HR: 1330h
AN: G23B-02    [Abstracts]
TI: GRACE Gravity and Airborne Surveys in the Arctic: How They Agree, Differ and Complement Each Other
AU: Childers, V A
EM: vicki@qur.nrl.navy.mil
AF: Naval Research Laboratory , Code 7421, 4555 Overlook Ave.SW,, Washington, DC, DC 20375 United States
AU: * McAdoo, D C
EM: Dave.McAdoo@noaa.gov
AF: NOAA Laboratory for Satellite Altimetry , 1335 East-West Highway E/RA31, Silver Spring, MD 20910 United States
AU: Marks, K M
EM: Karen.Marks@noaa.gov
AF: NOAA Laboratory for Satellite Altimetry , 1335 East-West Highway E/RA31, Silver Spring, MD 20910 United States
AU: Brozena, J M
EM: John.Brozena@nrl.navy.mil
AF: Naval Research Laboratory , Code 7421, 4555 Overlook Ave.SW,, Washington, DC, DC 20375 United States
AB: In the past dozen years large areas of the Arctic have been surveyed using accurate airborne gravity techniques for the most part by the Naval Research Laboratory (NRL). Precise NRL surveys conducted in the late 1990s include numerous long (>1500 km) lines extending from the Svalbard area over the pole to the Canada Basin. These surveys validate - rather well - the GRACE mean fields (e.g., the UTCSR GGM02S) inasmuch as the GRACE and aero-gravity here match each other in the waveband 350 to 3000 km. These late-90s NRL surveys are precise ( ~ 2mGal) and detailed as they were flown at low ( ~ 300 m) elevations. Now that the GRACE data have been validated, we can in turn use these data to evaluate the quality of earlier airborne data collected during times of poorer GPS positioning. In fact, differences between GRACE and low-pass filtered airborne and surface gravity can be used to identify areas where airborne surface gravity are likely be substantially in error. We show examples of such places over southeastern Greenland and the Canadian Archipelago. Ultimately, a high-accuracy Arctic gravity field and geoid can be produced by combining the long-wavelength component of GRACE gravity with the short-wavelength airborne and surface gravity. However, by first using the GRACE data to correct long-wavelength problems in the airborne and surface measurements, a better quality gravity field and geoid can be created. We show the corrected gravity field and its impact on the geoid.
DE: 1219 Local gravity anomalies and crustal structure
DE: 1243 Space geodetic surveys
SC: Geodesy [G]
MN: 2005 Joint Assembly