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  • This dataset contains ice motion observations made under the Australian Antarctic Program, Projects 4593 and 4506. Data was obtained using two Spotter wave buoys (Sofar Ocean Technologies), hereafter wave buoys, and two open-source ice motion loggers, hereafter ice buoys. Instruments were deployed on (land)fast ice on the eastern rim of the Amery Ice Shelf, Antarctica (69.2 degr. S, 76.3 degr. E), on 7 December 2019. After the break-up of the ice occurring at the start of January 2020, instrumentation started to drift with the ice. Last transmission recorded was on 10 March 2020. The wave buoys measure their 3-axis motion at 2.5 Hz through GPS and have an accuracy of approximately 2 cm for the recorded significant wave height. The ice buoys measure motion in 9-degrees-of-freedom at 10Hz using a VectorNAV VN-100 IMU, with an accuracy of O(mm) for short waves and O(cm) for long waves. Both instruments also record their geographical location through GPS. Full time series of their motion is processed on board and summaries are send through Iridium. For the ice buoy wave spectra were transmitted roughly every 3 hours. The transmission interval for the wave boys was variable, ranging from every half an hour to every 3 hours. Data transmitted by the wave buoys was either integral wave properties or the complete wave spectrum. In the dataset, WB and IB are abbreviations for wave buoy and ice buoy, respectively. This dataset includes all observations transmitted during the measurement campaign (WB1, WB2, IB1, IB2). E = wave energy spectrum (m2/s); f = wave frequency (Hz); a1, a2, b1, b2 = Fourier coefficients; Hs = significant wave height (m); Tp = peak period (s); Tm01 = mean period (s); Dir_peak/mean = peak and mean wave direction and 'spr' refers to spreading; volt = battery voltage (V). Time is in UTC, and in Matlab’s datenum format (i.e. the number of days since year 0000). The geographical coordinates ‘lat’ and ‘lon’ (latitude and longitude, respectively) are in degrees. Note, as the ice buoys transmit the GPS coordinates and wave data in separate data messages, for the ice buoys ‘time’ refers to the reference time of the wave properties Hs and Tp, whereas ‘GPStime’ refers to the reference time of the geographical coordinates (lat and lon). For the wave buoy, all data is transmitted at the same time.

  • Raw data from two autonomous phase sensitive radar (ApRES) installations on Amery Ice Shelf, East Antarctica. Site, Lat, Lon, Installation, Retrieval AM06_borehole, -70.228432, 71.391693, 17-Jan-2015, 03-Feb-2018 AM06_downstream, -70.225635, 71.395988, 09-Mar-2015, 03-Feb-2018 ApRES phase-sensitive radar is a low-power, light-weight instrument developed in a collaboration between BAS and University College London. It is a 200-400 MHz FMCW radar, with a 1-second chirp, run by controller. Each radar was set to produce a burst of 50 chirps every 4 hrs, and a config file with radar settings is provided with each dataset. Files: *.dat - binary files containing raw data config.ini - config file containing all radar settings used for each site Software for processing the raw data can be obtained from Dr. Keith Nicholls, British Antarctic Survey. Limited Matlab scripts are provided here to open the raw data. Command: f=fmcw_load('filename.DAT') Data structure: Variable name Unit Description Nattenuators - Number of attenuation settings used (1 or 2) Attenuator_1 dB RF Attenuator value 1 Attenuator_2 dB RF Attenuator value 2 ChirpsInBurst - Number of chirps in burst TimeStamp day Time of first chirp (Matlab date format) Temperature_1 C Instrument temperature 1 Temperature_2 C Instrument temperature 2 BatteryVoltage V Battery voltage Burst - Number of burst in file FileFormat - Identifies file format from different equipment versions vif V Voltage chirpTime day Time of chirp (Matlab date format) filename - Filename SamplesPerChirp - Number of samples per chirp fs Hz Sampling frequency f0 Hz Start frequency K rad/s/s Chirp gradient (200MHz/s) f1 Hz Stop frequency B Hz Bandwidth fc Hz Centre frequency er - Material permittivity ci m/s Velocity in material lambdac m Centre wavelength t s Sampling time (relative to first sample) f Hz Frequency stamp for sample

  • This dataset contains time-series of current profiles from beneath the Amery Ice Shelf obtained from an Acoustic Doppler Current Profiler (ADCP) (RDI 300 kHz broadband Workhorse) on the AM06 mooring string. The ADCP was positioned ~108 m below the base of the ice shelf and oriented to look upwards (i.e. toward the base of the shelf) to examine the water cavity boundary layer and the range (distance) from the instrument to the ice-ocean interface. Accounting for instrument displacement by ocean currents, changes in range are expected to be indicative of basal melting. The dataset contains ~1 year of velocity data from 07/01/2010 sampled at 30 minute intervals. In the vertical, the ADCP sampled 27 bins, with a measurement every 4m. Key variables in the dataset include ocean velocity (u, v, w), instrument orientation (pitch, roll, heading) and distance from the instrument to the ice shelf base (btdistance), as well as quality control parameters such as beam correlation (avbeamcor), strength of the return/echo amplitude (ampav) and velocity error (errv). Two data files are archived here, the raw data "adcp_am06_1noqc.nc" and the quality-controlled data "adcp_am06_1qc.nc". Descriptions of the quality control and post-processing are found in "readme.rtf" and notes and preliminary plots are found in "borehole2010_11.pdf".