Operational cloud products from GOME-2 and perspectives for Sentinel-5P and Sentinel-4

Kurzfassung

Precise knowledge of cloud properties is an important ingredient for an accurate trace gas retrieval using satellite missions focused on atmospheric composition. Such missions include the operational GOME-2 instruments on-board MetOp-A/B/C, the soon-to-be-launched TROPOMI instrument on Sentinel-5P and the upcoming UVN/Sentinel-4 instruments on MTG-S. The OCRA/ROCINN algorithms are being used for the retrieval of cloud properties from GOME-2 in the framework of the O3M-SAF. The ROCINN algorithm retrieves cloud top height and cloud optical thickness (cloud albedo) from NIR measurements in and around the oxygen A-band taking as input the cloud fraction computed with the OCRA algorithm which is based on a broad-band UV/VIS/NIR color space approach. In this work we first present the latest algorithm developments for treating clouds as scattering layers and compare the GOME-2 results with the currently operational products that model clouds as a simple Lambertian surface. Finally we describe in detail the new developments of the OCRA/ROCINN algorithms that will be used for generating the operational products of the polar orbiting TROPOMI instrument on Sentinel-5P and to the geostationary UVN/Sentinel-4 instruments on MTG-S.