Measurements of ice velocity on the surface of the ice sheet in Wilkes Land East Antarctica were made along the routes of oversnow traverses operating out of Casey (66.6 S 110 E). In general, measurements were made at a nominal spacing of 50 km. Additional measurements were made at closer spacing in some areas in order to resolve finer scale variation in the flow pattern. Three main routes were ... covered: two routes (east at latitude 69 S and west at latitude 68.5 S) approximately followed the line of the 2000 m elevation contour, and a third route headed south from summit of Law Dome ice cap along the line to Vostok station.
All velocity data were derived from positions determined using Doppler Satellite Positioning techniques with data collected from the (US) NAVSAT systems using JMR receivers, with the doppler data processed in combination with Precise Ephemeris data supplied by the (US) DMAHTC and the DOPPLR software packages. Processing of the data were carried out by the Australian Division of National Mapping.
The time interval between first and last position observations was three years for the western route, six years for the southern route, and three to five years for the eastern route.
These data form part of the data collected for ASAC projects 458 (Characteristics, Dynamics and Mass Budget of the Ice Sheet in Wilkes Land) and 2224 (Glacier dynamics and mass discharge from the Antarctic ice sheet, 45 degrees -160 degrees E) - (ASAC_458, ASAC_2224).
The fields in this dataset are:
Station Latitude Longitude Velocity Azimuth
The printouts from the recording and reduction of the doppler observations have been archived at the Australian Antarctic Division.
All logbooks have been archived at the Australian Antarctic Division.
Copies of the document details forms for the logbooks is available for download from the provided URL.
All velocity data were derived from positions determined using Doppler Satellite Positioning techniques with data collected from the (US) 'NAVSAT' systems using 'JMR' receivers, with the doppler data processed in combination with Precise Ephemeris data supplied by the (US) 'DMAHTC' and the 'DOPPLR' software packages. Processing of the data were carried out by the Australian 'Division of National ... Mapping'. The time interval between first and last position observations was three years for the western route with generally only two occupations of each station / marker, six years for the southern route with up to three occupations, and three to five years for the eastern route with between two and four occupations.
The accuracy of an individual position determination was typically at the 1-2 m level (DMAHTC data) with data from a sufficient number of satellite passes and usually requiring three or more days of data collection for position determination. The accuracy of the velocity value varies with the magnitude of the velocity, number of position observations included in the evaluation, and the total time interval represented by the dates of all the occupations of the station/marker. The goal was to achieve the following or better accuracy: 10 % in magnitude, and five degrees in azimuth. In general this was achieved, with accuracies of a few per cent with the larger velocity values.
Data available on request to AADC / Neal Young. The data are available for download from the URL given below.
ACE CRC AND AUSTRALIAN ANTARCTIC DIVISION
Private Bag 80
Province or State:
Young, N.W. (1979), Application of doppler satellite observations to the study of ice-flow in East Antarctica-Problems peculiar to doppler surveys in high latitudes., Proceedings of 2nd International Geodetic Symposium on Satellite Doppler Positioning, 1 (of 2 volumes), 373, 391, University of Texas, DMA and ARL
Young, N.W., Goodwin, I.D., Hazelton, N.W.J. and Thwaites, R.J. (1989), Measured velocities and ice flow in Wilkes Land, Antarctica, Annals of Glaciology, 12, 192-197