Influence of Physical Parameterization Changes in the ALARO High Resolution NWP Model for Belgium on the CTM CHIMERE

Abstract

At the Royal Meteorological Institute of Belgium the chemical transport model (CTM) CHIMERE runs at a spatial resolution of 7 km. The CTM is first run on a coarse resolution of 50 km covering Western Europe. As a NWP input, the meteorological fields of ECMWF are consulted. The emission database is provided by EMEP. This model run is used as input for the boundary conditions for the coupled high resolution (7 km) chemical transport model run. This one-way nested coupling with the high resolution limited area NWP model ALARO (spatial resolution of 7 km) improved already significantly the modelling of ozone concentrations by improving the physical parameterization, i.e. cloud cover, surface temperature, surface sensible heat flux, surface latent heat flux and relative humidity fields. The model domain of ALARO covers Belgium and the Netherlands (680 × 680 km2). The emission database used as input for this high-resolution model is the TNO/GEMS emission database (Visschedijk AJH, Zandveld PYJ, Denier van der Gon HACA, High resolution gridded European database for the EU integrate project GEMS, TNO-report 2007-A-R0233/B, 2007). We will present the influence from the improved physical parameterizations of the NWP model on air quality model forecast performance for two different time periods. Also the influence on the implementation of a new surface scheme (SURFEX including The Town Energy Balance (TEB) scheme) in the NWP limited area model will be shown. © Springer Science+Business Media Dordrecht 2014.