Next-generation radiance unfiltering process for the Clouds and the Earth's Radiant Energy System instrument
The filtered radiances measured by the Clouds and the Earth's Radiant Energy System (CERES) instruments are converted to shortwave (SW), longwave (LW), and window unfiltered radiances based on regressions developed from theoretical radiative transfer simulations to relate filtered and unfiltere...
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ftcopernicus:oai:publications.copernicus.org:amt113402 2024-09-15T18:35:34+00:00 Next-generation radiance unfiltering process for the Clouds and the Earth's Radiant Energy System instrument Liang, Lusheng Su, Wenying Sejas, Sergio Eitzen, Zachary Loeb, Norman G. 2024-04-17 application/pdf https://doi.org/10.5194/amt-17-2147-2024 https://amt.copernicus.org/articles/17/2147/2024/ eng eng doi:10.5194/amt-17-2147-2024 https://amt.copernicus.org/articles/17/2147/2024/ eISSN: 1867-8548 Text 2024 ftcopernicus https://doi.org/10.5194/amt-17-2147-2024 2024-08-28T05:24:15Z The filtered radiances measured by the Clouds and the Earth's Radiant Energy System (CERES) instruments are converted to shortwave (SW), longwave (LW), and window unfiltered radiances based on regressions developed from theoretical radiative transfer simulations to relate filtered and unfiltered radiances. This paper describes an update to the existing Edition 4 CERES unfiltering algorithm (Loeb et al., 2001), incorporating the most recent developments in radiative transfer modeling, ancillary input datasets, and increased computational and storage capabilities during the past 20 years. Simulations are performed with the updated Moderate Resolution Atmospheric Transmission (MODTRAN) 5.4 version. Over land and snow, the surface bidirectional reflectance distribution function (BRDF) is characterized by a kernel-based representation in the simulations, instead of the Lambertian surface used in the Edition 4 unfiltering process. Radiance unfiltering is explicitly separated into four seasonally dependent land surface groups based on the spectral radiation similarities of different surface types (defined by the International Geosphere-Biosphere Programme); over snow, it is separated into fresh snow, permanent snow, and sea ice. This differs from the Edition 4 unfiltering process where only one set of regressions was used for land and snow, respectively. The instantaneous unfiltering errors are estimated with independent test cases generated from radiative transfer simulations in which the “true” unfiltered radiances from radiative transfer simulations are compared with the unfiltered radiances calculated from the regressions. Overall, the relative errors are mostly within ± 0.5 % for SW, within ± 0.2 % for daytime LW, and within ± 0.1 % for nighttime LW for both CERES Terra Flight Model 1 (FM1) and Aqua FM3 instruments. The unfiltered radiances are converted to fluxes and compared to CERES Edition 4 fluxes. The global mean instantaneous fluxes for Aqua FM3 are reduced by 0.34 to 0.45 W m −2 for SW and increased by ... Text Sea ice Copernicus Publications: E-Journals Atmospheric Measurement Techniques 17 7 2147 2163 |
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Copernicus Publications: E-Journals |
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English |
description |
The filtered radiances measured by the Clouds and the Earth's Radiant Energy System (CERES) instruments are converted to shortwave (SW), longwave (LW), and window unfiltered radiances based on regressions developed from theoretical radiative transfer simulations to relate filtered and unfiltered radiances. This paper describes an update to the existing Edition 4 CERES unfiltering algorithm (Loeb et al., 2001), incorporating the most recent developments in radiative transfer modeling, ancillary input datasets, and increased computational and storage capabilities during the past 20 years. Simulations are performed with the updated Moderate Resolution Atmospheric Transmission (MODTRAN) 5.4 version. Over land and snow, the surface bidirectional reflectance distribution function (BRDF) is characterized by a kernel-based representation in the simulations, instead of the Lambertian surface used in the Edition 4 unfiltering process. Radiance unfiltering is explicitly separated into four seasonally dependent land surface groups based on the spectral radiation similarities of different surface types (defined by the International Geosphere-Biosphere Programme); over snow, it is separated into fresh snow, permanent snow, and sea ice. This differs from the Edition 4 unfiltering process where only one set of regressions was used for land and snow, respectively. The instantaneous unfiltering errors are estimated with independent test cases generated from radiative transfer simulations in which the “true” unfiltered radiances from radiative transfer simulations are compared with the unfiltered radiances calculated from the regressions. Overall, the relative errors are mostly within ± 0.5 % for SW, within ± 0.2 % for daytime LW, and within ± 0.1 % for nighttime LW for both CERES Terra Flight Model 1 (FM1) and Aqua FM3 instruments. The unfiltered radiances are converted to fluxes and compared to CERES Edition 4 fluxes. The global mean instantaneous fluxes for Aqua FM3 are reduced by 0.34 to 0.45 W m −2 for SW and increased by ... |
format |
Text |
author |
Liang, Lusheng Su, Wenying Sejas, Sergio Eitzen, Zachary Loeb, Norman G. |
spellingShingle |
Liang, Lusheng Su, Wenying Sejas, Sergio Eitzen, Zachary Loeb, Norman G. Next-generation radiance unfiltering process for the Clouds and the Earth's Radiant Energy System instrument |
author_facet |
Liang, Lusheng Su, Wenying Sejas, Sergio Eitzen, Zachary Loeb, Norman G. |
author_sort |
Liang, Lusheng |
title |
Next-generation radiance unfiltering process for the Clouds and the Earth's Radiant Energy System instrument |
title_short |
Next-generation radiance unfiltering process for the Clouds and the Earth's Radiant Energy System instrument |
title_full |
Next-generation radiance unfiltering process for the Clouds and the Earth's Radiant Energy System instrument |
title_fullStr |
Next-generation radiance unfiltering process for the Clouds and the Earth's Radiant Energy System instrument |
title_full_unstemmed |
Next-generation radiance unfiltering process for the Clouds and the Earth's Radiant Energy System instrument |
title_sort |
next-generation radiance unfiltering process for the clouds and the earth's radiant energy system instrument |
publishDate |
2024 |
url |
https://doi.org/10.5194/amt-17-2147-2024 https://amt.copernicus.org/articles/17/2147/2024/ |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
eISSN: 1867-8548 |
op_relation |
doi:10.5194/amt-17-2147-2024 https://amt.copernicus.org/articles/17/2147/2024/ |
op_doi |
https://doi.org/10.5194/amt-17-2147-2024 |
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Atmospheric Measurement Techniques |
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7 |
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2147 |
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2163 |
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1810478766524203008 |