Similarity Among Atmospheric Thermal Stratifications Over Elevated Surfaces Under Radiative‐Convective Equilibrium

Abstract

AbstractAn air column under radiative‐convective equilibrium is studied here to understand equilibrium climate over different surface elevations. Cloud‐resolving model (CRM) simulations show that atmospheric thermal stratifications exhibit similar structures when expressed in sigma coordinates over varying surface elevations under radiative‐convective equilibrium. A zero‐buoyancy plume model that reproduces CRM results is used to interpret related processes. As surface pressure decreases, decreased pressure on a certain σ level leads to decreases of moist adiabatic temperature lapse rate, which largely cancel the increases of moist adiabatic lapse rate by temperature decreases. Meanwhile, the invariance of convective entrainment/detrainment rates keeps the deviation of environmental temperature lapse rate from moist adiabat approximately invariant, result in similar thermal stratifications under varying surface pressures. A comparison of thermodynamic profiles over the Tibetan Plateau with those over plains in reanalysis confirms the similarity found in CRM simulations. This similarity provides a useful simplification for representing the effects of convection.