Ice Velocities on the Mizuho Plateau

Ice Velocities on the Mizuho Plateau
This overview map is a subscene from the USGS 1 km AVHRR mosaic (Ferrigno et al., 1996).

Access Data
Map of the Mizuho Plateau velocities

Data Acquisition Method

Positions were measured at two different times using a triangulation chain survey. The first was done in 1969; the second in 1973-1974. Quoting from Naruse 1978:

The triangulation chain stretched along the parallel of 72 degrees South for a total distance of 250 km between A001 at the southeast end of the Yamato Mountains and A164 (S240) .... Composed of 164 stations, the chain formed a series of 162 triangles ....

Both the first and the second survey of the triangulation chain were conducted principally by angle measurements with Wild T2 theodolites. ...

With the aim of correcting the accumulation of errors, the distance was measured with a radiowave distance meter (Cubic DM-20) and the azimuth was observed by shooting the sun for one side of every 10 to 15 triangles. ...

The horizontal vector of ice movement was calculated at each triangulation station from the difference between two geodetic positions in 1969 and 1973-1974, which were obtained by net-adjustment. The horizontal displacement delta_S and its direction beta indicated by the azimuth clockwise from the north point are given as follows:

delta_S = sqrt( (p delta_phi)^2 + (q delta_lambda)^2 )
beta = arctan( q delta_lambda / (p delta_phi) )

where delta_phi and delta_lambda are respectively the difference of the latitudes and that of longitudes of a station between two measurements in 1969 and 1973-1974, and p and q are the coefficients of the reference ellipsoid (p is almost constant and q varies with the latitude of the station).

The horizontal component of the surface velocity V_h (m/a) is given by

V_h = delta_S * 365/N

where N is the number of days between two observations (1453 <= N <= 1514)....

Literature References:

(Also see: Related Publications)

Naruse, Renji (1978). "Studies on the Ice Sheet Flow and Local Mass Budget in Mizuho Plateau, Antarctica." Contributions from the Institute of Low Temperature Science 3--54.

Takahashi, S. (1997). "Sheet 6, Ice Sheet Dynamics". East Queen Maud Land Enderby Land: Glaciological Folio. 1--7. National Institute of Polar Research.

Data Set Access

Access the tabular velocity data for the Mizuho Plateau