Aerogravity in Antarctica - a multi-instrument, multi-platform comparison of capabilities
Abstract
Major aerogravity surveys undertaken over the Antarctic and Greenland ice sheets over the last decade allow unique comparison between multiple instruments and survey platforms. The NSF ROSETTA-Ice project, NASA Operation IceBridge and NSF-NERC combined aerogeophysical survey of Thwaites Glacier have used different combinations of instruments on different survey platforms over some common survey lines. Over the Ross Ice Shelf, the ample cargo space in the LC-130 for IcePod flights with the ROSETTA-Ice project allowed installation of a suite of four gravimeters on a single platform, including an iMAR INAT, an iMAR DGU, a DgS AT1A, and ZLS, flown side-by side for over 25,000 km. In addition to these ROSETTA-Ice gravimeters, the survey overflew pre-existing survey lines occupied by Operation IceBridge with the SGL AIRGrav meter in 2013. Here we compare performance of these systems, and explore statistical and signal processing methods of combining meter outputs to provide robust measurements of the gravity field under a wide range of survey environments. We identify the ideal range of possible instrument suites for different platforms, survey environments, and project scope and resources.
We present a side-by-side comparison of gravity instruments flown along the shared OIB-ROSETTA baseline, as well as examples of data from more active flight survey environments. We compare several ways of controlling for accelerometer bias drift of a strapdown system, such as the iMAR INAT system, including tie-line leveling and signal interleaving with a paired thermally-stabilized gravimeter (e.g. DGS AT1A or ZLS). We also explore ways of optimally-combining free-air anomaly estimates from a suite of meters, each with differing sensitivities over varying frequency ranges, exploring well-tested statistical techniques such principle component analysis and ensemble Kalman filters. In addition to this Ross Ice Shelf baseline comparison, we extend these methods to other concurrent gravimetry datasets: from a Twin Otter-based Lacoste-Romberg and iMAR INAT survey flown by BAS as part of the ITGC, and a comparison of AIRGrav with an iMAR-DGS suite from Northern Greenland.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.G33B0689P
- Keywords:
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- 1217 Time variable gravity;
- GEODESY AND GRAVITY;
- 1219 Gravity anomalies and Earth structure;
- GEODESY AND GRAVITY;
- 1244 Standards and absolute measurements;
- GEODESY AND GRAVITY;
- 1294 Instruments and techniques;
- GEODESY AND GRAVITY