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

1. To cite both the data and literature reference in any publication as follows:

DATA REFERENCE

Jordan, T., Corr, H. & Robinson, C. "Aeromagnetic survey across the Brunt Ice Shelf, 2017" (2018) Polar Data Centre, Natural Environment Research Council, UK Research & Innovation, UK

doi:10.5285/410ee2f9-2d22-4155-aaed-43b93a7c3d62

LITERATURE REFERENCE

Jordan and Becker 2018 In prep.

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:

Raw line aeromagnetic data from the 2017 Brunt Survey were corrected for the regional geomagnetic field (IGRF) and diurnal variations recorded by the Halley VI magnetic fluxgate base station. Base station corrections were filtered with a 30 minute filter to ensure short wavelength signals, likely only seen at the base station, were not transferred to the airborne dataset. Additional corrections for offsets induced by aircraft operations and flight heading direction were also applied. Note magnetic compensation was not carried out as the opportunistic nature of the dataset did not allow for a suitable calibration flight.

To further improve the levelling of the 2017 Brunt aeromagnetic survey data from ICEGRAV 2013 survey (Forsberg et al., 2017) was also considered, but is not included in this data download. Magnetic data from both surveys were continued to a common altitude of 500m. To minimize errors due to downward continuation data were filtered with a low pass filter two times the downward continuation distance. After continuation the data were statistically levelled to minimize survey to survey offsets and residual errors along individual lines.

Data collection:

Data was collected using the BAS aerogeophysicaly equipped twin otter VP-FBL. Magnetic data was collected using wing tip mounted Scintrex CS-3 High Sensitivity Cs magnetometers. Data was recorded at 10 Hz on a PicoEnvirotec logging system, before being decimated to 1 Hz for subsequent processing. Additional base station information from a calibrated long-term fluxgate sensor at Halley Station was used during data processing.

Data quality:

The standard deviation of the crossover error of the final statistically levelled dataset was 8.21 nT for 313 intersections, after removing 9 anomalously high (>30 nT) crossover values.

Resolution: The line spacing for the main survey area is 5km, with regional lines spaced ~18 km apart. The provided data is sampled at 1Hz, which equates to a 60m along track sample spacing.