Antarctica's Gamburtsev Province (AGAP) Project - Aeromagnetic data (2007-2009)

• Main Authors: Ferraccioli, Fausto, Damaske, Detlef, Finn, Carol, Bell, Robin, Jordan, Tom, Robinson, Carl, Frearson, Nicholas
• Format: Dataset
• Language: English
• Published: UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation 2020
• Subjects: "EARTH SCIENCE","LAND SURFACE","TOPOGRAPHY","TERRAIN ELEVATION"; "EARTH SCIENCE","SOLID EARTH","GEOMAGNETISM","MAGNETIC FIELD","MAGNETIC ANOMALIES"; Gamburtsev Province; aerogeophysics; magnetics; Antarctic; East Antarctica; Antarc*; Antarctica; Ice Sheet; International Polar Year; United States Antarctic Program
• Online Access: https://dx.doi.org/10.5285/91df43df-e3fd-4637-9091-e75f623e2b07; https://data.bas.ac.uk/full-record.php?id=GB/NERC/BAS/PDC/01308

Aeromagnetic data collected as part of the seven nation Antarctica's Gamburtsev Province (AGAP) expedition during the International Polar Year 2007-2009, and used to acquire a detailed image of the ice sheet bed deep in the interior of East Antarctica. Airborne geophysical methods were used to understand the fundamental structure shrouded beneath Dome A. Two twin Otter aircraft - one BAS, one United States Antarctic Program (USAP) - equipped with ice-sounding radars, laser ranging systems, gravity meters and magnetomemeters, operated from camps located on either side of Dome A. : The aeromagnetic system used was manufactured by Scintrex/PicoEnvirotec and has also extensively been used in Antarctica before. Aeromagnetic data was collected using two optically pumped Scintrex Cs-3 sensors which were fitted in pods and mounted in wing-tip configuration on the Twin Otter. A fluxgate magnetometer provided the data to compensate for the magnetic effect of the aircraft and a magnetic base station was deployed to monitor external magnetic field variations. In total, 120,000 line km of data were acquired from a nested survey grid with line spacing of 5km and tie lines ~ 33 km apart. AGAP aeromagnetic data presented in Ferraccioli et al. (2011). The dataset available here includes all channels from raw through to levelled, and draped products. Channel naming follows SCAR/ADMAP2 data release protocols. Magnetic data channels and processing flow: MagR- Raw magnetic total field intensity data (nT). MagC- Compensated, or low pass filtered magnetic data (nT). Adjustments to compensate for aircraft roll, pitch and yaw were applied (see Ferraccioli et al, 2007 for details). RefField- Geomagnetic reference field value for which the magnetic data has been compensated. IGRF model 2005 as implemented in Geosoft (nT). MagRTC- Compensated magnetic value adjusted for Tip tanks (where used) and geomagnetic reference field values. MagRTC= MagR- RefField (nT). BCorr- Low pass filtered (60 minute) magnetic base station correction. Data from three base stations were used for different portions of the survey (BCorr_AGAP_N, BCorr_AGAP_S, BCorr_AGAP_SP), along with a merged value between North and South base stations (BCorr_AGAP_NS). MagBRTC- calculated as MagBRTC= MagRTC- Bcorr (nT). ACorr- Additional correction applied to compensate for heading errors. MagF- Final mag value before levelling (nT). MagL- Statistically levelled mag data (nT). MagML- Microlevelled magnetic data following technique of (Ferraccioli et al., 1998). (nT) Note tie lines are not included in the microlevelled data channel. Basic channel description: Line name Line Number Flight ID Sequential flight number x x projected meters* y y projected meters* Lon Longitude WGS 1984, Lat Latitude WGS 1984, Height_WGS1984 Aircraft altitude (meters) in WGS 1984, Date Date of flight in time format e.g. 2006/01/08 Time Time (UTC) of flight e.g. 23:52:42.0 *Projected coordinates (x and y) are in Lambert conic conformal with two standard parallels defined as follows: Latitude of false origin: -80 Longitude of false origin: 80 Latitude of 1st standard parallel -83 Latitude of 2nd standard parallel -77 False easting 2000000 False northing 2000000 : The accuracy of the processed data is approximately 1 nT.