Inverse Estimate of the North Atlantic Circulation: Influence of the fine resolution GOCINA dynamic topography

The circulation in the North Atlantic subpolar gyre and the NordicSeas has been improved by assimilating the GOCINA altimetry into aninverse finite-element ocean circulation model. The inverse modelseeks for a density field which is close to the density data and hasa large-scale ocean circulation with a surface elevation which isclose to the GOCINA altimetry. Two model experiments are reporteddiffering by the use of an additional information on the deep oceancirculation (deep pressure gradients). This information is shown to becrucial in obtaining a realistic solution. Without it the inversesolution approaches the altimetry data by mostly developing abarotropic response with very small changes happening to the stericheight.