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

• Published in: Geoscientific Model Development
• Main Authors: Blaker, Adam T., Joshi, Manoj, Sinha, Bablu, Stevens, David P., Smith, Robin S., Hirschi, Joël J.-M.
• Format: Text
• Language: English
• Published: 2021
• Subjects: Moma; Sea ice
• Online Access: https://doi.org/10.5194/gmd-14-275-2021; https://gmd.copernicus.org/articles/14/275/2021/

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