Brief description

KMCM 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 and 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 indep endently 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 hydro dynamics (Becker, 2000). Internal gravity waves are parameterized following Lindzen's theory of gravity wave saturation (Lindzen, 1981; Holton, 1982), but by employing a new formulation of the heating terms such as to ensure consistency with the energy conservation law and the theorems of Eliassen
and Palm (Becker and Schmitz, 2000b).