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:

Ferris, J. (2020). Processed line aeromagnetic data over the Black Coast (1996/97 season) (Version 1.0) [Data set]. UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation. https://doi.org/10.5285/4FD848A4-5C86-4324-8574-1A33CACBA10B

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:

Black coast aeromagnetic data presented in Ferris et al. (2002). The dataset available here includes channels from raw through to levelled products, although not all typical corrections have been applied to the Black Coast dataset. 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. [nT]

MagBRTC- calculated as MagBRTC= MagRTC- Bcorr. [nT]

ACorr- Additional correction applied to compensate for heading errors.

MagF- Final mag value before levelling.

MagL- Statistically levelled mag data.

Basic channel description:

Basic Channels

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: -66

Longitude of false origin: -70

Latitude of 1st standard parallel -76.4

Latitude of 2nd standard parallel -63.4

False easting 0

False northing 0

Positioning for the Black Coast survey used dual-frequency, Trimble 4000SSE GPS receivers, one in the aircraft linked to a TECOM antenna, the other as a base station at Rothera Research Base (Ferris et al., 2002). Positions are calculated for the phase centre of the aircraft antenna. All positions (Lat, lon and height) are referred to the WGS1984 ellipsoid.

Data quality:

Survey flights were restricted to times when a minimum of five satellites could be recorded both on the aircraft and at the ground station. The relative Dilution of Precision (RDOP) never rose above 5.0. Post-flight continuous kinematic differential GPS processing was carried out using Trimble GPSurvey software. RMS errors were ca. 0.08 m and the absolute positional accuracy is thought to be better than 5 m.

Caesium-vapour magnetometers have a sensitivity of 0.005 nT, but the Dash-7 serves a dominantly logistic role, and so, it cannot provide the same data quality as a dedicated aeromagnetic survey plane. As a result, fourth digital differences (a commonly used figure of merit) for a typical uncompensated flight line are within 1.5 nT and this value drops to below 1 nT after compensation.

No values are given for MagC, TCorr, MagRTC, BCorr, MagBRTC and SCorr. These channels are included for compatibility with ADMAP2 convention.