www.atmos-meas-tech-discuss.net/5/691/2012/ doi:10.5194/amtd-5-691-2012 © Author(s) 2012. This work is distributed under the Creative Commons Attribution 3.0 License. Desert dust satellite retrieval intercomparison 1Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, University of Oxford, Oxford, UK 2Space Science and Technology Department, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, UK 3Science Systems and Applications, Maryland, USA 4Laboratoire d'Océanographie de Villefranche (LOV), Centre National de la Recherche Scientifique (CNRS) and Université Pierre et Marie Curie, Paris 06, Villefranche-sur-Mer, France 5Geography Department, College of Science, Swansea University, UK 6Royal Netherlands Meteorological Institute (KNMI), The Netherlands 7Imperial College, London, UK 8University of Maryland Baltimore County, USA 9LOA, Université Lille-1, France 10Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA 11NASA Goddard Space Flight Center, Greenbelt, Maryland, USA *now at: Science, Applications and Future Technologies Department, ESA/ESTEC, The Netherlands Abstract. This work provides a comparison of satellite retrievals of Saharan desert dust aerosol optical depth (AOD) during a strong dust event through March 2006. In this event, a large dust plume was transported over desert, vegetated, and ocean surfaces. The aim is to identify and understand the differences between current algorithms, and hence improve future retrieval algorithms. The satellite instruments considered are AATSR, AIRS, MERIS, MISR, MODIS, OMI, POLDER, and SEVIRI. An interesting aspect is that the different algorithms make use of different instrument characteristics to obtain retrievals over bright surfaces. These include multi-angle approaches (MISR, AATSR), polarisation measurements (POLDER), single-view approaches using solar wavelengths (OMI, MODIS), and the thermal infrared spectral region (SEVIRI, AIRS). Differences between instruments, together with the comparison of different retrieval algorithms applied to measurements from the same instrument, provide a unique insight into the performance and characteristics of the various techniques employed. As well as the intercomparison between different satellite products, the AODs have also been compared to co-located AERONET data. Despite the fact that the agreement between satellite and AERONET AODs is reasonably good for all of the datasets, there are significant differences between them when compared to each other, especially over land. These differences are partially due to differences in the algorithms, such as assumptions about aerosol model and surface properties. However, in this comparison of spatially and temporally averaged data, at least as significant as these differences are sampling issues related to the actual footprint of each instrument on the heterogeneous aerosol field, cloud identification and the quality control flags of each dataset. Discussion Paper (PDF, 8479 KB) Interactive Discussion (Final Response, 3 Comments) Manuscript under review for AMT Citation: Carboni, E., Thomas, G. E., Sayer, A. M., Siddans, R., Poulsen, C. A., Grainger, R. G., Ahn, C., Antoine, D., Bevan, S., Braak, R., Brindley, H., DeSouza-Machado, S., Deuzé, J. L., Diner, D., Ducos, F., Grey, W., Hsu, C., Kalashnikova, O. V., Kahn, R., North, P. R. J., Salustro, C., Smith, A., Tanré, D., Torres, O., and Veihelmann, B.: Desert dust satellite retrieval intercomparison, Atmos. Meas. Tech. Discuss., 5, 691-746, doi:10.5194/amtd-5-691-2012, 2012. Bibtex EndNote Reference Manager XML |
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