Idealized studies of the ITCZ using cloud-resolving, parameterized, and superparameterized simulations

General circulation models have been known for many years to produce unobserved or unrealistic "double" intertropical convergence zones (ITCZs) that straddle the equator. In a theoretical framework, it remains unknown whether a double ITCZ should occur at all, and if so, whether this requires a fairly "flat" SST profile at the equator, ocean coupling, or both. This study employs models with explicit convection to study ITCZs over the oceans, their interactions with tropical waves, and the dependence of both on convective and mesoscale processes. The primary modeling tool is the Weather Research and Forecast (WRF) system, which has been augmented to run either as a high-resolution nested tropical channel or as a lower-resolution model with a cloud-resolving model used as a “superparameterization” for convection. In an effort to identify the causes of the double-ITCZ problem in global models, results from these simulations will be compared to each other and to simulations with standard cumulus parameterizations.