Preliminary validation results of the OMI O2-O2 cloud product

Cloud correction is an important step in the retrieval process of trace gases from OMI spectra. There are two OMI cloud algorithms: one is based on the O2-O2 absorption band near 477 nm and the other is based on the filling-in of Fraunhofer lines by Raman scattering. Both retrieve an effective cloud fraction and cloud height. Verification and validation of these cloud products are relevant to the validation of the trace gas retrievals from OMI.

Since clouds are highly variable, a statistical approach is a logical way forward in this verification and validation process. The spatial and temporal consistency of the OMI O2-O2 cloud product is investigated using one year of data. This is mainly a verification of the retrieval algorithm. A comparison with external sources was performed. A first qualitative validation of the effective cloud fraction from OMI using MODIS/Aqua data shows good agreement. In this presentation a quantitative comparison between the cloud products of the two instruments will be shown.