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EARTH SCIENCE > Cryosphere > Glaciers/Ice Sheets

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  • Over 20,000 km of new aerogravity data were acquired over Palmer Land during the 2002-2003 Antarctic campaign. Profile lines were oriented E-W with N-S tie lines. Line spacing was 5 km, tie lines were 25 km apart and nominal flight altitude was 2800 m. Differential, carrier phase, kinematic GPS processing methods provided the vertical and horizontal accelerations, which dominate the raw aerogravity signal. Levelled airborne gravity data have mean accuracies of 3 mGal. We present here the processed line aerogravity data collected using Lacoste and Romberg air-sea gravity meter S83. Data are provided as XYZ ASCII line data.

  • Gravity, magnetic and radar data were acquired during a joint UK-Argentina (BAS/IAA) project, during the austral summer 1998-1999. 10,771 line km of data were acquired using a BAS Twin Otter, covering an area of 21,000 km2 that comprises the James Ross Island archipelago and the NW corner of the Weddell Sea. Gravity and magnetic data were simultaneously acquired at a constant barometric height of 2000 m, providing a terrain clearance of approximately 100 m over the highest peaks. The main flight lines were flown along an E-W direction with 2000 m spacing over James Ross Island and at 4000 m interval offshore. Tie lines, oriented meridionally, were spaced 10,000 m and extended beyond the magnetic survey to provide a regional context to the survey area as required also for airborne gravity data analysis. Magnetic data were acquired at a frequency of 10 Hz using vapour cesium magnetometers mounted on the aircraft wing tips, and resampled to 1 Hz after compensation for manoeuvre noise. A triaxial fluxgate magnetometer was mounted close to the tail of the aircraft, providing magnetic attitude information used in the data compensation. However, gravity acquisition defines that turbulent conditions are avoided and so manoeuvre noise is generally minimal. Ashtech Z12 duel frequency GPS receivers were used for survey navigation and for post-processing of the GPS data. Magnetic data were de-spiked to remove avionics noise and then smoothed (- 300 m low pass filter), before re-sampling from 10 to 1 Hz. The data were first corrected for diurnal variations using low-pass filtered base station data (30 min low-pass filter). For the internal field we used the Definitive Geomagnetic Reference Field Model 1995. The final data processing step was network levelling and microlevelling (Ferraccioli et al., 1998). We present here the processed line aeromagnetic data collected using scintrex cesium magnetometers mounted on the BAS aerogeophysical equipped Twin Otter. Data are provided as XYZ ASCII line data.

  • Analysis of shallow ice cores collected in the region of subglacial Lake Ellsworth. Three cores drilled to ~20 m depth. Two cores returned to UK for analysis. One core measured for density-depth in the field, then discarded. One of the two cores returned to UK has been sent to Bristol University for major anion/cation analysis; the other core is at the British Antarctic Survey (BAS) and will be analysed for accumulation rate. Density analysis is complete. Chemical analysis is complete. Accumulation analysis is in progress.

  • This data was collected during two Antarctic field seasons (2013-14, 2014-15) using two Leica GS10 dual-frequency Global Position Systems (dGPS). We installed 53 2m aluminium stakes in the snow surface along lines perpendicular to ice divides on four ice rises in the Ronne Ice Shelf region. In each season we used the dGPS units to measure the position of each pole. During most position measurements we deployed a rover unit for 20 minutes at each stake while a static base station dGPS unit was left in place for 5 or more hours. In the minority of cases the power to the base station unit failed and data from the rover unit is not accompanied by base-station data.

  • During the austral summer of 2001/02 five thousand line kilometres of airborne radio echo sounding and aeromagnetic data were collected in the region of three tributaries of Slessor Glacier, East Antarctica, which drains into the Filchner Ice Shelf. We present here the processed bed elevation picks from airborne radar depth sounding acquired using the BAS aerogeophysicaly equipped Twin Otter aircraft. Data are provided as XYZ ASCII line data. Data were collected as part of UK Natural Environment Research Council (NERC) grant GR3/AFI2/65

  • This data set contains aeromagnetic data collected during the WISE/ISODYN project. This collaborative UK/Italian project collected ~ 61000 line km of new aerogeophysical data during the 2005/2006 austral summer, over the previously poorly surveyed Wilkes subglacial basin, Dome C, George V Land and Northern Victoria Land. We present here the processed line aeromagnetic data collected using scintrex cesium magnetometers mounted on the BAS aerogeophysical equipped Twin Otter. Data are provided as XYZ ASCII line data.

  • 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.

  • A British Antarctic Survey Twin Otter and survey team acquired 8,300 line-km of magnetic data during the Austral summer of 1998/99. Gravity and radio-echo data were acquired simultaneously with the magnetic data at a compromise constant barometric height of 2,200 m, which provides a terrain clearance of 100 m over the highest peaks. Two separate surveys were conducted; one at 5 km line spacing (tie lines at 20 km) over and stretching beyond the southern extent of the Forrestal range (main survey), and one at 2 km line spacing (tie lines at 8 km) covering the Dufek Massif (detailed survey). Wing-tip-mounted cesium vapour magnetometers acquired data at 10 Hz, which was resampled to 1 Hz after deletion of data corrupted by the radio echo transmissions. It is not possible to compensate the magnetic data for maneuver noise after this process as the data are under-;sampled with respect to maneuver noise. However, because gravity data was being acquired at the same time, turbulent conditions were avoided and so maneuver noise was at a minimum. Ashtech Z12 dual frequency GPS receivers were used for survey navigation. Pseudorange data were supplied to a Picodas PNAV navigation interface computer, which was used to guide the pilot along the pre-planned survey lines. The actual flight path was recovered, using carrier-phase, continuous, kinematic GPS processing techniques. All magnetic and pseudorange navigation data were recorded at 1 Hz on a Picodas PDAS 1000, PC-based data acquisition system. Data were de-spiked and then smoothed (~100 m low pass filter), before re-sampling from 10 to 1 Hz. The data were IGRF corrected, leveled and reduced to the pole in the field. A 2.5 km cell grid was produced. The negative bias to the anomaly amplitudes is a result of the poorly defined IGRF in this area. We present here the processed line aeromagnetic data acquired using scintrex cesium magnetometers mounted on the BAS aerogeophysical equiped Twin Otter. Data are provided as XYZ ASCII line data.

  • During the 1996-1997 Antarctic field season, an aeromagnetic survey was carried out by the BAS to the west of Alexander Island, designed to investigate the Charcot Island anomaly. The presented data was collected using wingtip mounted Caesium-vapour magnetometers. Magnetic effects due to aircraft motion were actively compensated using a triad of fluxgate magnetometers mounted in the tail of the aircraft. Data are provided as XYZ ASCII line data.

  • Meteorological data collected on Larsen Ice Shelf including pressure, temperature, wind speed and direction.