Further by downloading this data the user acknowledges that they agree with the NERC data policy (), and the following conditions:

1. To cite the data in any publication as follows:

Ferraccioli, F., Damaske, D., Finn, C., Bell, R., Jordan, T., Robinson, C., & Frearson, N. (2020). Antarctica's Gamburtsev Province (AGAP) Project - Aeromagnetic data (2007-2009) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/91DF43DF-E3FD-4637-9091-E75F623E2B07

2. The user recognizes the limitations of data. Use of the data is at the users' own risk, and there is no warranty as to the quality or accuracy of any data, or the fitness of the data for your intended use. The data are not necessarily fully quality assured and cannot be expected to be free from measurement uncertainty, systematic biases, or errors of interpretation or analysis, and may include inaccuracies in error margins quoted with the data.

Methodology:

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

Data quality:

The accuracy of the processed data is approximately 1 nT.