REPORT ON THE 2ND INTERNATIONAL WORKSHOP ON AIRBORNE GRAVIMETRY AND POLAR GRAVITY

Field, Svalbard, Norway, August 7, 1999.

Twenty participants from six countries gathered to an informal workshop on the Arctic gravity field, held at UNIS (University of Svalbard), Longyearbyen, Norway. The workshop was called at short notice to take advantage of several airborne gravity survey activities taking place at the same time from this high-Arctic location. The meeting was called to follow up a similar workshop held in Kangerlussuaq, Greenland, June 2-4, 1998. The workshop was sponsored by IAG section III. 

The workshop was organized by KMS (National Survey and Cadastre, Denmark) and University of Bergen. R. Forsberg, KMS initiated the workshop with a presentation on the Arctic Gravity Project, an international effort to compile a gravity grid of the Arctic region, a.o. to support the planned gravity field satellite missions. The Arctic Ocean is currently the object of intense gravity survey activities from both aircraft, submarines and icebreakers, and additionally the relaxation of historical tensions in the region have meant that comprehensive Russian data are now being presented also to western researchers. Sergei Maschenkov (VNIIO, Russia) gave an overview of results of the intensive Russian program by the presentation Arctic Gravity and Magnetic Compilation, in part carried out within a US/Russian bilateral coopeation. Most of the Arctic is covered with gravity observations, with many surveys carried out from numerous ice camps of the former Soviet Union. John Brozena (Naval Research Lab., USA) gave an overview talk of current US airborne activities in the Arctic. Since 1992 major parts of the western and central Arctic basins have been covered by long-range airborne gravimetry, in a program sponsored by NIMA. The data have provided significant new insight into the major tectonic elements of the Arctic Ocean. More technical talks included presentations by V. Childers (NRL) and A. V.Olesen (KMS) on details of aerogravity measurements and processing, and by K. Keller (KMS) and B. Nelson (DRE, Canada) on hardware setup for aerogravity and magnetic measurement systems. The later paper illustrated the high accuracy of modern magnetometer systems (.05 nT), as well as gave the point that magnetic measurements should referably always be made alongside aerogravity in such operationally difficult areas like the Arctic.

Regional project talks included presentation on German icebreaker and aerogeophysical activities in the Fram Strait region by U. Meyer (AWI, Germany), on ongoing KMS survey activities around Greenland (A. Olesen), Norwegian aerogravity activities in Greenland (D. Solheim/SK, A. Gidskehaug/UiB), and on Russian aerogravity activities around Frans Josef Land carried out in recent years. The different projects, based on many different kinds of aircraft (smaller Twin-Otters or Do-228s, or long-range P-3s or IL-38s) shows that aerogravity has now become an operational tool, although there still is room for much research and development on both improving gravity sensor performance as well as improving accuracy of long-range kinematic GPS.

Rene Forsberg

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