Explicit Simulations of the Intertropical Convergence Zone

Abstract

Abstract The intertropical convergence zone (ITCZ) is one of the most important components of the global circulation. In order to understand the dynamical processes that regulate its formation, latitudinal preference, and structure, explicit two-dimensional numerical modeling of convection on an equatorial beta plane was conducted with a nonhydrostatic cloud-system-resolving model. The model was forced by energy fluxes associated with constant sea surface temperature (SST) and by horizontally homogeneous radiative cooling. Two distinct patterns were identified for the spatial distribution of convective activity in the Tropics. The first was characteristic of enhanced off-equator convection, namely, a double ITCZ-like morphology (one more salient than the other) straddling the equator during the early period of the integration. The second featured enhanced equatorial convection, namely, a single ITCZ-like morphology on the equator during the later quasi-equilibrium period. Diagnostic analysis and two addit...