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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ftdoajarticles:oai:doaj.org/article:282e924d531f46d980a2525da4395cc3 2024-01-07T09:39:59+01:00 Effectively Extracting Iceberg Freeboard Using Bi-Temporal Landsat-8 Panchromatic Image Shadows Zhenfu Guan Xiao Cheng Yan Liu Teng Li Baogang Zhang Zhitong Yu 2021-01-01T00:00:00Z https://doi.org/10.3390/rs13030430 https://doaj.org/article/282e924d531f46d980a2525da4395cc3 EN eng MDPI AG https://www.mdpi.com/2072-4292/13/3/430 https://doaj.org/toc/2072-4292 doi:10.3390/rs13030430 2072-4292 https://doaj.org/article/282e924d531f46d980a2525da4395cc3 Remote Sensing, Vol 13, Iss 3, p 430 (2021) iceberg freeboard shadow height Antarctic Landsat-8 optical remote sensing Science Q article 2021 ftdoajarticles https://doi.org/10.3390/rs13030430 2023-12-10T01:42:59Z 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. Article in Journal/Newspaper Antarc* Antarctic Iceberg* Sea ice Southern Ocean Directory of Open Access Journals: DOAJ Articles Antarctic Southern Ocean Remote Sensing 13 3 430 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
iceberg freeboard shadow height Antarctic Landsat-8 optical remote sensing Science Q |
spellingShingle |
iceberg freeboard shadow height Antarctic Landsat-8 optical remote sensing Science Q 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 Science Q |
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 |
Article in Journal/Newspaper |
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 |
MDPI AG |
publishDate |
2021 |
url |
https://doi.org/10.3390/rs13030430 https://doaj.org/article/282e924d531f46d980a2525da4395cc3 |
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, Vol 13, Iss 3, p 430 (2021) |
op_relation |
https://www.mdpi.com/2072-4292/13/3/430 https://doaj.org/toc/2072-4292 doi:10.3390/rs13030430 2072-4292 https://doaj.org/article/282e924d531f46d980a2525da4395cc3 |
op_doi |
https://doi.org/10.3390/rs13030430 |
container_title |
Remote Sensing |
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13 |
container_issue |
3 |
container_start_page |
430 |
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1787430309238669312 |