Cloud resolving simulations of an idealized intertropical convergence zone

The parameterization of cumulus convection remains one of the primary limiting factors in our ability to accurately represent synpotic-scale features in the tropics that are driven by convective heating. An example is the structure of the Intertropical Convergence Zone (ITCZ), which has shown daunting sensitivity to both resolution and cumulus parameterization in numerous simulations using both real-earth and aquaplanet models. In this work, we use a regional model (WRF version 3.0.1) to simulate an idealized ITCZ in a tropical channel configuration with periodic boundary conditions in the zonal direction. The model has been adapted to allow for nesting that extends across the periodic interface, thus allowing for much higher resolution in the convecting regions. Simulations with low resolution and cumulus parameterization may be directly compared to cloud-resolving simulations without parameterization in the convection region (the ITCZ). In most cases, the simulations generate eastward propagating convectively coupled Kelvin waves. Some features of observed waves are explicitly reproduced in these simulations, such the cycle of shallow convection, deep convection, and then stratiform convection as the wave passes.