km², 6 % of this area is covered by debris. rnSince Corona- and ASTER-imagery contain stereo image pairs, Digital Elevation Models (DEM) were generated. Caused by the location of the study area in the high mountains, further elevation errors occurred, which could be reduced by post-processing. The final elevation errors for Corona (1964 and 1971) were in average ±30 m and ±38 m for non-glacial areas, respectively. The ASTER-DEM show similar accuracies. But due to the generation, they are coarse compared to the small size of the glaciers. Thus, they were rejected. rnBased on these DEM, the specific mass balance was calculated with respect to a SRTM-model from 2000. The balances show different results. Between 1964 and 1971, a positive balance is detected (+0.72 ± 4.3). Between 1971 and 2000 it is negative (-0.40 ± 0.84 m w.e. a-1). rnThe absolute volume was estimate to 1.5 ± 0.1 km³ by using a model for glacier bed calculations. Therefore, the absolute volume was 1.80 ± 0.08 km³ for 1964 and 2.04 ± 0.10 km³ for 1971, respectively. rnIn order to increase the degree of automation a Python-script was developed. This script calculates central branch lines of glaciers based on hydrologic aspects. The absolute volume calculated from each automatic and manual branch lines differs in an amount of only +0.03 km³. Therefore, the approach for this script shows to be applicable for the usage on glaciers.rn
Url/Urn/Doi
kartographie.geo.tu-dresden.de
Zugeordnete Forschungsschwerpunkte
- Geoinformationssysteme für Umweltmonitoring
- Fernerkundungskartographie
Zugeordnete Forschungsprojekte
- Monitoring von Gletschern und Gletscherseen am Mt. Everest, Nepal, mit ASTER-Satellitendaten und Digitalen Geländemodellen (DGM)
Schlagwörter
Glacier volume; Gletscherrückgang
Berichtsjahr
2011