A new estimate of the adopted gravity value at Rothera Station, Antarctic Peninsula

Extract

Because of the lack of a definitive air link to an international gravity base station, the Antarctic Peninsula gravity network was originally, and still is, tied to the Potsdam gravity system via long ship links to South America (Renner 1981, Kennett 1965). An indirect link from the British Antarctic Survey (BAS) scientific station at Rothera to an International Gravity Standardisation Net 1971 (IGSN 71) base station in the UK had previously been made via a link to the BAS gravity station on the Falkland Islands in Port Stanley (McGibbon 1988). Whilst the apparent gravity difference between Port Stanley and the base station in the UK had been calculated via a two-way air tie using a LaCoste and Romberg meter (McGibbon 1988) and later strengthened with three two-way air ties using four LaCoste and Romberg meters (Bassett 1987), the link between Port Stanley and Rothera was based on a one-way tie that included a lengthy ship borne passage (McGibbon 1988). The weakness of this link insured that the adopted gravity value at Rothera continued to be based on the ship ties made by Griffiths et al. (1964) and Kennett (1965). This note describes the strengthening of the gravity link between Rothera and Port Stanley and the subsequent reassignment of the adopted gravity value at Rothera Station.