Across-track extension of retrieved cloud and aerosol properties for the EarthCARE mission: the ACMB-3D product
<p>The narrow cross section of cloud and aerosol properties retrieved by L2 algorithms that operate on data from EarthCARE's nadir-pointing sensors is broadened across-track by an algorithm that is described and demonstrated here. This scene construction algorithm (SCA) consists of four c...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-05-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | https://amt.copernicus.org/articles/16/2319/2023/amt-16-2319-2023.pdf |
| _version_ | 1797833451334795264 |
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| author | Z. Qu H. W. Barker J. N. S. Cole M. W. Shephard |
| author_facet | Z. Qu H. W. Barker J. N. S. Cole M. W. Shephard |
| author_sort | Z. Qu |
| collection | DOAJ |
| description | <p>The narrow cross section of cloud and aerosol properties retrieved by L2 algorithms that operate on data from EarthCARE's nadir-pointing sensors is broadened across-track by an algorithm that is described and demonstrated here. This scene construction algorithm (SCA) consists of four components. At its core is a radiance-matching procedure that works with measurements made by EarthCARE's Multi-Spectral Imager (MSI). In essence, an off-nadir pixel gets filled with retrieved profiles that are associated with a (nearby) nadir pixel whose MSI radiances best match those of the off-nadir pixel. The SCA constructs a 3D array of cloud and aerosol (and surface) properties for entire frames that measure <span class="inline-formula">∼6000</span> km along-track by 150 km across-track (i.e., the MSI's full swath). Constructed domains out to <span class="inline-formula">∼15</span> km across-track on both sides of nadir are used explicitly downstream as input for 3D radiative transfer models that predict top-of-atmosphere (TOA) broadband solar and thermal fluxes and radiances. These quantities are compared to commensurate measurements made by EarthCARE's Broadband Radiometer (BBR), thus facilitating a continuous closure assessment of the retrievals. Three 6000 km <span class="inline-formula">×200</span> km frames of synthetic EarthCARE observations were used to demonstrate the SCA. The main conclusion is that errors in modelled TOA fluxes that stem from use of 3D domains produced by the SCA are expected to be less than <span class="inline-formula">±5</span> W m<span class="inline-formula"><sup>−2</sup></span> and rarely larger than <span class="inline-formula">±10</span> W m<span class="inline-formula"><sup>−2</sup></span>. As such, the SCA, as purveyor of
information needed to run 3D radiative transfer models, should help more
than hinder the radiative closure assessment of EarthCARE's L2 retrievals.</p> |
| first_indexed | 2024-04-09T14:24:20Z |
| format | Article |
| id | doaj.art-d38ac9c56c79410db5fc07ff53358d08 |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-04-09T14:24:20Z |
| publishDate | 2023-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-d38ac9c56c79410db5fc07ff53358d082023-05-04T13:38:08ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482023-05-01162319233110.5194/amt-16-2319-2023Across-track extension of retrieved cloud and aerosol properties for the EarthCARE mission: the ACMB-3D productZ. Qu0H. W. Barker1J. N. S. Cole2M. W. Shephard3Environment and Climate Change Canada, Toronto, ON, CanadaEnvironment and Climate Change Canada, Victoria, ON, CanadaEnvironment and Climate Change Canada, Toronto, ON, CanadaEnvironment and Climate Change Canada, Toronto, ON, Canada<p>The narrow cross section of cloud and aerosol properties retrieved by L2 algorithms that operate on data from EarthCARE's nadir-pointing sensors is broadened across-track by an algorithm that is described and demonstrated here. This scene construction algorithm (SCA) consists of four components. At its core is a radiance-matching procedure that works with measurements made by EarthCARE's Multi-Spectral Imager (MSI). In essence, an off-nadir pixel gets filled with retrieved profiles that are associated with a (nearby) nadir pixel whose MSI radiances best match those of the off-nadir pixel. The SCA constructs a 3D array of cloud and aerosol (and surface) properties for entire frames that measure <span class="inline-formula">∼6000</span> km along-track by 150 km across-track (i.e., the MSI's full swath). Constructed domains out to <span class="inline-formula">∼15</span> km across-track on both sides of nadir are used explicitly downstream as input for 3D radiative transfer models that predict top-of-atmosphere (TOA) broadband solar and thermal fluxes and radiances. These quantities are compared to commensurate measurements made by EarthCARE's Broadband Radiometer (BBR), thus facilitating a continuous closure assessment of the retrievals. Three 6000 km <span class="inline-formula">×200</span> km frames of synthetic EarthCARE observations were used to demonstrate the SCA. The main conclusion is that errors in modelled TOA fluxes that stem from use of 3D domains produced by the SCA are expected to be less than <span class="inline-formula">±5</span> W m<span class="inline-formula"><sup>−2</sup></span> and rarely larger than <span class="inline-formula">±10</span> W m<span class="inline-formula"><sup>−2</sup></span>. As such, the SCA, as purveyor of information needed to run 3D radiative transfer models, should help more than hinder the radiative closure assessment of EarthCARE's L2 retrievals.</p>https://amt.copernicus.org/articles/16/2319/2023/amt-16-2319-2023.pdf |
| spellingShingle | Z. Qu H. W. Barker J. N. S. Cole M. W. Shephard Across-track extension of retrieved cloud and aerosol properties for the EarthCARE mission: the ACMB-3D product Atmospheric Measurement Techniques |
| title | Across-track extension of retrieved cloud and aerosol properties for the EarthCARE mission: the ACMB-3D product |
| title_full | Across-track extension of retrieved cloud and aerosol properties for the EarthCARE mission: the ACMB-3D product |
| title_fullStr | Across-track extension of retrieved cloud and aerosol properties for the EarthCARE mission: the ACMB-3D product |
| title_full_unstemmed | Across-track extension of retrieved cloud and aerosol properties for the EarthCARE mission: the ACMB-3D product |
| title_short | Across-track extension of retrieved cloud and aerosol properties for the EarthCARE mission: the ACMB-3D product |
| title_sort | across track extension of retrieved cloud and aerosol properties for the earthcare mission the acmb 3d product |
| url | https://amt.copernicus.org/articles/16/2319/2023/amt-16-2319-2023.pdf |
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