The Canadian Earth System Model version 5 (CanESM5.0.3)

• Published in: Geoscientific Model Development 2019-11, Vol.12 (11), p.4823-4873
• Main Authors: Swart, Neil C, Cole, Jason N. S, Kharin, Viatcheslav V, Lazare, Mike, Scinocca, John F, Gillett, Nathan P, Anstey, James, Arora, Vivek, Christian, James R, Hanna, Sarah, Jiao, Yanjun, Lee, Warren G, Majaess, Fouad, Saenko, Oleg A, Seiler, Christian, Seinen, Clint, Shao, Andrew, Sigmond, Michael, Solheim, Larry, von Salzen, Knut, Yang, Duo, Winter, Barbara
• Format: Article
• Language: English
• Subjects: Analysis; Atmospheric models; Carbon cycle; Carbon cycle models; Climate change; Climate models; Climate science; Climate sensitivity; Climate variability; Computer simulation; Control simulation; Control stability; Earth; Future climates; General circulation models; Global temperature changes; Intercomparison; Ocean models; Oceans; Optimization; Resolution; Sea ice; Sea ice models; Spectral resolution; Three dimensional models
• ISSN: 1991-9603; 1991-959X; 1991-962X; 1991-9603; 1991-962X
• DOI: 10.5194/gmd-12-4823-2019

The Canadian Earth System Model version 5 (CanESM5) is a global model developed to simulate historical climate change and variability, to make centennial-scale projections of future climate, and to produce initialized seasonal and decadal predictions. This paper describes the model components and their coupling, as well as various aspects of model development, including tuning, optimization, and a reproducibility strategy. We also document the stability of the model using a long control simulation, quantify the model's ability to reproduce large-scale features of the historical climate, and evaluate the response of the model to external forcing. CanESM5 is comprised of three-dimensional atmosphere (T63 spectral resolution equivalent roughly to 2.8∘) and ocean (nominally 1∘) general circulation models, a sea-ice model, a land surface scheme, and explicit land and ocean carbon cycle models. The model features relatively coarse resolution and high throughput, which facilitates the production of large ensembles. CanESM5 has a notably higher equilibrium climate sensitivity (5.6 K) than its predecessor, CanESM2 (3.7 K), which we briefly discuss, along with simulated changes over the historical period. CanESM5 simulations contribute to the Coupled Model Intercomparison Project phase 6 (CMIP6) and will be employed for climate science and service applications in Canada.