The In-flight icing warning system ADWICE for European airspace – Current structure, recent improvements and verification results

The Advanced Diagnosis and Warning System for Aircraft Icing Environments (ADWICE) has been in development since 1998 in a collaboration between the German Aerospace Centre (DLR), Deutscher Wetterdienst (German Weather Service, DWD) and the Institute of Meteorology and Climatology of the Leibniz Universität Hannover (IMuK). ADWICE identifies atmospheric regions containing supercooled liquid water where aircraft icing can occur. Running operationally at DWD since 2002, ADWICE is used at the German Advisory Centres for Aviation (Luftfahrtberatungszentrale) to support pilots in route planning by warning of hazardous in-flight icing conditions. The model domain covers Europe and the Mediterranean coast of North Africa with a horizontal grid spacing of about 7 km and 30 vertical hybrid levels. The warning system consists of two algorithms. Based on output data of the operational numerical weather prediction model COSMO-EU (Consortium of Small-Scale Modelling – Europe), the Prognostic Icing Algorithm (PIA) allows the forecast of areas with an icing hazard. The Diagnostic Icing Algorithm (DIA) realises a fusion of forecast, observational and remote sensing data such as satellite data to describe the current icing hazard. Both algorithms create a three-dimensional icing product containing information about the likely icing scenario and its associated icing intensity. This paper describes the current structure of ADWICE, its output, as well as its diagnosis and forecast skill. For verification, the output of the two algorithms was compared with pilot observations over Europe. The results show satisfactory values for the probability of detection and the volume efficiency