What was discovered by a team of US and Russian researchers, whose results were published on 12/6/2000?

AGP = Arctic Gravity Project

There is currently a great need to compile a uniform gravity grid of the Arctic region, for use in both geophysics/geology and geodesy/orbit determination. Recent advances in data collection technology, notably the advent of airborne gravimetry, the development of satellite altimetry over ice-covered regions, and availability of gravity data from scientific cruises with nuclear submarines, have meant that a large part of the Arctic is covered by substantial, accessible gravity field information.

The ArcGP will provide a detailed insight into the tectonics of the region, and allowing for the first time an accurate geoid model to be established. Recent presentations make it clear that monumental efforts have been made by Russia in mapping major parts of the gravity field of the Arctic Ocean, and make the formation of the ArcGP timely. The establishment of a freely available uniform gravity grid of the Arctic follows ongoing activities to develop an Arctic bathymetric map and database under the auspices of the International Hydrographic Office (IHO).

The Arctic Gravity Project (AGP) is a new international effort dedicated to the compilation of a public-domain gravity grid of the Arctic gravity field north of 64° N. The focus of the gravity grid will be the Arctic Ocean, Greenland, and the continental margins of the Asian and North American continents. The initiative for the project was taken after two international meetings in 1998 ("Airborne Gravity Measurements and the Polar Gravity Field", Greenland, June 1999, and the "International Conference on Arctic Margins (ICAM-III)" held in Celle, Germany, October 1999). The project proposal was inspired by presentations of Russian scientists, and by the success of the ongoing IHO project on Arctic Bathymetry. Ron McNabb, Canada, and B. Coakley, USA, were originally proposing a formal working group on gravity, for which the undersigned was subsequently proposed as chairman.

The primary interest is the compilation of state-of-the-art detailed free-air and Bouguer anomaly grids that will be made available to the general public in the year 2001. Additional tasks for the Arctic Gravity Project working group is to compare and calibrate different gravity sources, e.g. comparison of airborne, satellite, surface and submarine data, and the computation of an arctic-wide geoid model.

At the ICAM-III meeting National Geospatial-Intelligence Agency (NGA) offered the future ArcGP to assist in the compilation of the final gravity grid products, using the extensive personnel and computer resources available at NGA for this kind of work, and to release all data for the compilation of the grid product (the original data will not be made available, only the grids), including recent data acquired by the Naval Research Laboratory airborne gravity programmes plus other surface gravity data from its Point Gravity Anomaly file which contains over 35 million data values.

The target date for final 5Æ x 10Æ free-air and bouguer gravity grids to be released to BGI and the general public is December 2000 with preliminary grids released in 1999 to AGP Working Group Members. It is also planned to publish a CD-ROM.