Abstract : 3P.4
Multi-model simulation of a convective situation in mountainous terrain

Jörg Trentmann, Christian Barthlott, Hans-Stefan Bauer, Christian Keil, Marc Salzmann, Mark Lawrence, Daniel Leuenberger, Heini Wernli, Volker Wulfmeyer
Institute for Atmospheric Physics, University Mainz

In mid-latitude mountainous regions, convective precipitation is the dominant form of summer precpitation. Forecasting convective precipitation remains a challenge for current state-of-the-art numerical weather prediction (NWP) models. Especially in mountainous regions small scale local flow systems can determine the timing and location of convection. Only very recently, the spatial resolution of NWP models has been increased to an extent that they start to explicitly resolve the processes associated with deep convection. The objective of this paper is to evaluate the performance of state-of-the-art NWP models under convective conditions in mountainous terrain in Central Europe.

As a first case study, we investigate the performance of three different models run by different groups for 12 July 2006. This day was characterized by weak large scale forcing over Europe and single cell convection occurred in the early afternoon over the black forest in South-West Germany. Model simulations are conducted using the operational weather forecast model COSMO LM, the MM5, and the WRF model. All models were used with an explicit description of deep convection, i.e., without the parameterization of deep convection. Besides the use of different models, the technical realization of the model simulation (e.g., model domain, initial and boundary conditions) differs among the groups, which leads to a further spread of the model results. The evaluation of the model simulations will lead to insights regarding the ability of the models to simulate the atmospheric conditioning under convective situations and the initiation of convection in mountainous regions.