Abstract
Abstract. The Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP) aims to investigate the spread in simulations of sea-level and ocean climate change in response to CO2 forcing by atmosphere–ocean general circulation models (AOGCMs). It is particularly motivated by the uncertainties in projections of ocean heat uptake, global-mean sea-level rise due to thermal expansion and the geographical patterns of sea-level change due to ocean density and circulation change. FAFMIP has three tier-1 experiments, in which prescribed surface flux perturbations of momentum, heat and freshwater respectively are applied to the ocean in separate AOGCM simulations. All other conditions are as in the pre-industrial control. The prescribed fields are typical of pattern and magnitude of changes in these fluxes projected by AOGCMs for doubled CO2 concentration. Five groups have tested the experimental design with existing AOGCMs. Their results show diversity in the pattern and magnitude of changes, with some common qualitative features. Heat and water flux perturbation cause the dipole in sea-level change in the North Atlantic, while momentum and heat flux perturbation cause the gradient across the Antarctic Circumpolar Current. The Atlantic meridional overturning circulation (AMOC) declines in response to the heat flux perturbation, and there is a strong positive feedback on this effect due to the consequent cooling of sea-surface temperature in the North Atlantic, which enhances the local heat input to the ocean. The momentum and water flux perturbations do not substantially affect the AMOC. Heat is taken up largely as a passive tracer in the Southern Ocean, which is the region of greatest heat input, while the weakening of the AMOC causes redistribution of heat towards lower latitudes. Future analysis of these and other phenomena with the wider range of CMIP6 FAFMIP AOGCMs will benefit from new diagnostics of temperature and salinity tendencies, which will enable investigation of the model spread in behaviour in terms of physical processes as formulated in the models.
Highlights
Atmosphere–ocean general circulation models (AOGCMs) are widely used for projections of future sea-level change (e.g. Church et al, 2013; Slangen et al, 2014)
On the basis of AOGCM results contributed to the Coupled Model Intercomparison Project Phase 5 (CMIP5), global-mean sea-level rise (GMSLR) of 0.32–0.63 m (5–95 %, median 0.47 m) is projected by 2081–2100 under the mid-range RCP4.5 scenario considered in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) (Yin, 2012; Church et al, 2013)
The purpose of the Flux-Anomaly-Forced Model Intercomparison Project is to analyse the simulated response of the ocean to changes in surface fluxes resulting from CO2 forcing in AOGCMs
Summary
Atmosphere–ocean general circulation models (AOGCMs) are widely used for projections of future sea-level change (e.g. Church et al, 2013; Slangen et al, 2014). Atmosphere–ocean general circulation models (AOGCMs) are widely used for projections of future sea-level change On the basis of AOGCM results contributed to the Coupled Model Intercomparison Project Phase 5 (CMIP5), global-mean sea-level rise (GMSLR) of 0.32–0.63 m (5–95 %, median 0.47 m) is projected by 2081–2100 under the mid-range RCP4.5 scenario considered in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) (Yin, 2012; Church et al, 2013). Other contributions to GMSLR are due mostly to loss of land ice. Glaciers worldwide give 15–40 % of the total. The median projected contributions from the Greenland and Antarctic ice sheets are smaller, the latter is the largest source of uncertainty
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
