Ocean Circulation and Transport Between North Atlantic and the Arctic Sea with a focus on the importance of a high accuracy geoid model

The OCTAS project is a multidisciplinary approach to determine the mean dynamic sea surface topography (MDT) in the Fram Strait and adjacent seas. This will serve as input to ocean circulation and transport studies in the polar region. Improved determination of MDT will allow assessment of its impact on circulation studies and associated climate modeling. To achieve this objective high accuracy gravimetric geoid and mean sea surface models are required, and these will be derived as part of the project. New airborne gravity data has been obtained. All gravity data has been error screened and quality assured by removing dubious data and adjusting marine gravity data when necessary, in order to derive a regional high accuracy gravimetric geoid. Mean sea surfaces from satellite altimetry and mean dynamic topography from climatology and hydrography are under development. A preliminary assessment of these data sets have been made and techniques are being developed to optimally estimate the different quantities in an integrated approach.