Processed line aeromagnetic data from the FISS 2016 surveys covering the Filchner and Halley Ice Shelves, and the English Coast (western Palmer Land), West Antarctica (2016/2017)

• Main Authors: Jordan, Tom, Corr, Hugh, Robinson, Carl
• Format: Dataset
• Language: English
• Published: NERC EDS UK Polar Data Centre 2021
• Subjects: "EARTH SCIENCE","SOLID EARTH","GEOMAGNETISM","MAGNETIC FIELD","MAGNETIC ANOMALIES"; Aerogeophysics; Aeromagnetics; Antarctica; Magnetics; Antarctic; Antarctic Peninsula; Austral; West Antarctica; Palmer Land; Filchner Ice Shelf; Brunt Ice Shelf; Butterworth; Slessor; Sky-Blu; Antarc*; British Antarctic Survey; Ice Shelf; Ice Shelves
• Online Access: https://dx.doi.org/10.5285/83c4f40e-abd4-4f76-a7db-d7307bd56b55; https://data.bas.ac.uk/full-record.php?id=GB/NERC/BAS/PDC/01577

Three separate airborne radar surveys were flown during the austral summer of 2016/17 over the Filchner Ice Shelf and Halley Ice Shelf (West Antarctica), and over the outlet glacier flows of the English Coast (western Palmer Land, Antarctic Peninsula) during the Filchner Ice Shelf System (FISS) project. This project was a NERC-funded (grant reference number: NE/L013770/1) collaborative initiative between the British Antarctic Survey, the National Oceanography Centre, the Met Office Hadley Centre, University College London, the University of Exeter, Oxford University, and the Alfred Wenger Institute to investigate how the Filchner Ice Shelf might respond to a warmer world, and what the impact of sea-level rise could be by the middle of this century. The 2016/17 aerogeophysics surveys acquired a total of ~26,000 line km of aerogeophysical data. The FISS survey consisted of 17 survey flights totalling ~16,000 km of radar data over the Support Force, Recovery, Slessor, and Bailey ice streams of the Filchner Ice Shelf. The Halley Ice Shelf survey consisted of ~4,600 km spread over 5 flights and covering the area around the BAS Halley 6 station and the Brunt Ice Shelf. The English Coast survey consisted of ~5,000 km spread over 7 flights departing from the Sky Blu basecamp and linking several outlet glacier flows and the grounding line of the western Palmer Land, including the ENVISAT, CRYOSAT, GRACE, Landsat, Sentinel, ERS, Hall, Nikitin and Lidke ice streams. Our Twin Otter aircraft was equipped with dual-frequency carrier-phase GPS for navigation, radar altimeter for surface mapping, wing-tip magnetometers, an iMAR strapdown gravity system, and a new ice-sounding radar system (PASIN-2). We present here the processed line aeromagnetic data collected using wing-tip magnetometers mounted in the BAS aerogeophysically equipped Twin Otter aircraft. Data are provided as XYZ ASCII line data. : The dataset available here includes all channels from raw through to levelled and microlevelled products. Channel naming and processing follows SCAR/ADMAP2 data release protocols. channel description: Line:Flight Flight line and flight number. Format XYYY:ZZ X=L (line), T(Tie), P or S (legacy survey) Lat Lon Height_WGS84 Direct GPS navigation information, accurate to ~5 m. Date Time UTC time values MagR Raw magnetic data (nT) Tcorr Tip correction for aircraft systems (nT) RefField IGRF reference field (nT) MagRTC Mag corrected for Tips and reference field NOTE No compensation correction (nT) BCorr Base station correction with 30 min filter and after mean removal (nT) MagBRT Mag after base station correction (nT) - B=base corrected, T=tip corrected, R=regional corrected Acorr Heading correction - only applicable to some lines (nT) MagF Final mag field prior to levelling (nT) MagL Statistically levelled anomalies (nT) MagML Micro-levelled anomalies (nT) x y Polar Stereographic coordinates (m) FISS - 16/17 season Slessor: Opportunistic aeromagnetic data collected during an airborne radar survey. Flights with 2.5 km line spacing. Standard ADMAP2 processing flow, including IGRF and Tip tank corrections. However, due to the opportunistic nature of the survey no compensation calibration for aircraft motion was performed. Base station correction based on local base station filtered with 30 minute filter, after removal of mean base station value across the survey period. For levelling additional data from ADMAP2 compilation and ICEGRAV 2013 surveys was included to provide additional ties. These are coded as P or S lines, rather than L or T. Microleveling utilised gridded line data filtered with 10 km Butterworth How Pass, and cosine directional filter (with Azimuth 140, and degree 1). Filtered correction was sampled onto lines and low-pass filtered with 12 km Butterworth filter. Support Force processing notes: Opportunistic aeromagnetic data collected during an airborne radar survey. Flights with 2.5 km line spacing. Standard ADMAP2 processing flow, with IGRF correction. Tip corrections were not performed as these errors were restricted to areas outside the main survey grid, also due to the opportunistic nature of the survey no compensation calibration for aircraft motion was performed. Base station correction based on local base station filtered with 30 minute filter, after removal of mean base station value across the survey period. Microleveling utilised gridded line data filtered with 10 km Butterworth How Pass, and cosine directional filter (with Azimuth 52.5, and degree 0.75). Filtered correction was sampled onto lines and low-pass filtered with 12 km Butterworth filter. Baily Opportunistic aeromagnetic data collected during an airborne radar survey. Flights with 2.5 km line spacing. Standard ADMAP2 processing flow, including IGRF and Tip tank corrections. However, due to the opportunistic nature of the survey no compensation calibration for aircraft motion was performed. Base station correction based on local base station filtered with 30 minute filter, after removal of mean base station value across the survey period. Microleveling utilised gridded line data filtered with 10 km Butterworth How Pass, and cosine directional filter (with Azimuth 111, and degree 1). Filtered correction was sampled onto lines and low-pass filtered with 12 km Butterworth filter. Recovery Opportunistic aeromagnetic data collected during an airborne radar survey. Flights with 2.5 km to 5 km line spacing, and an array of oblique lines. Standard ADMAP2 processing flow, including IGRF and Tip tank corrections. However, due to the opportunistic nature of the survey no compensation calibration for aircraft motion was performed. Base station correction based on local base station filtered with 30 minute filter, after removal of mean base station value across the survey period. Microleveling utilised gridded line data filtered with 10 km Butterworth How Pass, and cosine directional filter (with Azimuth 33.6, and degree 1). Filtered correction was sampled onto lines and low-pass filtered with 12 km Butterworth filter.