The Movement of Halley; 1956 - 2016

Andy Smith


Introduction

The diagrams below were shown at Z60, the reunion held to celebrate the 60th anniversary of the founding of what later became Halley Research station. It was suggested to me by Malcolm Guyatt (Halley GA 1969-1970) that it would be of interest to plot how each of the six bases, occupied over the 60 years, had moved horizontally as they were transported by the Brunt Ice Shelf. Peter Kirsch (BAS Data Manager) collected data from various sources in BAS. These consisted of the geographic latitude and longitude of the base at each of a number of dates between 18 May 1957 for Halley I and 8 August 2016 for Halley VI. The early data were mostly from astronomical observations (star shots, sun shots) whilst data from the later years were from GPS measurements. The data are shown by dots in the first figure, colour coded differently for each of the six bases (Z1 - Z6). Because the data, especially the early data, are scattered, presumably due to measurement errors, I have assumed that the horizontal velocity is constant in magnitude and direction for the lifetime of the base, represented by a best-fit straight line through the data points. Annually spaced time marks are shown along the line between 1 January of the first year of occupation of the base, as shown on the Six Bases page, to 1 January of the year following the last year of occupation (1 Jan 2017 in the case of Halley VI).

The second figure below is the same except that a larger area is shown so that the proposed site of the relocated Halley VI (ZVIA) can be shown.

Figures

(Click on the diagram for a larger version)

(Click on the diagram for a larger version)

Discussion

All the velocities are in approximately a westerly direction. For Halley I to Halley IV the directions are a few degrees north of west whereas the opposit is the case for Halley V and Halley VI. As far as magnitudes are concerned, the speed increases from ~400 m/yr to ~800 m/yr between Z2 and Z3, while at Z6, the speed is back to about 400 m/yr. Quantitatively:

BaseSpeedDirection
Halley-I393 m/yr264
Halley-II379 m/yr262
Halley-III822 m/yr265
Halley-IV738 m/yr268
Halley-V673 m/yr271
Halley-VI433 m/yr277

The Halley V data should be treated with caution as it is believed that some of the GPS data may be suspect due to not resetting.

The results are in agreement with previously published velocities of 36640 m/yr; 2665 for Halley-I (Limbert, 1964), 7409 m/yr for Halley-III (Simmons and Rouse, 1984) and 7426 m/yr; 266 for Halley-IV (Simmons and Lurcock, 1988).

References

Limbert D.W.S., The Absolute and Relative Movement and Regime of the Brunt Ice Self near Halley Bay, BAS Bulletin No. 3, p1-11, May 1964
Simmons D.A. and Rouse J.R., Accelerating flow of the Brunt Ice Shelf, Antarctica, J Glaciology 30, p377-380, 1984
Simmons D.A. and Lurcock P.M., The Movement of Halley derived from Satnav Measurements 1986 -1987, BAS Bulletin No. 78, p55-57, Feb 1988


16 November 2016
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