On Friday, 06 November 2015 from 8:00 a.m. to 5:00 p.m. (USA Mountain Time), our FTP services, which also includes automated data requests from services such as Polaris and the GLAS Subsetter, will be unavailable because of system maintenance. We apologize for any inconvenience this may cause you.
The above overview map is a subscene from the USGS 1-km AVHRR mosaic (Ferrigno et al., 1996). Velocity data were derived from the Landsat scenes listed below. To view image data select Velocity Map or Data Set Map, or use the links on the overview image.
Surface velocities and elevations of Byrd Glacier were determined by photogrammetric methods (bundle block aerial triangulation) from two sets of aerial photographs (scale about 1:48,000) taken on 6 December 1978 and 31 January 1979. The data were reported as three-dimensional coordinates of points at these two epochs. Velocities were calculated from the two positions of the same surface points and the time interval between the two flights.
Natural features, such as crevasses, seracs, or dunes, were identified and marked on both sets of photographs. Seventy-one fixed points on rock outcrops at the glacier's lateral margins were also identified and marked in the same way. 13 control points on the perimeter of the area were established by ground survey. All these points were measured on the photographs by a stereo comparator, and their elevations and planimetric terrain coordinates were determined analytically by a rigorous least-squares adjustment of the two blocks of photographs. This yielded coordinates of 1467 terrain points from 6738 image points (13,476 photo coordinate measurements) on 322 photographs. There are 470 velocity vectors calculated for this data set.
Also see:Related Publications
Brecher, Henry H. 1982. Photogrammetric determination of surface velocities and elevations on Byrd Glacier. Antarctic Journal of the U.S., XVII(5): 79-81.
Brecher, Henry H. 1986. Surface velocity determination on large polar glaciers by aerial photogrammetry. Annals of Glaciology, VIII: 22-26.
Van der Veen, C.J., and I.M. Whillans. 1989a. Force Budget: I. Theory and numerical methods. Journal of Glaciology, 35(119): 53-60.
Van der Veen, C.J., and I.M. Whillans. 1989b. Force Budget: II. Application to two-dimensional flow along the Byrd Station Strain Network, Antarctica. Journal of Glaciology, 35(119): 61-67.
Whillans, I.M., Y.H. Chen, C.J. van der Veen, and T.J. Hughes. 1989c. Force Budget: III. Application to Three-Dimensional Flow of Byrd Glacier, Antarctica. Journal of Glaciology, 35(119): 68-80.
Access the tabular velocity data for the Byrd Glacier 1978-1979
Top of Page