Heavy Precipitation in the Alpine Region (HERA): Areal Rainfall Determination for Flood Warnings Through in-situ Measureme nts, Remote Sensing and Atmospheric Modelling

Summary.  Background and key results of the EU-funded project HERA are presented. The identification of the growing possibilities to use forecast precipitation fields as input for hydrological models is followed by a broad assessment of the state of the art regarding the determination of the atmospheric part of the hydrological cycle, with the geographical focus on the mountainous region of the Alps in the heart of Europe. This includes the construction of (north)Alpine radar composites for nine episodes; a first systematic cross-validation on a daily basis of four operational forecasting models with a trans-national gridded observat ional dataset; several detailed case studies involving research versions of operational forecast models and the latest advances in model resolution and microphysical parameterizations; new algorithms for Doppler radar retrievals over complex terrain; and synthetic modelling studies with governing parameters derived from the selected cases to investigate some basic processes in isolation. Finally, implications for proto-type applicatio ns of forecast areal precipitation fields in the hydrological modelling of mountainous catchments are given. Received April 14, 1999/Revised August 3, 1999