Processed line aeromagnetic data over the Black Coast (1996/97 season)

• Main Author: Ferris, Julie
• Format: Dataset
• Language: English
• Published: UK Polar Data Centre, Natural Environment Research Council, UK Research & Innovation 2020
• Subjects: "EARTH SCIENCE","SOLID EARTH","GEOMAGNETISM","MAGNETIC ANOMALIES"; "EARTH SCIENCE","CRYOSPHERE","GLACIERS/ICE SHEETS"; Aerogeophysics; Aeromagnetics; Antarctica; Antarctic; Weddell Sea; Weddell; Rothera; Ferris; Rothera Station; Black Coast; Antarc*
• Online Access: https://dx.doi.org/10.5285/4fd848a4-5c86-4324-8574-1a33cacba10b; https://data.bas.ac.uk/full-record.php?id=GB/NERC/BAS/PDC/01342

Using the British Antarctic Survey's DeHavilland Dash-7, approximately 10,000 line-km of data were collected from the Black Coast and adjacent Weddell Sea embayment, which is situated ca. 600 km southeast of the airfield at Rothera Station . Flight lines were spaced at 10-km intervals with perpendicular tie lines spaced at 40 km. Where time and fuel allowed, selected areas were infilled at a 5-km line spacing. The marine part of the survey was flown at around less than 1000 m above sea level.We present here the processed line aeromagnetic data acquired using scintrex cesium magnetometers mounted on the BAS aerogeophysical equiped Dash-7. Data are provided as XYZ ASCII line data. : 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. : 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.