A versatile method for computing optimized snow albedo from spectrally fixed radiative variables: VALHALLA v1.0
<p>In climate models, the snow albedo scheme generally calculates only a narrowband or broadband albedo, which leads to significant uncertainties. Here, we present the Versatile ALbedo calculation metHod based on spectrALLy fixed radiative vAriables (VALHALLA version 1.0) to optimize spectral...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2021-11-01
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| Series: | Geoscientific Model Development |
| Online Access: | https://gmd.copernicus.org/articles/14/7329/2021/gmd-14-7329-2021.pdf |
| _version_ | 1819039464971829248 |
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| author | F. Veillon F. Veillon M. Dumont C. Amory C. Amory M. Fructus |
| author_facet | F. Veillon F. Veillon M. Dumont C. Amory C. Amory M. Fructus |
| author_sort | F. Veillon |
| collection | DOAJ |
| description | <p>In climate models, the snow albedo scheme generally calculates only a narrowband or broadband albedo, which leads to significant uncertainties. Here, we present the Versatile ALbedo calculation metHod based on spectrALLy fixed radiative vAriables (VALHALLA version 1.0) to optimize spectral snow albedo calculation. For this optimization, the energy absorbed by the snowpack is calculated by the spectral albedo model Two-streAm Radiative TransfEr in Snow (TARTES) and the spectral irradiance model Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART). This calculation takes into account the spectral characteristics of the incident radiation and the optical properties of the snow based on an analytical approximation of the radiative transfer of snow. For this method, 30 wavelengths, called tie points (TPs), and 16 reference irradiance profiles are calculated to incorporate the absorbed energy and the reference irradiance. The absorbed energy is then interpolated for each wavelength between two TPs with adequate kernel functions derived from radiative transfer theory for snow and the atmosphere. We show that the accuracy of the absorbed energy calculation primarily depends on the adaptation of the irradiance of the reference profile to that of the simulation (absolute difference <span class="inline-formula"><1</span> W m<span class="inline-formula"><sup>−2</sup></span> for broadband absorbed energy and absolute difference <span class="inline-formula"><0.005</span> for broadband albedo).
In addition to the performance in terms of accuracy and calculation time, the method is adaptable to any atmospheric input (broadband, narrowband) and is easily adaptable for integration into a radiative scheme of a global or regional climate model.</p> |
| first_indexed | 2024-12-21T08:53:38Z |
| format | Article |
| id | doaj.art-a681ed54421b457688c6dd9695c0a0e9 |
| institution | Directory Open Access Journal |
| issn | 1991-959X 1991-9603 |
| language | English |
| last_indexed | 2024-12-21T08:53:38Z |
| publishDate | 2021-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Geoscientific Model Development |
| spelling | doaj.art-a681ed54421b457688c6dd9695c0a0e92022-12-21T19:09:37ZengCopernicus PublicationsGeoscientific Model Development1991-959X1991-96032021-11-01147329734310.5194/gmd-14-7329-2021A versatile method for computing optimized snow albedo from spectrally fixed radiative variables: VALHALLA v1.0F. Veillon0F. Veillon1M. Dumont2C. Amory3C. Amory4M. Fructus5Laboratory of Climatology, Department of Geography, SPHERES, University of Liège, Liège, BelgiumUniversité Grenoble Alpes, Université de Toulouse, Météo-France, CNRS, CNRM, Centre d'Etudes de la Neige, 38000 Grenoble, FranceUniversité Grenoble Alpes, Université de Toulouse, Météo-France, CNRS, CNRM, Centre d'Etudes de la Neige, 38000 Grenoble, FranceLaboratory of Climatology, Department of Geography, SPHERES, University of Liège, Liège, BelgiumUniversité Grenoble Alpes, CNRS, Institut des Géosciences de l’Environnement, 38000 Grenoble, FranceUniversité Grenoble Alpes, Université de Toulouse, Météo-France, CNRS, CNRM, Centre d'Etudes de la Neige, 38000 Grenoble, France<p>In climate models, the snow albedo scheme generally calculates only a narrowband or broadband albedo, which leads to significant uncertainties. Here, we present the Versatile ALbedo calculation metHod based on spectrALLy fixed radiative vAriables (VALHALLA version 1.0) to optimize spectral snow albedo calculation. For this optimization, the energy absorbed by the snowpack is calculated by the spectral albedo model Two-streAm Radiative TransfEr in Snow (TARTES) and the spectral irradiance model Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART). This calculation takes into account the spectral characteristics of the incident radiation and the optical properties of the snow based on an analytical approximation of the radiative transfer of snow. For this method, 30 wavelengths, called tie points (TPs), and 16 reference irradiance profiles are calculated to incorporate the absorbed energy and the reference irradiance. The absorbed energy is then interpolated for each wavelength between two TPs with adequate kernel functions derived from radiative transfer theory for snow and the atmosphere. We show that the accuracy of the absorbed energy calculation primarily depends on the adaptation of the irradiance of the reference profile to that of the simulation (absolute difference <span class="inline-formula"><1</span> W m<span class="inline-formula"><sup>−2</sup></span> for broadband absorbed energy and absolute difference <span class="inline-formula"><0.005</span> for broadband albedo). In addition to the performance in terms of accuracy and calculation time, the method is adaptable to any atmospheric input (broadband, narrowband) and is easily adaptable for integration into a radiative scheme of a global or regional climate model.</p>https://gmd.copernicus.org/articles/14/7329/2021/gmd-14-7329-2021.pdf |
| spellingShingle | F. Veillon F. Veillon M. Dumont C. Amory C. Amory M. Fructus A versatile method for computing optimized snow albedo from spectrally fixed radiative variables: VALHALLA v1.0 Geoscientific Model Development |
| title | A versatile method for computing optimized snow albedo from spectrally fixed radiative variables: VALHALLA v1.0 |
| title_full | A versatile method for computing optimized snow albedo from spectrally fixed radiative variables: VALHALLA v1.0 |
| title_fullStr | A versatile method for computing optimized snow albedo from spectrally fixed radiative variables: VALHALLA v1.0 |
| title_full_unstemmed | A versatile method for computing optimized snow albedo from spectrally fixed radiative variables: VALHALLA v1.0 |
| title_short | A versatile method for computing optimized snow albedo from spectrally fixed radiative variables: VALHALLA v1.0 |
| title_sort | versatile method for computing optimized snow albedo from spectrally fixed radiative variables valhalla v1 0 |
| url | https://gmd.copernicus.org/articles/14/7329/2021/gmd-14-7329-2021.pdf |
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