Interaction between SST and Convection in an Aquaplanet in Radiative Convective Equilibrium

Abstract:

In an aquaplanet in tropical radiative convective equilibrium, using interactive SST produces an inter-annual oscillation between a disaggregated state with a more uniform distribution of convection and SST and an aggregated state with convection concentrated over a small warm pool and subsidence over the larger cold pool. Adding a constant asymmetrical, net zero heat flux at the surface both fixes the location of the warm and cold pools and increases the speed of the oscillation. This heat flux increases the SST contrast between the warm and cold SSTs primarily through cooling the coldest SSTs. By increasing the circulation and atmospheric energy transport, the temperature of the warm pool is constrained and the global mean SST decreases. While the evaporative cooling at the surface increases everywhere, the low cloud fraction in the subsiding region decreases, despite increased stability.