Maps of active layer thickness in northern Alaska by upscaling P-band polarimetric synthetic aperture radar retrievals
Abstract Extensive, detailed information on the spatial distribution of active layer thickness (ALT) in northern Alaska and how it evolves over time could greatly aid efforts to assess the effects of climate change on the region and also help to quantify greenhouse gas emissions generated due to per...
Published in: | Environmental Research Letters |
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Online Access: | http://dx.doi.org/10.1088/1748-9326/ad127f https://iopscience.iop.org/article/10.1088/1748-9326/ad127f https://iopscience.iop.org/article/10.1088/1748-9326/ad127f/pdf |
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crioppubl:10.1088/1748-9326/ad127f 2024-06-02T07:54:16+00:00 Maps of active layer thickness in northern Alaska by upscaling P-band polarimetric synthetic aperture radar retrievals Whitcomb, Jane Chen, Richard Clewley, Daniel Kimball, John S Pastick, Neal J Yi, Yonghong Moghaddam, Mahta NASA 2023 http://dx.doi.org/10.1088/1748-9326/ad127f https://iopscience.iop.org/article/10.1088/1748-9326/ad127f https://iopscience.iop.org/article/10.1088/1748-9326/ad127f/pdf unknown IOP Publishing http://creativecommons.org/licenses/by/4.0 https://iopscience.iop.org/info/page/text-and-data-mining Environmental Research Letters volume 19, issue 1, page 014046 ISSN 1748-9326 journal-article 2023 crioppubl https://doi.org/10.1088/1748-9326/ad127f 2024-05-07T13:56:00Z Abstract Extensive, detailed information on the spatial distribution of active layer thickness (ALT) in northern Alaska and how it evolves over time could greatly aid efforts to assess the effects of climate change on the region and also help to quantify greenhouse gas emissions generated due to permafrost thaw. For this reason, we have been developing high-resolution maps of ALT throughout northern Alaska. The maps are produced by upscaling from high-resolution swaths of estimated ALT retrieved from airborne P-band synthetic aperture radar (SAR) images collected for three different years. The upscaling was accomplished by using hundreds of thousands of randomly selected samples from the SAR-derived swaths of ALT to train a machine learning regression algorithm supported by numerous spatial data layers. In order to validate the maps, thousands of randomly selected samples of SAR-derived ALT were excluded from the training in order to serve as validation pixels; error performance calculations relative to these samples yielded root-mean-square errors (RMSEs) of 7.5–9.1 cm, with bias errors of magnitude under 0.1 cm. The maps were also compared to ALT measurements collected at a number of in situ test sites; error performance relative to the site measurements yielded RMSEs of approximately 11–12 cm and bias of 2.7–6.5 cm. These data are being used to investigate regional patterns and underlying physical controls affecting permafrost degradation in the tundra biome. Article in Journal/Newspaper Active layer thickness permafrost Tundra Alaska IOP Publishing Environmental Research Letters 19 1 014046 |
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Abstract Extensive, detailed information on the spatial distribution of active layer thickness (ALT) in northern Alaska and how it evolves over time could greatly aid efforts to assess the effects of climate change on the region and also help to quantify greenhouse gas emissions generated due to permafrost thaw. For this reason, we have been developing high-resolution maps of ALT throughout northern Alaska. The maps are produced by upscaling from high-resolution swaths of estimated ALT retrieved from airborne P-band synthetic aperture radar (SAR) images collected for three different years. The upscaling was accomplished by using hundreds of thousands of randomly selected samples from the SAR-derived swaths of ALT to train a machine learning regression algorithm supported by numerous spatial data layers. In order to validate the maps, thousands of randomly selected samples of SAR-derived ALT were excluded from the training in order to serve as validation pixels; error performance calculations relative to these samples yielded root-mean-square errors (RMSEs) of 7.5–9.1 cm, with bias errors of magnitude under 0.1 cm. The maps were also compared to ALT measurements collected at a number of in situ test sites; error performance relative to the site measurements yielded RMSEs of approximately 11–12 cm and bias of 2.7–6.5 cm. These data are being used to investigate regional patterns and underlying physical controls affecting permafrost degradation in the tundra biome. |
author2 |
NASA |
format |
Article in Journal/Newspaper |
author |
Whitcomb, Jane Chen, Richard Clewley, Daniel Kimball, John S Pastick, Neal J Yi, Yonghong Moghaddam, Mahta |
spellingShingle |
Whitcomb, Jane Chen, Richard Clewley, Daniel Kimball, John S Pastick, Neal J Yi, Yonghong Moghaddam, Mahta Maps of active layer thickness in northern Alaska by upscaling P-band polarimetric synthetic aperture radar retrievals |
author_facet |
Whitcomb, Jane Chen, Richard Clewley, Daniel Kimball, John S Pastick, Neal J Yi, Yonghong Moghaddam, Mahta |
author_sort |
Whitcomb, Jane |
title |
Maps of active layer thickness in northern Alaska by upscaling P-band polarimetric synthetic aperture radar retrievals |
title_short |
Maps of active layer thickness in northern Alaska by upscaling P-band polarimetric synthetic aperture radar retrievals |
title_full |
Maps of active layer thickness in northern Alaska by upscaling P-band polarimetric synthetic aperture radar retrievals |
title_fullStr |
Maps of active layer thickness in northern Alaska by upscaling P-band polarimetric synthetic aperture radar retrievals |
title_full_unstemmed |
Maps of active layer thickness in northern Alaska by upscaling P-band polarimetric synthetic aperture radar retrievals |
title_sort |
maps of active layer thickness in northern alaska by upscaling p-band polarimetric synthetic aperture radar retrievals |
publisher |
IOP Publishing |
publishDate |
2023 |
url |
http://dx.doi.org/10.1088/1748-9326/ad127f https://iopscience.iop.org/article/10.1088/1748-9326/ad127f https://iopscience.iop.org/article/10.1088/1748-9326/ad127f/pdf |
genre |
Active layer thickness permafrost Tundra Alaska |
genre_facet |
Active layer thickness permafrost Tundra Alaska |
op_source |
Environmental Research Letters volume 19, issue 1, page 014046 ISSN 1748-9326 |
op_rights |
http://creativecommons.org/licenses/by/4.0 https://iopscience.iop.org/info/page/text-and-data-mining |
op_doi |
https://doi.org/10.1088/1748-9326/ad127f |
container_title |
Environmental Research Letters |
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19 |
container_issue |
1 |
container_start_page |
014046 |
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1800750520131911680 |