Forecasting Geopotential Trends in Southern Greenland

Abstract : During the summer seasons of 1991 and 1992, the Naval Research Laboratory (NRL) and the Naval Oceanographic Office in collaboration with researchers from the National Oceanic and Atmospheric Administration and the National Survey and Cadastre of Denmark will perform a detailed airborne survey of Greenland to map gravity, magnetics, and the topography of the entire island. During the first summer campaign, southern Greenland, below 70 N, will be surveyed with the NRL P-3 Orion aircraft equipped with LaCoste-Romberg and Bell gravimeters, radar and laser altimeters, Global Positioning System (GPS) receivers, and a proton-precession magnetometer. After processing of the GPS data to remove radial accelerations of the aircraft, it is anticipated that the gravity field will be recovered with an rms accuracy of 2 mgal for half-degree means. Along-track wavelength resolution should be on the order of 25-40 km. Because of the sparse distribution of gravity data within Greeland, the current mean anomaly field, primarily based on prediction, fails to replicate trends in the observed geopotential field. To better forecast trends, a project was initiated at the Naval Surface Warfare Center (NAVSWC) to collect and exploit higher resolution and more complete geophysical data sources.