Cloud system-resolving simulations and a simple model of an idealized Walker cell

An idealized Walker cell with prescribed sea surface temperature is studied using both a two-dimensional cloud system-resolving model (CSRM) and a simple conceptual model. For simplicity, radiative cooling is prescribed in the CSRM. For the same sea surface temperature distribution, the Walker cell varies systematically, as the magnitudes of the radiative cooling or the strength of surface drag are varied, transitioning between a single-peak precipitation and a double-peak precipitation distribution. A simple model is constructed to interpret these behaviors.