Gravity measurements were carried out with a marine gravimeter of type Ultrasys Lacoste and Romberg, as on LOMROG I, mounted in the engine room close to the centre of mass of Oden (picture 1). The processed data yields gravity values with an accuracy and resolution that are dependent on the prevailing speed of Oden and ice conditions.

As a complement to the marine gravity data, gravity was measured on each bathymetric sounding station using an ice-dampened Lacoste & Romberg land gravimeter across the flanks of the Lomonosov Ridge (picture 2) and an additional 25 gravity readings were undertaken along Oden’s track. At 21 of these stations the thickness of the sea ice was measured. Supplementary data was collected using electromagnetic equipment that can measure the conductivity of the subsurface, where the ocean is more saline than the sea ice and therefore a better conductor. The conductivity measurement can be converted to sea ice thickness.

Oden again provided an excellent platform for marine gravity measurements. Recordings in the ice were superior to data from many other icebreakers or even submarines, in spite of the irregular navigation with frequent course and speed changes. The Ultrasys Lacoste Romberg gravimeter employed proved stable and reliable with only a small drift and the gravimetric data collected will be useful both in connection with the Danish UNCLOS project, as well as an important new data contribution to the Arctic Gravity Project.