FORTE 2.0: a fast, parallel and flexible coupled climate model

Abstract. FORTE 2.0 is an intermediate-resolution coupled atmosphere–ocean general circulation model (AOGCM) consisting of the Intermediate General Circulation Model 4 (IGCM4), a T42 spectral atmosphere with 35σ layers, to Modular Ocean – Array (MOMA), 2∘ × ocean 15 z-layer depth levels. Sea ice represented by simple flux barrier. Both and components are coded in Fortran. It capable producing stable climate for long integrations without need adjustments. One flexibility afforded IGCM4 ability configure either layers (troposphere stratosphere) or 20σ only). This enables experimental designs exploring roles troposphere stratosphere, faster integration layer configuration longer duration studies on modest hardware. A description given, followed analysis two 2000-year control integrations, one using configuration.