Antarctic Geodesy Field Report 2006-2007 - N Brown and A Woods

Brief description

Taken from sections of the report:

In recent years, Geoscience Australia (GA) has increased its capability on the Antarctic continent with the installation of Continuous Global Positioning System (CGPS) sites in the Prince Charles Mountains and Grove Mountains. Over the course of the 2006/07 Antarctic summer, Alex Woods and Nick Brown from Geoscience Australia (GA) collaborated with Dan Zwartz of the Australian National University (ANU) to install new CGPS sites at the Bunger Hills and Richardson Lake and perform maintenance of the CGPS sites at the Grove Mountains, Wilson Bluff, Daltons Corner and Beaver Lake.

The primary aim of the CGPS sites is to provide a reference frame for Antarctica, which is used to determine the long-term movement of the Antarctic plate. Data from Casey, Mawson and Davis is supplied to the International GPS Service (IGS) and in turn used in the derivation of the International Terrestrial Reference Frame (ITRF). The sites also open up opportunities for research into post-glacial rebound and plate tectonics.

In many respects CGPS sites in Antarctica are still in their infancy. Since the mid 1990's Geoscience Australia and the Australian National University have been testing new technology and various methods to determine the most effective way of running a CGPS site in Antarctica.

A more detailed review of Australia's involvement in Antarctic GPS work can be found in (Corvino, 2004)

In addition, a reconnaissance survey was undertaken at Syowa Station to determine whether a local tie survey could be performed on the Syowa VLBI antenna in the future. Upgrades were made to the Davis and Mawson CGPS stations and geodetic survey tasks such as reference mark surveys, tide gauge benchmark levelling and GPS surveys were performed at both Davis and Mawson stations. In addition, work requested by Geoscience Australia's Nuclear Monitoring Project, the Australian Government Antarctic Division (AGAD) and the University of Tasmania (UTAS) were completed.

The 2006/07 Geoscience Australia Antarctic expedition proved to be one of the most successful Antarctic seasons by geodetic surveyors from Geoscience Australia. All intended field locations were visited and all work tasks were completed.

Background
The primary aim of the CGPS sites is to provide a reference frame for Antarctica, which is used to determine the long-term movement of the Antarctic plate. Data from Casey, Mawson and Davis is supplied to the International GPS Service (IGS) and in turn used in the derivation of the International Terrestrial Reference Frame (ITRF). The sites also open up opportunities for research into post-glacial rebound and plate tectonics.

In many respects CGPS sites in Antarctica are still in their infancy. Since the mid 1990's Geoscience Australia and the Australian National University have been testing new technology and various methods to determine the most effective way of running a CGPS site in Antarctica.

Dr John Gibson from The University of Tasmania requested that Alex Woods and Nick Brown collect moss samples from any locations visited during the Antarctic summer field season. While working in the field only a few moss specimens were found. No moss or lichen specimens were observed at locations such as Wilson Bluff, Dalton Corner, Beaver Lake or the Grove Mountains. Moss samples were collected at Richardson Lake and Mawson Station and these samples were frozen after collection and returned to Australia.

This work contributed towards AAS (ASAC) project 1159.

Lineage

Progress Code: completed

Statement: See the report for further information. The values provided in spatial coverage are approximate only.

Prior to departure, Nick Brown and Alex Woods met with Henk Brolsma from the Mapping Group at the Australian Antarctic Division, who listed several survey tasks to be undertaken, on behalf of the mapping group, while in Antarctica. Most of the work was completed, including lake level surveys in the Vestfold Hills, determination of the height of a new barometer at the Davis skiway for the bureau of meteorology and surveys of the infrastructure developments at Davis and Mawson station.

A number of the requested survey tasks were not performed for a variety of reasons. The tide gauge at Davis was not calibrated as the sea ice was gone on arrival to station making it difficult to setup a GPS over the water. In addition, the tide gauges at Davis and Mawson were not downloaded as the Mawson tide gauge was already downloaded by a scientist named Kym Newbery and the wintering scientist at Davis, David Correll, intended on downloading the Davis tide gauge when the sea ice had reformed. Observation of ground control features, using GPS, at deep field location was not performed due to time constraints and weight limits on aircraft preventing the transport of personnel and equipment. Further, technical difficulties were encountered with the Thales kinematic GPS unit which prevented its operation in the cold. The malfunctions noticed with the kinematic GPS unit will be reported to Thales and investigated further.