An f-plain Cloud-Resolving Radiative-Convective Equilibrium

A radiative-convective equilibrium (RCE) is often used as an idealization for the mean tropical climate. The results of rotating RCE simulations for a wide range of prescribed sea-surface temperatures (SSTs), from 21C to 36C, are presented. To simulate multiple coexisting tropical cyclones (TCs) over a relatively small 2300 x 2300 km2 domain with a 3 km horizontal grid spacing, the Coriolis parameter is artificially increased by about one order of magnitude over typical values in TC-active regions of the Tropics. The average number of TCs in the rotating RCE, which we nickname ‘‘TC World,'' monotonically decreases from 26 to 8 with increasing SST, while the TCs' size, intensity, and per-TC precipitation rate tend to increase with increasing SST. The average per-TC kinetic energy and precipitation rate approximately double for every 6C SST increase. The results are consistent with scaling laws in which TC diameters scale with the potential intensity ratio to the Coriolis parameter; however, it is shown the separation between cyclone centers appears to scale with the deformation radius. In particular, it is found that the number of TCs per unit area is inversely proportional to the saturation vapor pressure computed at SST. It is also found that the potential intensity scales as the cube root of the net radiative cooling of the atmosphere. The results show that the TC outflow temperature in the TC World, as defined as the height of the local maximum of the upper-troposphere cloud fraction, tends to remain relatively invariant with SST.