Retrieval of high IWC from MSG-SEVIRI: first algorithm version (HAIC D32.1)

This report describes the first version of an algorithm for the detection of clouds with high ice water content (high IWC) from geostationary passive visible/infrared satellite observations. The theoretical basis, practical implementation, inputs and outputs as well as limitations are discussed. The algorithm is tailored to the Spinning Enhanced Visible and Infrared Imager (SEVIRI) instrument on board the Meteosat Second Generation (MSG) satellites. In a first step, a range of cloud properties is retrieved, including a cloud mask and thermodynamic phase discrimination, cloud-top height/temperature, cloud optical thickness, cloud water path, and particle effective radius. From these cloud properties a high IWC mask is then derived by using an Airbus-provided in-service event database as a reference. Due to a lack of verification events, it has not yet been possible to validate the high IWC mask. Future work will focus on the use of active (radar/lidar) satellite observations to improve and characterize the high IWC mask. Observations collected during previous Airbus field campaigns (e.g., Cayenne 2010) and the upcoming 2015 and 2016 HAIC campaigns will be used to validate the high IWC algorithm.