A NEW WEATHER FILTER FOR REDUCING WEATHER EFFECT IN CALCULATING SEA ICE CONCENTRATION FROM AMSR2 DATA
Ice concentration is one of the most fundamental parameters of sea ice which can be calculated from brightness temperatures measured by passive microwave radiometers such as AMSR2 onboard satellites. However, the presence of atmospheric water vapor, cloud liquid water, etc. is likely to increase the...
Published in: | ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences |
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Online Access: | https://doi.org/10.5194/isprs-annals-X-1-W1-2023-793-2023 https://isprs-annals.copernicus.org/articles/X-1-W1-2023/793/2023/ |
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ftcopernicus:oai:publications.copernicus.org:isprs-annals116502 2024-01-07T09:46:36+01:00 A NEW WEATHER FILTER FOR REDUCING WEATHER EFFECT IN CALCULATING SEA ICE CONCENTRATION FROM AMSR2 DATA Cho, K. Naoki, K. 2023-12-04 application/pdf https://doi.org/10.5194/isprs-annals-X-1-W1-2023-793-2023 https://isprs-annals.copernicus.org/articles/X-1-W1-2023/793/2023/ eng eng doi:10.5194/isprs-annals-X-1-W1-2023-793-2023 https://isprs-annals.copernicus.org/articles/X-1-W1-2023/793/2023/ eISSN: 2194-9050 Text 2023 ftcopernicus https://doi.org/10.5194/isprs-annals-X-1-W1-2023-793-2023 2023-12-11T17:24:18Z Ice concentration is one of the most fundamental parameters of sea ice which can be calculated from brightness temperatures measured by passive microwave radiometers such as AMSR2 onboard satellites. However, the presence of atmospheric water vapor, cloud liquid water, etc. is likely to increase the brightness temperatures over open water. As a result, sometimes, certain ice concentrations are calculated over open water covered with heavy clouds. The authors call this kind of area as “false sea ice” and the phenomenon is called the weather effect. In the AMSR2 ice concentration product, a weather filter is used to reduce the weather effect. However, it is known that false sea ice appears occasionally in some areas even in the summertime in AMSR2 ice concentration products. In this study, the authors have modified the original weather filter and added a new weather filter utilizing the following two equations which are TB(23GHzV)<−0.75×(TB(36GHzV)−TB(36GHzH))+253K and TB(36GHzV)−TB(36GHzH) < 57K. If the brightness temperature of the pixel meets the above two equations, we set the ice concentration of the pixel as 0%. By adding the new weather filter, most of the false sea ice that appeared in the ASMR2 ice concentration products could be rejected. JAXA has decided to add this weather filter for producing AMSR2 standard sea ice concentration products. Text Sea ice Copernicus Publications: E-Journals ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences X-1/W1-2023 793 798 |
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Copernicus Publications: E-Journals |
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ftcopernicus |
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English |
description |
Ice concentration is one of the most fundamental parameters of sea ice which can be calculated from brightness temperatures measured by passive microwave radiometers such as AMSR2 onboard satellites. However, the presence of atmospheric water vapor, cloud liquid water, etc. is likely to increase the brightness temperatures over open water. As a result, sometimes, certain ice concentrations are calculated over open water covered with heavy clouds. The authors call this kind of area as “false sea ice” and the phenomenon is called the weather effect. In the AMSR2 ice concentration product, a weather filter is used to reduce the weather effect. However, it is known that false sea ice appears occasionally in some areas even in the summertime in AMSR2 ice concentration products. In this study, the authors have modified the original weather filter and added a new weather filter utilizing the following two equations which are TB(23GHzV)<−0.75×(TB(36GHzV)−TB(36GHzH))+253K and TB(36GHzV)−TB(36GHzH) < 57K. If the brightness temperature of the pixel meets the above two equations, we set the ice concentration of the pixel as 0%. By adding the new weather filter, most of the false sea ice that appeared in the ASMR2 ice concentration products could be rejected. JAXA has decided to add this weather filter for producing AMSR2 standard sea ice concentration products. |
format |
Text |
author |
Cho, K. Naoki, K. |
spellingShingle |
Cho, K. Naoki, K. A NEW WEATHER FILTER FOR REDUCING WEATHER EFFECT IN CALCULATING SEA ICE CONCENTRATION FROM AMSR2 DATA |
author_facet |
Cho, K. Naoki, K. |
author_sort |
Cho, K. |
title |
A NEW WEATHER FILTER FOR REDUCING WEATHER EFFECT IN CALCULATING SEA ICE CONCENTRATION FROM AMSR2 DATA |
title_short |
A NEW WEATHER FILTER FOR REDUCING WEATHER EFFECT IN CALCULATING SEA ICE CONCENTRATION FROM AMSR2 DATA |
title_full |
A NEW WEATHER FILTER FOR REDUCING WEATHER EFFECT IN CALCULATING SEA ICE CONCENTRATION FROM AMSR2 DATA |
title_fullStr |
A NEW WEATHER FILTER FOR REDUCING WEATHER EFFECT IN CALCULATING SEA ICE CONCENTRATION FROM AMSR2 DATA |
title_full_unstemmed |
A NEW WEATHER FILTER FOR REDUCING WEATHER EFFECT IN CALCULATING SEA ICE CONCENTRATION FROM AMSR2 DATA |
title_sort |
new weather filter for reducing weather effect in calculating sea ice concentration from amsr2 data |
publishDate |
2023 |
url |
https://doi.org/10.5194/isprs-annals-X-1-W1-2023-793-2023 https://isprs-annals.copernicus.org/articles/X-1-W1-2023/793/2023/ |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
eISSN: 2194-9050 |
op_relation |
doi:10.5194/isprs-annals-X-1-W1-2023-793-2023 https://isprs-annals.copernicus.org/articles/X-1-W1-2023/793/2023/ |
op_doi |
https://doi.org/10.5194/isprs-annals-X-1-W1-2023-793-2023 |
container_title |
ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences |
container_volume |
X-1/W1-2023 |
container_start_page |
793 |
op_container_end_page |
798 |
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1787428461522976768 |