Response of the CNRM-CM5 coupled model to an enhanced Greenland fresh water flux

Philippe Rogel (URA1875/CERFACS/CNRS, France)


Mathieu Hamon (Mercator-Ocean, Toulouse-France)

Event: 2014 Ocean Surface Topography Science Team Meeting

Session: Science Results from Satellite Altimetry: Regional and basin-scale processes and sea level rise

Presentation type: Type Poster

We investigate the transient response of the CNRM-CM5 coupled Ocean-Atmosphere model to a strong freshwater forcing around the Greenland coasts. We perturb a 50-year long ensemble of simulation with high-emission of Greenhouse gas (GHG) scenario (RCP8.5). The 5 members of the reference simulation are compared to 5 members of a similar simulation in which the freshwater perturbation is applied. We add 0,00275 Sv to the freshwater fluxes at the Ocean-Atmosphere interface representing 5 times the present estimated melting of the Greenland ice. We highlight that such a freshwater forcing has significant impacts only in the north Atlantic basin where a rapid increase of the sea level rise occurs in the first 30 years, followed by a stagnation period. In the others areas, we point out that the effects of the perturbation is not significant compared to the regional variability. We show relations between sea-level and the meridional overturning circulation (MOC), and attempt to characterize the mechanisms at stake in the CNRM-CM5 model. We thus focus on the effects of the freshwater forcing on the oceanic processes in the North Atlantic basin, especially on the temperature and salinity variability in the subpolar gyre.
Philippe Rogel