Tide Gauges in the Antarctic and sub-Antarctic: Instrumentation and Calibration Issues from an Australian Perspective

The measurement of sea level in the Antarctic and sub-Antarctic is of particular importance for a range of fundamental studies into the role of the region in the global climate system. As such, tide gauges remain a primary measurement tool for the oceanographic and geodetic communities, requiring accurate and uninterrupted estimates of sea level from a geographically diverse array of instrumentation. This paper provides a review of the Australian contribution to sea level observation in the Antarctic and sub-Antarctic, providing a detailed account of data availability and issues surrounding instrumentation and datum control. We also present a novel technique adopted by the Australian Government Antarctic Division (AAD) to achieve an in situ calibration of a tide gauge using a novel application of a GPS equipped buoy. First results from Davis station (68° 35' S, 77° 58' E) are presented as a case study with an emphasis on quantifying error sources within the gauge system. As the International Polar Year (IPY) 2007-2008 begins and as the temporal extent of Australian Antarctic and sub-Antarctic tide gauge data approaches nearly 15 years with near continuous operation, this provides a timely contribution to assist in maximising the scientific value of data acquired under the most demanding of conditions.