Impacto da convecção rasa em um modelo de mesoescala: sensibilidade aos parâmetros do esquema de parametrização.

Abstract

In this study, we investigate the impact of implementing a shallow cumulus parameterization scheme in the meso-scale model RAMS (Regional Atmospheric Modeling System), The model was run in its original configuration and in the new configuration containing the parameterization scheme. The model was integrated for a 48 h period starting on 00:00 UTC, 01 March 1986. The results show that implementing the shallow cumulus scheme in the model causes a significant impact in the thermodynamic profiles (temperature and moisture) of the atmosphere, along the model run. Furthermore, the convective precipitation increases substantially in the model's domain, as a result of the increased surface latent heat flux. Model sensitivities to the parameters of the scheme were tested through numerical experiments in which the total buoyancy and the cloud depth was modified (changing the entrainment rate. Results show that the model has a greater sensitivity to changes in the entrainment rate that produce shallower clouds, the sensitivity to changes that produces deeper clouds is low. In addition, we show that modifications in the total buoyancy are important because they can intensify or attenuate areas of warming and cooling near the clouds, changing atmospheric stability.