Mean Dynamic Topography and Geostrophic Surface Currents in the Fram Strait Derived from Geodetic Data

Abstract

Two mean dynamic topography (MDT) fields are determined in the Fram Strait between Svalbard and Greenland. New airborne gravity anomalies, older data, and two different mean sea surface (MSS) fields are combined using the least squares collocation (LSC) technique. The results are compared to an oceanographic MDT model and two synthetic MDT fields. The same main currents are seen in all fields. Additionally, smaller scale features are revealed in the new MDT fields. Geostrophic surface currents derived from the MDT models are compared to moorings and Lagrangian drifters. The agreement is desultory. The oceanographic data are an inadequate basis of comparison due to data gaps. Nevertheless, it is the only one available.

Keywords:

• Gravity
• altimetry
• dynamic topography
• geostrophic surface currents
• Fram Strait

Acknowledgements

Financial support from the Norwegian Research Council through the OCTAS project and a strategic institute program (ISP) is gratefully acknowledged. In this paper many of the computations were done with the GRAVSOFT-package (Tscherning et al. 1992). The new airborne gravity data were processed by Arne Olesen at Danish National Space Center (DNSC). K. Ghazavi and O. Omang are acknowledged for access to their unpublished MSSH fields and geoid models, respectively. F. Siegismund is acknowledged for providing velocity fields derived from drifters.

Notes

∗Now at the Norwegian Mapping and Cadastre Authority