KMCM

KMCM (Kühlungsborn Mechanistic Circulation Model) is a so called Simple General Circulation Model (SGCM), describing atmospheric flow of dry air under physically idealized conditions. The basic numerical schemes are discretization in vertical direction according to Simmons & Burridge (1981), representation by spherical harmonics in horizontal direction (Machenhauer & Rasmussen, 1972) and semi-implicit time stepping (Asselin, 1972; Hoskins & Simmons, 1975). Realistic large-scale orography can be included due to the reference state reformulation of Simmons & Chen (1991). The thermal forcing of the model consists of temperature relaxation, prescribed tropical heat sources and self-induced heating in the middle latitudes. Orography and heating functions can independently be substituted by their zonal averages. KMCM includes a realistic boundary layer parameterization with the surface temperature being defined consistently with the thermal forcing. Horizontal diffusion is formulated consistently with elementary hydrodynamics (Becker, 2000). In this model version, no parameterization of inertia-gravity waves is used.