Understanding of convective organization over the west Pacific equatorial zone is not a simple task, as no clear and intense large scale instabilities able to organize MCSs, are identified. Most of the time wind shears are weak to allow the convection initiation and organization. Among possible processes contributing to organize convective activity, we focused on gravity waves and density currents.
The current stage of our research is to examine the above questions owing to the use of nested simulations to cover a wide range of scales for a real case study of TOGA-COARE (11-12 december 1992) corresponding to a fast-moving squall line apparently generated after the collapsing stage of a previous MCS. The mechanisms of convection initialization though gravity waves and a density current are investigated throught the use of adequate diagnostics.