Impacto do realce de fluxo à superfície por rajadas de nuvens convectivas: experimentos com o modelo BRAMS.

Abstract

In this work a parameterization scheme for surface-flux enhancement due to gustiness associated with convective clouds is implemented in the BRAMS model. Several sensitivity experiments are conducted using some of the model’s options of convection parameterization. The period studied presents several precipitation-producing systems. The results showed a significant impact on the precipitation field. The impact is more pronounced in the ITCZ region, where the synoptic wind is weaker. The experiment using the Kuo scheme shows a negative correlation between flux enhancement and precipitation. However, the experiments with a mass-flux convective scheme show an increase in precipitation as a consequence of the flux enhancement at the surface. Finally, experiments with a weak nudging show a stronger impact. This suggests such a mechanism should be implemented in global models.