Evaluation of SEVIRI retrieval of high ice water content environments with other satellite measurements (HAIC Deliverable 32.5)

A detailed evaluation of the SEVIRI CPP High IWC mask using one full year of DARDAR data is presented, using the methodologies reported in de Laat et al. [2016] and HAIC D32.2. In addition, a preliminary comparison with a MODIS-based High IWC mask is also discussed.
The performance of the High IWC mask is sensitive to the altitude of the High IWC, solar zenith angles and viewing zenith angles, as well as environmental conditions (small scale High IWC variability, size of the High IWC environments). Taking these sensitivities and environmental conditions into account, the POD is 90% or better, and under ideal conditions (high altitudes, large High IWC area), the POD can even be better than 99%.
The occurrence of High IWC shows clear spatial patterns, which could be useful in the future for aviation strategic planning purposes, while high IWC above 8 km altitude (approximately FL 27000) predominantly occurs in the tropics.
Verification of the High IWC mask from satellite instruments other than SEVIRI shows similar results, indicating that the CPP High IWC mask is a robust data product that can be applied to other satellite instruments measuring cloud properties similar to those measured by CPP.
Recommendations are provided for additional verification efforts, application of the CPP High IWC mask to other geostationary satellites for construction of a global near-real-time High IWC mask, and for a possible future implementation in aviation operations.