A multi-method intercomparison approach for precipitation fields modelled by LAMs in the Alpine area: Two FORALPS case studies

Sharing knowledge and experience about NWP verification among forecasting centres, research institutions and environmental agencies in the Alpine area has been one of the main goals of the EU FORALPS project - INTERREG IIIB Alpine Space. In this framework, state-of-the-art verification techniques employed by project partners have been shared and applied to numerical simulations of selected case studies of rainfall events on the north-eastern Alpine area. In this work, a multi-method approach is presented. Simulations of two events with three limited area models (LAMs) are verified with traditional and more innovative techniques, including both traditional eyeball methods, categorical scores and skill scores, along with advanced object-oriented techniques such as the continuous rain area (CRA) analysis. Simulations of satellite observed fields (METEOSAT-7 Water Vapour channel) are also employed, to check qualitatively the impact of initialisation on the model error growth. Most importantly, it is shown how this multiplicity of perspective allows a deeper understanding of the results and facilitates their interpretation, thus suggesting that this multi-method approach should be followed in future works.