A single column model with parameterized large-scale dynamics is used to; better understand the response of steady-state tropical precipitation to; relative sea surface temperature under various representations of; radiation, convection, and circulation. The large-scale dynamics are; parametrized via the weak temperature gradient (WTG), damped gravity; wave (DGW), and spectral weak temperature gradient (Spectral WTG) method; in NCAR’s Single Column Atmosphere Model (SCAM6). Radiative cooling is; either specified or interactive, and the convective parameterization is; run using two different values of a parameter that controls the degree; of convective inhibition. Results are interpreted in the context of the; Global Atmospheric System Studies (GASS) Intercomparison (Daleu et al.; 2016). Using the settings given in Daleu et al. (2016), SCAM6 under the; WTG and DGW methods produces erratic results, suggestive of numerical; instability. However, when key parameters are changed to weaken the; strength with which the circulation acts to eliminate tropospheric; temperature variations, SCAM6 performs comparably to single column; models in the GASS Intercomparison. The Spectral WTG method is less; sensitive to changes in convection and radiation than are the other two; methods, performing at least qualitatively similarly across all; configurations considered. Under all three methods, circulation; strength, represented in 1D by grid-scale vertical velocity, is; decreased when barriers to convection are reduced. This effect is most; extreme under specified radiative cooling, and is shown to come from; increased static stability in the column’s reference; radiative-convective equilibrium profile. This argument can be extended; to interactive radiation cases as well, though perhaps less; conclusively.
