PLASIM-GENIE v1.0: A new intermediate complexity AOGCM

• Published in: Geoscientific Model Development
• Main Authors: Holden, P., Edwards, N., Fraedrich, K., Kirk, E., Lunkeit, F., Zhu , X.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Sea ice
• Online Access: http://hdl.handle.net/11858/00-001M-0000-002B-8680-3; http://hdl.handle.net/11858/00-001M-0000-002B-868C-B

We describe the development, tuning and climate of Planet Simulator (PLASIM)-Grid-ENabled Integrated Earth system model (GENIE), a new intermediate complexity Atmosphere-Ocean General Circulation Model (AOGCM), built by coupling the Planet Simulator to the ocean, sea-ice and land-surface components of the GENIE Earth system model. PLASIM-GENIE supersedes GENIE-2, a coupling of GENIE to the Reading Intermediate General Circulation Model (IGCM). The primitive-equation atmosphere includes chaotic, three-dimensional (3-D) motion and interactive radiation and clouds, and dominates the computational load compared to the relatively simpler frictionalgeostrophic ocean, which neglects momentum advection. The model is most appropriate for long-timescale or large ensemble studies where numerical efficiency is prioritised, but lack of data necessitates an internally consistent, coupled calculation of both oceanic and atmospheric fields. A 1000-year simulation with PLASIM-GENIE requires approximately 2 weeks on a single node of a 2.1 GHz AMD 6172 CPU. We demonstrate the tractability of PLASIM-GENIE ensembles by deriving a subjective tuning of the model with a 50-member ensemble of 1000-year simulations. The simulated climate is presented considering (i) global fields of seasonal surface air temperature, precipitation, wind, solar and thermal radiation, with comparisons to reanalysis data; (ii) vegetation carbon, soil moisture and aridity index; and (iii) sea surface temperature, salinity and ocean circulation. Considering its resolution, PLASIM-GENIE reproduces the main features of the climate system well and demonstrates usefulness for a wide range of applications. © 2016 Author(s).