ATSR Aerosol_cci ORAC
 |
 |
ORAC is one of the three ATSR-2/AATSR ECV products being produced by ESA Aerosol_cci project. The ORAC retrieval is an optimal estimation scheme, which makes use of the dual-view measurements from the ATSR instruments to provide aerosol optical depth, effective radius and surface reflectance at 0.55, 0.67, 0.87 and 1.6 μm. The dataset aims to provide a long-term, consistent record of global AOD for climate studies.
Example results (mean AOD for 2008)
| Satellite | ERS-2 (ESA), ENVISAT (ESA) |
| Instrument(s) | ATSR-2, AATSR |
| Algorithm PI | Gareth Thomas (STFC RAL Space) |
| Contact Details | gareth.thomas[at]stfc.ac.uk |
| Parameter(s) |
AOD at 0.55, 0.67, 0.87 and 1.6 μm, Ångström exponent, effective radius*, dust-, absorbing- and fine-mode-AOD at 0.55 μm*. Spectral surface albedo* at 0.55, 0.67, 0.87 and 1.6 μm. Limited aerosol type information (best fit model). (Parameters marked with * are experimental, and unvalidated) |
| Aerosol algorithm | ORAC dual-view |
| Cloud screening |
ESA Cloud Flag (ocean) / Stevens Cloud Flag (land) + additional algorithm specific tests. |
| Aerosol model | Aerosol_cci common aerosol components (de Leeuw et al., 2013) |
| Retrieval assumptions |
Ocean BRDF constrained by sea surface reflectance model driven by ECMWF 10 m wind fields |
| Retrieval limitations | Retrieval over land becomes poorly constrained at high optical depths, due to limited sensitivity to the surface |
| Spatial, temporal coverage | 1995-2012, global (2000/2008 test data available only as of Jan 2015) |
| Spatial, temporal resolution | 10 km – 1×1°. 512 km swath width. 16 day repeat cycle |
| Operations status | reprocessing |
| Validation status | Intercomparison with ground-based, airborne and other satellite data |
| Quality control | Uncertainty handling by optimal estimation. Product also contains quality flag (high/low confidence) |
| last algorithm version | v02.02 (12/2013) |
| last validation | 12/2013 |
| Algorithm description | Product format description |
| Version explanation | Validation summary |
| Publications |
| Product data access |
| Image / quicklook data access |