Anisotropic radiative transfer in sea ice
The optical properties of sea ice such as albedo and transmittance are governed by strong scattering of light in the sea-ice matrix. Due to its crystal structure, most physical properties of sea ice are anisotropic. Nevertheless, the optical properties of sea ice are treated as isotropic in most mod...
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International Glaciological Society
2014
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ftawi:oai:epic.awi.de:35096 2024-09-15T17:36:00+00:00 Anisotropic radiative transfer in sea ice Katlein, Christian Nicolaus, Marcel Petrich, Chris 2014-03-10 application/pdf https://epic.awi.de/id/eprint/35096/ https://epic.awi.de/id/eprint/35096/1/Talk_Hobart_Katlein.pdf https://hdl.handle.net/10013/epic.43154 https://hdl.handle.net/10013/epic.43154.d001 unknown International Glaciological Society https://epic.awi.de/id/eprint/35096/1/Talk_Hobart_Katlein.pdf https://hdl.handle.net/10013/epic.43154.d001 Katlein, C. orcid:0000-0003-2422-0414 , Nicolaus, M. orcid:0000-0003-0903-1746 and Petrich, C. (2014) Anisotropic radiative transfer in sea ice , International Symposium on Sea Ice in a Changing Environment, Hobart, Tasmania, 10 March 2014 - 14 March 2014 . hdl:10013/epic.43154 EPIC3International Symposium on Sea Ice in a Changing Environment, Hobart, Tasmania, 2014-03-10-2014-03-14International Glaciological Society Conference notRev 2014 ftawi 2024-06-24T04:08:32Z The optical properties of sea ice such as albedo and transmittance are governed by strong scattering of light in the sea-ice matrix. Due to its crystal structure, most physical properties of sea ice are anisotropic. Nevertheless, the optical properties of sea ice are treated as isotropic in most models although existing measurements give a contradicting picture. Understanding radiative transfer and the light-field geometry under sea ice is crucial for correct conversion of radiance data e.g. in AUV or ROV applications. We present ROV-based measurements of irradiance and radiance under summer sea ice of the central Arctic. They allow for insights into the under-ice light field under ponded sea ice and into micro-optical scattering properties of sea ice. Field measurements are interpreted along with numerical radiative transfer calculations, laboratory experiments and microstructure analysis. Our results show that the ratio of synchronous measurements of transmitted irradiance and radiance shows a clear deviation of the angular radiance distribution from the widely used assumption of an isotropic under-ice light field. We show that the angular radiance distribution under sea ice is more downward-directed than commonly assumed. This implies that assuming isotropic conditions under sea ice leads to significant errors in light-field modeling and the interpretation of radiation measurements. The under-ice light field is directly influenced by the anisotropic scattering coefficient of the bottommost sea ice, and the downward-directed radiance distribution causes a deeper light penetration into the ocean under pond-covered ice. Conference Object albedo Sea ice Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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Alfred Wegener Institute for Polar- and Marine Research (AWI): ePIC (electronic Publication Information Center) |
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The optical properties of sea ice such as albedo and transmittance are governed by strong scattering of light in the sea-ice matrix. Due to its crystal structure, most physical properties of sea ice are anisotropic. Nevertheless, the optical properties of sea ice are treated as isotropic in most models although existing measurements give a contradicting picture. Understanding radiative transfer and the light-field geometry under sea ice is crucial for correct conversion of radiance data e.g. in AUV or ROV applications. We present ROV-based measurements of irradiance and radiance under summer sea ice of the central Arctic. They allow for insights into the under-ice light field under ponded sea ice and into micro-optical scattering properties of sea ice. Field measurements are interpreted along with numerical radiative transfer calculations, laboratory experiments and microstructure analysis. Our results show that the ratio of synchronous measurements of transmitted irradiance and radiance shows a clear deviation of the angular radiance distribution from the widely used assumption of an isotropic under-ice light field. We show that the angular radiance distribution under sea ice is more downward-directed than commonly assumed. This implies that assuming isotropic conditions under sea ice leads to significant errors in light-field modeling and the interpretation of radiation measurements. The under-ice light field is directly influenced by the anisotropic scattering coefficient of the bottommost sea ice, and the downward-directed radiance distribution causes a deeper light penetration into the ocean under pond-covered ice. |
format |
Conference Object |
author |
Katlein, Christian Nicolaus, Marcel Petrich, Chris |
spellingShingle |
Katlein, Christian Nicolaus, Marcel Petrich, Chris Anisotropic radiative transfer in sea ice |
author_facet |
Katlein, Christian Nicolaus, Marcel Petrich, Chris |
author_sort |
Katlein, Christian |
title |
Anisotropic radiative transfer in sea ice |
title_short |
Anisotropic radiative transfer in sea ice |
title_full |
Anisotropic radiative transfer in sea ice |
title_fullStr |
Anisotropic radiative transfer in sea ice |
title_full_unstemmed |
Anisotropic radiative transfer in sea ice |
title_sort |
anisotropic radiative transfer in sea ice |
publisher |
International Glaciological Society |
publishDate |
2014 |
url |
https://epic.awi.de/id/eprint/35096/ https://epic.awi.de/id/eprint/35096/1/Talk_Hobart_Katlein.pdf https://hdl.handle.net/10013/epic.43154 https://hdl.handle.net/10013/epic.43154.d001 |
genre |
albedo Sea ice |
genre_facet |
albedo Sea ice |
op_source |
EPIC3International Symposium on Sea Ice in a Changing Environment, Hobart, Tasmania, 2014-03-10-2014-03-14International Glaciological Society |
op_relation |
https://epic.awi.de/id/eprint/35096/1/Talk_Hobart_Katlein.pdf https://hdl.handle.net/10013/epic.43154.d001 Katlein, C. orcid:0000-0003-2422-0414 , Nicolaus, M. orcid:0000-0003-0903-1746 and Petrich, C. (2014) Anisotropic radiative transfer in sea ice , International Symposium on Sea Ice in a Changing Environment, Hobart, Tasmania, 10 March 2014 - 14 March 2014 . hdl:10013/epic.43154 |
_version_ |
1810486565876531200 |