Retrieval of Cloud Height and Cloud Albedo from GOME-2 using the new ROCINN algorithm

Abstract

Precise cloud information is mandatory for the accurate retrieval of trace gas products. The ROCINN algorithm retrieves cloud-top height and cloud albedo from GOME-2 measurements in and around the oxygen A-band (~760nm) taking as input the cloud fraction computed with the OCRA algorithm. The operational version of ROCINN currently used for the generation of the O3M-SAF total column products treat clouds as reflecting surfaces. In this work we present the new generation of the retrieval algorithm ROCINN that treats clouds as scattering layers (CAL) instead of reflecting boundaries (CRB) and retrieves cloud-top height and optical thickness. Sensitive studies of the ROCINN-CAL algorithm to different observing and atmospheric parameters using synthetic spectra will be presented. Additionally, cloud properties from GOME-2 retrieved with the new ROCINN-CAL will be compared to the operational GOME-2 cloud products obtained with ROCINN-CRB. Finally, a comparison of GOME-2 cloud properties retrieved with ROCINN-CAL and cloud properties from the AVHRR sensor also flying on MetOp will be presented.