Coastal Tropical Convection in a Stochastic Modeling Framework

Recent research has suggested that the overall dependence of convection near coasts on large-scale atmospheric conditions is weaker than over the open ocean or inland areas. Because convection is often supported by meso-scale sea-breezes and the topography of coastal areas is not fully resolved in global numerical models tropical coastal convection remains poorly captured by them. We first develop a decision algorithm that solely depends on large-scale precursors and predicts the occurrence of sea-breeze conditions. The algorithm is then implemented into the UK Met Office's Unified Model to inform the models cumulus parametrization scheme about the presence of land-sea interaction and alter the occurrence of convection in the model. Offline tests of the new sea-breeze parametrization scheme with ERA-Interim data suggest that the developed method has potential to improve the representation of clouds and convection in global numerical weather forecasting and climate models.