Effectively Extracting Iceberg Freeboard Using Bi-Temporal Landsat-8 Panchromatic Image Shadows
The freshwater flux from icebergs into the Southern Ocean plays an important role in the global climate through its impact on the deep-water formation. Large uncertainties exist in the ice volume transported by Southern Ocean icebergs due to the sparse spatial and temporal coverage of observations,...
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Online Access: | https://doi.org/10.3390/rs13030430 |
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ftmdpi:oai:mdpi.com:/2072-4292/13/3/430/ 2023-08-20T04:02:27+02:00 Effectively Extracting Iceberg Freeboard Using Bi-Temporal Landsat-8 Panchromatic Image Shadows Zhenfu Guan Xiao Cheng Yan Liu Teng Li Baogang Zhang Zhitong Yu agris 2021-01-26 application/pdf https://doi.org/10.3390/rs13030430 EN eng Multidisciplinary Digital Publishing Institute https://dx.doi.org/10.3390/rs13030430 https://creativecommons.org/licenses/by/4.0/ Remote Sensing; Volume 13; Issue 3; Pages: 430 iceberg freeboard shadow height Antarctic Landsat-8 optical remote sensing Text 2021 ftmdpi https://doi.org/10.3390/rs13030430 2023-08-01T00:56:30Z The freshwater flux from icebergs into the Southern Ocean plays an important role in the global climate through its impact on the deep-water formation. Large uncertainties exist in the ice volume transported by Southern Ocean icebergs due to the sparse spatial and temporal coverage of observations, especially observations of ice thickness. The iceberg freeboard is a critical geometric parameter for measuring the thickness of an iceberg and then estimating its volume. This study developed a new, highly efficient shadow-height method to precisely measure the freeboard of various icebergs surrounded by sea ice using Landsat-8 Operational Land Imager 15-m bi-temporal panchromatic image shadows at low-solar-elevation angles. We evaluated and validated shadow length precision according to bi-temporal measurements and comparison with the measurements from the unmanned aerial vehicle. We determined freeboard precision according to shadow length precision and solar elevation angle. In our case study area, 4832 available freeboard measuring points with shadow length precision better than 2 pixels covered 376 icebergs with sizes ranging from 0.002 to 0.7 km² and with freeboard ranging from 2.3 to 83.4 m. At the solar elevation angles of 5.2°, the freeboard precision of 64.1% data could reach 1 m and 86.9% could reach 2 m. Our proposed method effectively filled in the data gap of existing freeboard measurement methods. Text Antarc* Antarctic Iceberg* Sea ice Southern Ocean MDPI Open Access Publishing Antarctic Southern Ocean Remote Sensing 13 3 430 |
institution |
Open Polar |
collection |
MDPI Open Access Publishing |
op_collection_id |
ftmdpi |
language |
English |
topic |
iceberg freeboard shadow height Antarctic Landsat-8 optical remote sensing |
spellingShingle |
iceberg freeboard shadow height Antarctic Landsat-8 optical remote sensing Zhenfu Guan Xiao Cheng Yan Liu Teng Li Baogang Zhang Zhitong Yu Effectively Extracting Iceberg Freeboard Using Bi-Temporal Landsat-8 Panchromatic Image Shadows |
topic_facet |
iceberg freeboard shadow height Antarctic Landsat-8 optical remote sensing |
description |
The freshwater flux from icebergs into the Southern Ocean plays an important role in the global climate through its impact on the deep-water formation. Large uncertainties exist in the ice volume transported by Southern Ocean icebergs due to the sparse spatial and temporal coverage of observations, especially observations of ice thickness. The iceberg freeboard is a critical geometric parameter for measuring the thickness of an iceberg and then estimating its volume. This study developed a new, highly efficient shadow-height method to precisely measure the freeboard of various icebergs surrounded by sea ice using Landsat-8 Operational Land Imager 15-m bi-temporal panchromatic image shadows at low-solar-elevation angles. We evaluated and validated shadow length precision according to bi-temporal measurements and comparison with the measurements from the unmanned aerial vehicle. We determined freeboard precision according to shadow length precision and solar elevation angle. In our case study area, 4832 available freeboard measuring points with shadow length precision better than 2 pixels covered 376 icebergs with sizes ranging from 0.002 to 0.7 km² and with freeboard ranging from 2.3 to 83.4 m. At the solar elevation angles of 5.2°, the freeboard precision of 64.1% data could reach 1 m and 86.9% could reach 2 m. Our proposed method effectively filled in the data gap of existing freeboard measurement methods. |
format |
Text |
author |
Zhenfu Guan Xiao Cheng Yan Liu Teng Li Baogang Zhang Zhitong Yu |
author_facet |
Zhenfu Guan Xiao Cheng Yan Liu Teng Li Baogang Zhang Zhitong Yu |
author_sort |
Zhenfu Guan |
title |
Effectively Extracting Iceberg Freeboard Using Bi-Temporal Landsat-8 Panchromatic Image Shadows |
title_short |
Effectively Extracting Iceberg Freeboard Using Bi-Temporal Landsat-8 Panchromatic Image Shadows |
title_full |
Effectively Extracting Iceberg Freeboard Using Bi-Temporal Landsat-8 Panchromatic Image Shadows |
title_fullStr |
Effectively Extracting Iceberg Freeboard Using Bi-Temporal Landsat-8 Panchromatic Image Shadows |
title_full_unstemmed |
Effectively Extracting Iceberg Freeboard Using Bi-Temporal Landsat-8 Panchromatic Image Shadows |
title_sort |
effectively extracting iceberg freeboard using bi-temporal landsat-8 panchromatic image shadows |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2021 |
url |
https://doi.org/10.3390/rs13030430 |
op_coverage |
agris |
geographic |
Antarctic Southern Ocean |
geographic_facet |
Antarctic Southern Ocean |
genre |
Antarc* Antarctic Iceberg* Sea ice Southern Ocean |
genre_facet |
Antarc* Antarctic Iceberg* Sea ice Southern Ocean |
op_source |
Remote Sensing; Volume 13; Issue 3; Pages: 430 |
op_relation |
https://dx.doi.org/10.3390/rs13030430 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/rs13030430 |
container_title |
Remote Sensing |
container_volume |
13 |
container_issue |
3 |
container_start_page |
430 |
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1774712897578991616 |