Sensitivity of Convection Schemes and Microphysics in Mesoscale Simulations of Squall Line Observed During the AMMA Campaign Using the WRF Model

In this paper, a sensitivity study of convection schemes and cloud microphysics is performed using the Weather Research and Forecasting (WRF) model. It concerns the mesoscale simulation of the squall line observed during the African Monsoon Multidisciplinary Analysis campaign on September 22nd, 2006. Four convection schemes (Kain-Fritsch, Grell-Devenyi, Tietke and New Simplified Arakawa-Schubert) and five microphysics schemes (WRF Single-Moment 3-class (WSM3), WRF Single-Moment 5-class (WSM5), WRF Single-Moment 6-class (WSM6), Thompson and NSSL2-moment) are used. Each microphysics scheme is associated with a convection scheme, giving twenty combinations. The goal is to find the combination able to provide a realistic representation of the meteorological fields associated to the studied squall line, especially those of precipitation. The New Simplified Arakawa-Schubert convection scheme combined either with the WSM6 microphysics scheme, either with the WSM5 microphysics scheme or Thompson scheme was found to give a result closer to observation. The study also confirms that convection schemes have much more influence than microphysics on precipitation heights.