The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study
Satellite observations of microwave brightness temperatures between 19 GHz and 85 GHz are the main data sources for operational sea-ice monitoring and retrieval of ice concentrations. However, microwave brightness temperatures depend on the emissivity of snow and ice, which is subject to pronounced...
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2014
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Online Access: | https://oceanrep.geomar.de/id/eprint/26951/ https://oceanrep.geomar.de/id/eprint/26951/1/tc-8-891-2014.pdf https://doi.org/10.5194/tc-8-891-2014 |
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ftoceanrep:oai:oceanrep.geomar.de:26951 2023-05-15T13:36:45+02:00 The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study Willmes, Sascha Nicolaus, Marcel Haas, Christian 2014 text https://oceanrep.geomar.de/id/eprint/26951/ https://oceanrep.geomar.de/id/eprint/26951/1/tc-8-891-2014.pdf https://doi.org/10.5194/tc-8-891-2014 en eng Copernicus Publications (EGU) https://oceanrep.geomar.de/id/eprint/26951/1/tc-8-891-2014.pdf Willmes, S., Nicolaus, M. and Haas, C. (2014) The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study. The Cryosphere, 8 (3). pp. 891-904. DOI 10.5194/tc-8-891-2014 <https://doi.org/10.5194/tc-8-891-2014>. doi:10.5194/tc-8-891-2014 cc_by Article PeerReviewed 2014 ftoceanrep https://doi.org/10.5194/tc-8-891-2014 2023-04-07T15:16:51Z Satellite observations of microwave brightness temperatures between 19 GHz and 85 GHz are the main data sources for operational sea-ice monitoring and retrieval of ice concentrations. However, microwave brightness temperatures depend on the emissivity of snow and ice, which is subject to pronounced seasonal variations and shows significant hemispheric contrasts. These mainly arise from differences in the rate and strength of snow metamorphism and melt. We here use the thermodynamic snow model SNTHERM forced by European Re-Analysis (ERA) interim data and the Microwave Emission Model of Layered Snowpacks (MEMLS), to calculate the sea-ice surface emissivity and to identify the contribution of regional patterns in atmospheric conditions to its variability in the Arctic and Antarctic. The computed emissivities reveal a pronounced seasonal cycle with large regional variability. The emissivity variability increases from winter to early summer and is more pronounced in the Antarctic. In the pre-melt period (January–May, July–November) the standard deviations in surface microwave emissivity due to diurnal, regional and inter-annual variability of atmospheric forcing reach up to Δε = 0.034, 0.043, and 0.097 for 19 GHz, 37 GHz and 85 GHz channels, respectively. Between 2000 and 2009, small but significant positive emissivity trends were observed in the Weddell Sea during November and December as well as in Fram Strait during February, potentially related to earlier melt onset in these regions. The obtained results contribute to a better understanding of the uncertainty and variability of sea-ice concentration and snow-depth retrievals in regions of high sea-ice concentrations. Article in Journal/Newspaper Antarc* Antarctic Arctic Fram Strait Sea ice The Cryosphere Weddell Sea OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) Antarctic Arctic The Antarctic Weddell Weddell Sea The Cryosphere 8 3 891 904 |
institution |
Open Polar |
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OceanRep (GEOMAR Helmholtz Centre für Ocean Research Kiel) |
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ftoceanrep |
language |
English |
description |
Satellite observations of microwave brightness temperatures between 19 GHz and 85 GHz are the main data sources for operational sea-ice monitoring and retrieval of ice concentrations. However, microwave brightness temperatures depend on the emissivity of snow and ice, which is subject to pronounced seasonal variations and shows significant hemispheric contrasts. These mainly arise from differences in the rate and strength of snow metamorphism and melt. We here use the thermodynamic snow model SNTHERM forced by European Re-Analysis (ERA) interim data and the Microwave Emission Model of Layered Snowpacks (MEMLS), to calculate the sea-ice surface emissivity and to identify the contribution of regional patterns in atmospheric conditions to its variability in the Arctic and Antarctic. The computed emissivities reveal a pronounced seasonal cycle with large regional variability. The emissivity variability increases from winter to early summer and is more pronounced in the Antarctic. In the pre-melt period (January–May, July–November) the standard deviations in surface microwave emissivity due to diurnal, regional and inter-annual variability of atmospheric forcing reach up to Δε = 0.034, 0.043, and 0.097 for 19 GHz, 37 GHz and 85 GHz channels, respectively. Between 2000 and 2009, small but significant positive emissivity trends were observed in the Weddell Sea during November and December as well as in Fram Strait during February, potentially related to earlier melt onset in these regions. The obtained results contribute to a better understanding of the uncertainty and variability of sea-ice concentration and snow-depth retrievals in regions of high sea-ice concentrations. |
format |
Article in Journal/Newspaper |
author |
Willmes, Sascha Nicolaus, Marcel Haas, Christian |
spellingShingle |
Willmes, Sascha Nicolaus, Marcel Haas, Christian The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study |
author_facet |
Willmes, Sascha Nicolaus, Marcel Haas, Christian |
author_sort |
Willmes, Sascha |
title |
The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study |
title_short |
The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study |
title_full |
The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study |
title_fullStr |
The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study |
title_full_unstemmed |
The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study |
title_sort |
microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study |
publisher |
Copernicus Publications (EGU) |
publishDate |
2014 |
url |
https://oceanrep.geomar.de/id/eprint/26951/ https://oceanrep.geomar.de/id/eprint/26951/1/tc-8-891-2014.pdf https://doi.org/10.5194/tc-8-891-2014 |
geographic |
Antarctic Arctic The Antarctic Weddell Weddell Sea |
geographic_facet |
Antarctic Arctic The Antarctic Weddell Weddell Sea |
genre |
Antarc* Antarctic Arctic Fram Strait Sea ice The Cryosphere Weddell Sea |
genre_facet |
Antarc* Antarctic Arctic Fram Strait Sea ice The Cryosphere Weddell Sea |
op_relation |
https://oceanrep.geomar.de/id/eprint/26951/1/tc-8-891-2014.pdf Willmes, S., Nicolaus, M. and Haas, C. (2014) The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study. The Cryosphere, 8 (3). pp. 891-904. DOI 10.5194/tc-8-891-2014 <https://doi.org/10.5194/tc-8-891-2014>. doi:10.5194/tc-8-891-2014 |
op_rights |
cc_by |
op_doi |
https://doi.org/10.5194/tc-8-891-2014 |
container_title |
The Cryosphere |
container_volume |
8 |
container_issue |
3 |
container_start_page |
891 |
op_container_end_page |
904 |
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1766083475796918272 |