The 23rd Conference on Hurricanes and Tropical Meteorology

6D.6
SIMULATION OF A SQUALL LINE ASSOCIATED WITH AN AFRICAN EASTERLY WAVE; SENSITIVITY TO THE PARAMETERIZATION OF CONVECTION

J F. Gueremy, Meteo-France, Toulouse, France; and J. P. Ceron

The aim of this study is to investigate the sensitivity of the simulation of an intense convective system to several parameters of the mass flux convection scheme. This study is carried out in the frame of the West African Monsoon Project (EU Project).

A real case of squall line associated with an African easterly wave, which occurred the 21-08-1992 during the Hapex-Sahel experiment, has been chosen for this study. Different types of observations are available for this case, ranging from high resolution surface data in the square degree area of the experiment to radar and satellite data, together with the ECMWF analyses. Simulations has been carried out for 24 hours using the Meteo-France spectral limited area model Aladin at different horizontal resolution (of the order of 10 to 80 km), with the help of the ECMWF analyses as lateral boundary conditions.

Results will be shown from simulations done with modifications in several aspects of the convection scheme. Those modifications concern the closure assumption (moisture convergence versus CAPE), the cloud profile (one cloud is taken into account in this convection scheme), the inclusion of downdrafts, the convective momentum transport

The 23rd Conference on Hurricanes and Tropical Meteorology