CONVECTION PARAMETERIZATION DIAGNOSIS IN THE ARPEGE/ALADIN MODEL USING ITS 1D VERSION FOR THE TOGA-COARE SQUALL LINE

摘要

The one-dimensional version of the numerical weather prediction ARPEGE/ ALADIN model was used for the evaluation of the deep convection parameterization scheme. The evolution of the squall line of 1993 February 22, observed during the TOGA-COARE experimental campaign, was simulated with the 1D model. The results were compared with the output of the resolving cloud model of Redelsperger and Sommeria (1986) and some deficiencies of the convection scheme, like an insufficient cloud vertical development, were found. The 1D model was also used to assess the impact of the introduction of convective downdraft parameterization and the pressure gradient term for the wind parameterization. A new formulation of the entrainment and detrainment rate together with a different way to compute the saturated adiabat was tested too. The analysis of the upward and downward mass flux, of the enthalpy and humidity budgets and the amounts of precipitation showed that the convection parameterization scheme could be improved by these modifications.