Combined SMAP–SMOS thin sea ice thickness retrieval
The spaceborne passive microwave sensors Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) provide brightness temperature data in the L band (1.4 GHz). At this low frequency the atmosphere is close to transparent and in polar regions the thickness of thin sea ice can be der...
Published in: | The Cryosphere |
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Copernicus Publications
2019
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ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00003058 2023-05-15T18:17:10+02:00 Combined SMAP–SMOS thin sea ice thickness retrieval Paţilea, Cătălin Heygster, Georg Huntemann, Marcus Spreen, Gunnar 2019-02 electronic https://doi.org/10.5194/tc-13-675-2019 https://noa.gwlb.de/receive/cop_mods_00003058 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00003016/tc-13-675-2019.pdf https://tc.copernicus.org/articles/13/675/2019/tc-13-675-2019.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-13-675-2019 https://noa.gwlb.de/receive/cop_mods_00003058 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00003016/tc-13-675-2019.pdf https://tc.copernicus.org/articles/13/675/2019/tc-13-675-2019.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2019 ftnonlinearchiv https://doi.org/10.5194/tc-13-675-2019 2022-02-08T23:00:47Z The spaceborne passive microwave sensors Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) provide brightness temperature data in the L band (1.4 GHz). At this low frequency the atmosphere is close to transparent and in polar regions the thickness of thin sea ice can be derived. SMOS measurements cover a large incidence angle range, whereas SMAP observes at a fixed 40∘ incidence angle. By using brightness temperatures at a fixed incidence angle obtained directly (SMAP), or through interpolation (SMOS), thin sea ice thickness retrieval is more consistent as the incidence angle effects do not have to be taken into account. Here we transfer a retrieval algorithm for the thickness of thin sea ice (up to 50 cm) from SMOS data at 40 to 50∘ incidence angle to the fixed incidence angle of SMAP. The SMOS brightness temperatures (TBs) at a given incidence angle are estimated using empirical fit functions. SMAP TBs are calibrated to SMOS to provide a merged SMOS–SMAP sea ice thickness product. The new merged SMOS–SMAP thin ice thickness product was improved upon in several ways compared to previous thin ice thickness retrievals. (i) The combined product provides a better temporal and spatial coverage of the polar regions due to the usage of two sensors. (ii) The radio frequency interference (RFI) filtering method was improved, which results in higher data availability over both ocean and sea ice areas. (iii) For the intercalibration between SMOS and SMAP brightness temperatures the root mean square difference (RMSD) was reduced by 30 % relative to a prior attempt. (iv) The algorithm presented here allows also for separate retrieval from any of the two sensors, which makes the ice thickness dataset more resistant against failure of one of the sensors. A new way to estimate the uncertainty of ice thickness retrieval was implemented, which is based on the brightness temperature sensitivities. Article in Journal/Newspaper Sea ice The Cryosphere Niedersächsisches Online-Archiv NOA The Cryosphere 13 2 675 691 |
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Niedersächsisches Online-Archiv NOA |
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English |
topic |
article Verlagsveröffentlichung |
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article Verlagsveröffentlichung Paţilea, Cătălin Heygster, Georg Huntemann, Marcus Spreen, Gunnar Combined SMAP–SMOS thin sea ice thickness retrieval |
topic_facet |
article Verlagsveröffentlichung |
description |
The spaceborne passive microwave sensors Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) provide brightness temperature data in the L band (1.4 GHz). At this low frequency the atmosphere is close to transparent and in polar regions the thickness of thin sea ice can be derived. SMOS measurements cover a large incidence angle range, whereas SMAP observes at a fixed 40∘ incidence angle. By using brightness temperatures at a fixed incidence angle obtained directly (SMAP), or through interpolation (SMOS), thin sea ice thickness retrieval is more consistent as the incidence angle effects do not have to be taken into account. Here we transfer a retrieval algorithm for the thickness of thin sea ice (up to 50 cm) from SMOS data at 40 to 50∘ incidence angle to the fixed incidence angle of SMAP. The SMOS brightness temperatures (TBs) at a given incidence angle are estimated using empirical fit functions. SMAP TBs are calibrated to SMOS to provide a merged SMOS–SMAP sea ice thickness product. The new merged SMOS–SMAP thin ice thickness product was improved upon in several ways compared to previous thin ice thickness retrievals. (i) The combined product provides a better temporal and spatial coverage of the polar regions due to the usage of two sensors. (ii) The radio frequency interference (RFI) filtering method was improved, which results in higher data availability over both ocean and sea ice areas. (iii) For the intercalibration between SMOS and SMAP brightness temperatures the root mean square difference (RMSD) was reduced by 30 % relative to a prior attempt. (iv) The algorithm presented here allows also for separate retrieval from any of the two sensors, which makes the ice thickness dataset more resistant against failure of one of the sensors. A new way to estimate the uncertainty of ice thickness retrieval was implemented, which is based on the brightness temperature sensitivities. |
format |
Article in Journal/Newspaper |
author |
Paţilea, Cătălin Heygster, Georg Huntemann, Marcus Spreen, Gunnar |
author_facet |
Paţilea, Cătălin Heygster, Georg Huntemann, Marcus Spreen, Gunnar |
author_sort |
Paţilea, Cătălin |
title |
Combined SMAP–SMOS thin sea ice thickness retrieval |
title_short |
Combined SMAP–SMOS thin sea ice thickness retrieval |
title_full |
Combined SMAP–SMOS thin sea ice thickness retrieval |
title_fullStr |
Combined SMAP–SMOS thin sea ice thickness retrieval |
title_full_unstemmed |
Combined SMAP–SMOS thin sea ice thickness retrieval |
title_sort |
combined smap–smos thin sea ice thickness retrieval |
publisher |
Copernicus Publications |
publishDate |
2019 |
url |
https://doi.org/10.5194/tc-13-675-2019 https://noa.gwlb.de/receive/cop_mods_00003058 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00003016/tc-13-675-2019.pdf https://tc.copernicus.org/articles/13/675/2019/tc-13-675-2019.pdf |
genre |
Sea ice The Cryosphere |
genre_facet |
Sea ice The Cryosphere |
op_relation |
The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-13-675-2019 https://noa.gwlb.de/receive/cop_mods_00003058 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00003016/tc-13-675-2019.pdf https://tc.copernicus.org/articles/13/675/2019/tc-13-675-2019.pdf |
op_rights |
https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/tc-13-675-2019 |
container_title |
The Cryosphere |
container_volume |
13 |
container_issue |
2 |
container_start_page |
675 |
op_container_end_page |
691 |
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1766191233640693760 |