POLDER 2 - SCENE ALBEDO
SCENE ALBEDO
The spectral albedos (or hemispherical reflectances) are derived from POLDER measurements at 443 nm, 670 nm and 865 nm. The short wave albedo is then deduced from them. Finally the monthly average reflected flux is estimated for Earth Radiation Budget studies.
A short description is given here.
A more complete description can be downloaded from the "ERB, WV & clouds" algorithm documents for POLDER-2. If there are further questions regarding the spectral and shortwave albedo derivation, please contact Pr. J.C. Buriez (at LOA). For questions regarding the monthly reflected flux, please contact Dr. M. Viollier (viollier@lmd.polytechnique.fr).
See below the main parameters related to scene albedo that appear in the level-2 POLDER "ERB, WV & clouds" product.
| Avis | Mean albedo at 670 nm over land and 865 nm over ocean, result from an averaging over pixels and a weighting over directions. Click to view image Note that the mean "directional" albedo is also furnished for each viewing direction |
| RSD(Avis) | Relative Spatial standard Deviation of the albedos derived by pixel and by direction at 670/865 nm |
| RAD(Avis) | Relative Angular standard Deviation of the albedos derived by pixel and by direction at 670/865 nm |
| QAvis | Quality index related to the ratio between the relative angular deviation RAD(Avis) and that derived under the Lambertian hypothesis. It ranges from 0 (default) to 1 (ideal case). Click to view image |
| A*vis | Mean of the albedos calculated under the assumption of an homogeneous scene at 670/865 nm |
| RAD(A*vis) | Relative Angular standard Deviation of the albedos at 670/865 nm calculated under the assumption of an homogeneous scene |
| Asw | Shortwave albedo derived from the 443, 670 and 865 nm albedos. Click to view image Note that this parameter is also furnished for each viewing direction |
See below the main parameters related to scene albedo that appear in the level-3 POLDER "ERB, WV & clouds" product.
| M(Avis) | Monthly mean of the instantaneous albedo at 670 nm over land and 865 nm over ocean. Click to view image |
| TD(Avis) | Temporal standard Deviation of the instantaneous albedo at 670/865 nm |
| M(Avis)clear | Monthly mean of the instantaneous albedo at 670/865 nm when the superpixel is declared clear. Click to view image |
| TD(Avis)clear | Temporal standard Deviation of the instantaneous albedo at 670/865 nm when the superpixel is declared clear |
| M(Asw) | Monthly mean of the instantaneous shortwave albedos. Click to view image |
| TD(Asw) | Temporal standard Deviation of the instantaneous shortwave albedo |
| M(Asw)clear | Monthly mean of the instantaneous shortwave albedo when the superpixel is declared clear. Click to view image |
| TD(Asw)clear | Temporal standard Deviation of the instantaneous shortwave albedo when the superpixel is declared clear |
| M(Finc) | Monthly average shortwave incident flux (expressed in W/m²). Click to view image |
| M(Frefl) | Monthly average shortwave reflected flux (expressed in W/m²) |
| M(Frefl)clear | Monthly average clear-sky shortwave reflected flux (expressed in W/m²). Click to view image |
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