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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ftdoajarticles:oai:doaj.org/article:7b5b71690f754374b593dd22b51ff1ec 2024-09-15T18:35:38+00:00 Next-generation radiance unfiltering process for the Clouds and the Earth's Radiant Energy System instrument L. Liang W. Su S. Sejas Z. Eitzen N. G. Loeb 2024-04-01T00:00:00Z https://doi.org/10.5194/amt-17-2147-2024 https://doaj.org/article/7b5b71690f754374b593dd22b51ff1ec EN eng Copernicus Publications https://amt.copernicus.org/articles/17/2147/2024/amt-17-2147-2024.pdf https://doaj.org/toc/1867-1381 https://doaj.org/toc/1867-8548 doi:10.5194/amt-17-2147-2024 1867-1381 1867-8548 https://doaj.org/article/7b5b71690f754374b593dd22b51ff1ec Atmospheric Measurement Techniques, Vol 17, Pp 2147-2163 (2024) Environmental engineering TA170-171 Earthwork. Foundations TA715-787 article 2024 ftdoajarticles https://doi.org/10.5194/amt-17-2147-2024 2024-08-05T17:49:34Z 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 ... Article in Journal/Newspaper Sea ice Directory of Open Access Journals: DOAJ Articles Atmospheric Measurement Techniques 17 7 2147 2163 |
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English |
topic |
Environmental engineering TA170-171 Earthwork. Foundations TA715-787 |
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Environmental engineering TA170-171 Earthwork. Foundations TA715-787 L. Liang W. Su S. Sejas Z. Eitzen N. G. Loeb Next-generation radiance unfiltering process for the Clouds and the Earth's Radiant Energy System instrument |
topic_facet |
Environmental engineering TA170-171 Earthwork. Foundations TA715-787 |
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 |
Article in Journal/Newspaper |
author |
L. Liang W. Su S. Sejas Z. Eitzen N. G. Loeb |
author_facet |
L. Liang W. Su S. Sejas Z. Eitzen N. G. Loeb |
author_sort |
L. Liang |
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 |
publisher |
Copernicus Publications |
publishDate |
2024 |
url |
https://doi.org/10.5194/amt-17-2147-2024 https://doaj.org/article/7b5b71690f754374b593dd22b51ff1ec |
genre |
Sea ice |
genre_facet |
Sea ice |
op_source |
Atmospheric Measurement Techniques, Vol 17, Pp 2147-2163 (2024) |
op_relation |
https://amt.copernicus.org/articles/17/2147/2024/amt-17-2147-2024.pdf https://doaj.org/toc/1867-1381 https://doaj.org/toc/1867-8548 doi:10.5194/amt-17-2147-2024 1867-1381 1867-8548 https://doaj.org/article/7b5b71690f754374b593dd22b51ff1ec |
op_doi |
https://doi.org/10.5194/amt-17-2147-2024 |
container_title |
Atmospheric Measurement Techniques |
container_volume |
17 |
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7 |
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2147 |
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2163 |
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1810478819430105088 |