Assessment of multispectral glacier mapping methods and derivation of glacier area changes, 1978–2002, in the central Southern Alps, New Zealand, from ASTER satellite data, field survey and existing inventory data
| Autor: | EF Gjermundsen, Renaud Mathieu, Trevor Chinn, Andreas Kääb, B. B. Fitzharris, Jon Ove Hagen |
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| Rok vydání: | 2011 |
| Předmět: |
010506 paleontology
geography geography.geographical_feature_category 010504 meteorology & atmospheric sciences Multispectral image Data field Glacier Snow 01 natural sciences Glaciology Glacier mass balance Advanced Spaceborne Thermal Emission and Reflection Radiometer Period (geology) Physical geography Geomorphology Geology 0105 earth and related environmental sciences Earth-Surface Processes |
| Zdroj: | Journal of Glaciology. 57:667-683 |
| ISSN: | 1727-5652 0022-1430 |
| DOI: | 10.3189/002214311797409749 |
| Popis: | We have measured the glacier area changes in the central Southern Alps, New Zealand, between 1978 and 2002 and have compiled the 2002 glacier outlines using an image scene from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Three automated classification methods were tested: (1) band ratio, (2) normalized-difference snow index and (3) supervised classification. The results were compared with the glacier outlines photo-interpreted from the ASTER data, and were further validated using GPS-aided field mapping of selected test glaciers. The ASTER 3/4 band ratio provided the best results. However, all the classification methods failed to extract extensive debris-covered parts of the glaciers. Therefore, the photo-interpreted 2002 outlines were used when comparing with the existing 1978 glacier inventory derived from aerial photographs. Our results show a ∼17% reduction of glacier area, mainly driven by the retreat of the large valley glaciers. Despite the large climatic gradient from west to east, glaciers on both sides of the Main Divide lost similar percentages of area, except Franz Josef and Fox Glaciers which advanced. Smaller glaciers were found to have changed very little in the study period. |
| Databáze: | OpenAIRE |
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