In low-mountain regions, the relevant processes leading to convective precipitation are still hardly understood. This is especially unsatisfactory as many severe weather events are related to convective precipitation in orographically-complex terrain. The Convective and Orographically-Induced Precipitation Study (COPS, www.uni-hohenheim.de/spp-iop) is an international field campaign planned for summer 2007 in Southern-Western Germany and North-Eastern France to tackle this problem. COPS is part of the German Priority Program "Praecipitationis Quantitativae Predictio" (PQP, http://www.meteo.uni-bonn.de/projekte/SPPMeteo/) and has been endorsed as World Weather Research Program (WWRP) Research and Development Project. During COPS a large suite of state-of-the-art remote sensing systems, ground-based and airborne, partly scanning and employed for the first time, will be combined with in-situ instruments. The measurement strategies involve state-of-the-art lidar systems as key instruments to provide high resolution data of atmospheric humidity, temperature, wind, and aerosols in clear-air, i.e., before the initiation of convection.

The overarching objective of COPS which is to identify the physical and chemical processes responsible for the deficiencies in quantitative precipitation forecast (QPF) over low-mountain regions and to improve their model representation. An important technique to achieve this goal is the assimilation of additional data, e.g., from lidar systems. Data assimilation allows too separate models errors due to errors in the initial fields and errors in the model parameterizations. Furthermore, re-analyses testing the assimilation of different data, will allow to investigate the sensitivity of the models. COPS builds on a series of previous international measurement campaigns focusing on quantitative precipitation forecast like the Mesoscale Alpine Program (MAP), 1999, the International H2O Project (IHOP_2002), 2002, and the Convective Storm Initiation Project (CSIP), 2005.

In July 2006, a pre-campaign called PRINCE (PRediction, Identification and trackiNg of Convective cElls) was conducted in the COPS region. Results of this campaign will be presented and an outlook on COPS will be given.