Automatic mapping and geomorphometry extraction technique for crevasses in geodetic mass-balance calculations at Haig Glacier, Canadian Rockies
Finely resolved geodetic data provide an opportunity to assess the extent and morphology of crevasses and their change over time. Crevasses have the potential to bias geodetic measurements of elevation and mass change unless they are properly accounted for. We developed a framework that automaticall...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Cambridge University Press
2019-12-01
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| Series: | Journal of Glaciology |
| Subjects: | |
| Online Access: | https://www.cambridge.org/core/product/identifier/S0022143019000716/type/journal_article |
| _version_ | 1827994411330437120 |
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| author | Marzieh Foroutan Shawn J. Marshall Brian Menounos |
| author_facet | Marzieh Foroutan Shawn J. Marshall Brian Menounos |
| author_sort | Marzieh Foroutan |
| collection | DOAJ |
| description | Finely resolved geodetic data provide an opportunity to assess the extent and morphology of crevasses and their change over time. Crevasses have the potential to bias geodetic measurements of elevation and mass change unless they are properly accounted for. We developed a framework that automatically maps and extracts crevasse geometry and masks them where they interfere with surface mass-balance assessment. Our study examines airborne light detection and ranging digital elevation models (LiDAR DEMs) from Haig Glacier, which is experiencing a transient response in its crevassed upper regions as the glacier thins, using a self-organizing map algorithm. This method successfully extracts and characterizes ~1000 crevasses, with an overall accuracy of 94%. The resulting map provides insight into stress and flow conditions. The crevasse mask also enables refined geodetic estimates of summer mass balance. From differencing of September and April LiDAR DEMs, the raw LiDAR DEM gives a 9% overestimate in the magnitude of glacier thinning over the summer: −5.48 m compared with a mean elevation change of −5.02 m when crevasses are masked out. Without identification and removal of crevasses, the LiDAR-derived summer mass balance therefore has a negative bias relative to the glaciological surface mass balance. |
| first_indexed | 2024-04-10T04:40:32Z |
| format | Article |
| id | doaj.art-3c47d8fdb05b42b4b2595c7b4c850201 |
| institution | Directory Open Access Journal |
| issn | 0022-1430 1727-5652 |
| language | English |
| last_indexed | 2024-04-10T04:40:32Z |
| publishDate | 2019-12-01 |
| publisher | Cambridge University Press |
| record_format | Article |
| series | Journal of Glaciology |
| spelling | doaj.art-3c47d8fdb05b42b4b2595c7b4c8502012023-03-09T12:40:49ZengCambridge University PressJournal of Glaciology0022-14301727-56522019-12-016597198210.1017/jog.2019.71Automatic mapping and geomorphometry extraction technique for crevasses in geodetic mass-balance calculations at Haig Glacier, Canadian RockiesMarzieh Foroutan0Shawn J. Marshall1https://orcid.org/0000-0002-8300-1388Brian Menounos2https://orcid.org/0000-0002-3370-4392Department of Geography and Environmental Management, University of Waterloo, Waterloo, Canada Department of Geography, University of Calgary, Calgary, CanadaDepartment of Geography, University of Calgary, Calgary, CanadaGeography Program and Natural Resources and Environmental Studies Institute, University of Northern British Columbia, Prince George, CanadaFinely resolved geodetic data provide an opportunity to assess the extent and morphology of crevasses and their change over time. Crevasses have the potential to bias geodetic measurements of elevation and mass change unless they are properly accounted for. We developed a framework that automatically maps and extracts crevasse geometry and masks them where they interfere with surface mass-balance assessment. Our study examines airborne light detection and ranging digital elevation models (LiDAR DEMs) from Haig Glacier, which is experiencing a transient response in its crevassed upper regions as the glacier thins, using a self-organizing map algorithm. This method successfully extracts and characterizes ~1000 crevasses, with an overall accuracy of 94%. The resulting map provides insight into stress and flow conditions. The crevasse mask also enables refined geodetic estimates of summer mass balance. From differencing of September and April LiDAR DEMs, the raw LiDAR DEM gives a 9% overestimate in the magnitude of glacier thinning over the summer: −5.48 m compared with a mean elevation change of −5.02 m when crevasses are masked out. Without identification and removal of crevasses, the LiDAR-derived summer mass balance therefore has a negative bias relative to the glaciological surface mass balance.https://www.cambridge.org/core/product/identifier/S0022143019000716/type/journal_articleCrevassesglaciological instruments and methodsremote sensing |
| spellingShingle | Marzieh Foroutan Shawn J. Marshall Brian Menounos Automatic mapping and geomorphometry extraction technique for crevasses in geodetic mass-balance calculations at Haig Glacier, Canadian Rockies Journal of Glaciology Crevasses glaciological instruments and methods remote sensing |
| title | Automatic mapping and geomorphometry extraction technique for crevasses in geodetic mass-balance calculations at Haig Glacier, Canadian Rockies |
| title_full | Automatic mapping and geomorphometry extraction technique for crevasses in geodetic mass-balance calculations at Haig Glacier, Canadian Rockies |
| title_fullStr | Automatic mapping and geomorphometry extraction technique for crevasses in geodetic mass-balance calculations at Haig Glacier, Canadian Rockies |
| title_full_unstemmed | Automatic mapping and geomorphometry extraction technique for crevasses in geodetic mass-balance calculations at Haig Glacier, Canadian Rockies |
| title_short | Automatic mapping and geomorphometry extraction technique for crevasses in geodetic mass-balance calculations at Haig Glacier, Canadian Rockies |
| title_sort | automatic mapping and geomorphometry extraction technique for crevasses in geodetic mass balance calculations at haig glacier canadian rockies |
| topic | Crevasses glaciological instruments and methods remote sensing |
| url | https://www.cambridge.org/core/product/identifier/S0022143019000716/type/journal_article |
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