Convective Adjustment

Abstract

The term convective adjustment describes any of several procedures used in numerical models to simulate the effects of dry and/or moist convection by adjusting the lapse rates of temperature and moisture to specified profiles within the local grid column. The origins of convective adjustment lie in simple concepts of local mixing within unstable layers. For example, most numerical models assume that dry superadiabatic lapse rates overturn spontaneously, mixing to a neutral lapse rate. The original form of the moist convective adjustment cumulus parameterization (Manabe et al. 1965) applied the same logic to conditionally unstable layers that become saturated in models. The physical properties of the clouds are entirely implicit. The characteristic of convective adjustment schemes that distinguishes them from other cumulus parameterizations is their direct specification of the adjusted vertical structure of the column without attempting to simulate the explicit convective processes.