Denman Terrestrial Campaign - Ground-based gravity transect

Full description

New ground-based gravity and GNSS data set collected at nine sites along a ~14 km transect across the Denman Glacier system during the Denman Terrestrial Campaign 2023/24. The survey was conducted along the existing ICECAP airborne geophysical flight line ASB/JKB2c/Y11b, enabling direct comparison between ground-based and airborne observations. Coincident GNSS observations are provided for precise station positions and ellipsoidal heights.

Lineage

Progress Code: completed

Maintenance and Update Frequency: notPlanned

Statement: In January 2024, we collected nine ground-based gravity measurements along a ~14 km transect across the Denman Glacier (spacing ~ 1.7 km). We used a Scintrex CG-5 Autograv (resolution 0.001 mGal; typical station repeatability of 5 μGal under stable conditions; long-term drift below 0.02 mGal/day (See Scintrex CG5 Manual, 2017)), with daily base ties at Bunger Hills and loop closures including the Casey Station absolute site to control drift. Field readings from the CG-5 were tied to an absolute reference by calibrating against the Casey Station fundamental value of 982380.48867 mGal (Lon: 110.5226, Lat: -66.2820, height: 19 m, positional error: 3 m, gravity error: 30 μGal). Coordinates were determined from dual-frequency Trimble GNSS. Rover trajectories were post-processed kinematically (PPK) in Emlid Studio v1.5; the local PPK network was tied to an AUSPOS (ITRF2014) solution. On the Glacier, we positioned one GNSS Antenna at a mid-line base (Lon: 99.4622, Lat: -67.1976, height = 804.817 m ellipsoidal) for ~7 hours. 'Casey Base Station': All measurements at the Casey station as summary in the Casey_Station.xlsx sheet, raw data in the .TXT files, and 6Hz data in the .SMP files. 'Bunger Hills Control': All measurements at the Bunger Hills camp as summary in the Bunger_control.xlsx sheet. Several folders with dates contain backups of raw data in the .TXT files, 6Hz data in the .SMP files, and GNSS files (only on two days) with coordinates of the three drifferent control points in the Bunger Hills camp. 'Transect': All measurements at the transect (on January 3rd only at 3 of 9 sites, on January 7th at all 9 sites). Summary of gravity in Transect.xlsx, summary of coordinates in Coordinates_Height_Site.xlsx, Trimble data in 'GNSS' folder, gravimeter outputs in 'raw gravimeter files' folder. Summary gravity files contain Station Number (Station no), Location (Site/name of location), gravimeter tide correction (TC), standard deviation (SD), horizontal tilts (TiltX, TiltY), height given by gravimeter (usually not correct), Comments, and Date.

Notes

Credit
This research was supported by the Australian Research Council Special Research Initiative, Australian Centre for Excellence in Antarctic Science (Project Number SR200100008).

Credit
This research was supported by the Australian Research Council Special Research Initiative, Australian Centre for Excellence in Antarctic Science (Project Number SR200100008). This work was supported by fieldwork that occurred under AAS4630.