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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ftdoajarticles:oai:doaj.org/article:d59b28b918614773a610cd719ccce594 2023-05-15T13:48:41+02:00 The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study S. Willmes M. Nicolaus C. Haas 2014-05-01T00:00:00Z https://doi.org/10.5194/tc-8-891-2014 https://doaj.org/article/d59b28b918614773a610cd719ccce594 EN eng Copernicus Publications http://www.the-cryosphere.net/8/891/2014/tc-8-891-2014.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-8-891-2014 https://doaj.org/article/d59b28b918614773a610cd719ccce594 The Cryosphere, Vol 8, Iss 3, Pp 891-904 (2014) Environmental sciences GE1-350 Geology QE1-996.5 article 2014 ftdoajarticles https://doi.org/10.5194/tc-8-891-2014 2022-12-31T13:32:11Z 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 Directory of Open Access Journals: DOAJ Articles Arctic Antarctic The Antarctic Weddell Sea Weddell The Cryosphere 8 3 891 904 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental sciences GE1-350 Geology QE1-996.5 |
spellingShingle |
Environmental sciences GE1-350 Geology QE1-996.5 S. Willmes M. Nicolaus C. Haas The microwave emissivity variability of snow covered first-year sea ice from late winter to early summer: a model study |
topic_facet |
Environmental sciences GE1-350 Geology QE1-996.5 |
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 |
S. Willmes M. Nicolaus C. Haas |
author_facet |
S. Willmes M. Nicolaus C. Haas |
author_sort |
S. Willmes |
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 |
publishDate |
2014 |
url |
https://doi.org/10.5194/tc-8-891-2014 https://doaj.org/article/d59b28b918614773a610cd719ccce594 |
geographic |
Arctic Antarctic The Antarctic Weddell Sea Weddell |
geographic_facet |
Arctic Antarctic The Antarctic Weddell Sea Weddell |
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_source |
The Cryosphere, Vol 8, Iss 3, Pp 891-904 (2014) |
op_relation |
http://www.the-cryosphere.net/8/891/2014/tc-8-891-2014.pdf https://doaj.org/toc/1994-0416 https://doaj.org/toc/1994-0424 1994-0416 1994-0424 doi:10.5194/tc-8-891-2014 https://doaj.org/article/d59b28b918614773a610cd719ccce594 |
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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1766249585608491008 |