Aurora Australis Voyage 1 (IDIOTS) 1999-00 Underway Data

This dataset contains the underway data collected during the Aurora Australis Voyage 1 1999-00 (IDIOTS). This was a dedicated marine science cruise researching winter-time oceanographic, glaciological, meteorological and biological processes within a polynya off the Mertz Glacier at about 145 degrees East. Underway (meteorological, fluorometer, thermosalinograph and bathymetry) data are available online via the Australian Antarctic Division Data Centre web page (or via the provided URL). For further information, see the various reports at the Related URL section. From the Voyage Leader's Report:Voyage 1 of RSV Aurora Australis for the 1990/00 season was an 8-week scientific cruise to the wintertime pack ice south of Australia. The voyage left Hobart on July 13 for instrument calibration at Port Arthur, then headed for Antarctic waters on 16 July. The vessel spent nearly 6 weeks within the sea ice zone, investigating oceanographic and glaciological processes that are related to global climate, and undertaking a range of biological studies before returning to Hobart on 7 September 1999.The purpose of the voyage was an investigation of the Mertz Glacier Polynya (MGP), centred near 66.5 S, 145 E and with an area of about 20,000 square kilometres. Polynas are areas of anomalous open water and thin ice in regions that are otherwise covered by pack ice. Paradoxically, although these areas are relatively ice free, they are areas of very high ice production. When open water occurs near Antarctica in winter, the loss of heat from the ocean to the cold polar atmosphere is enormous, and ice production is consequently very rapid. Salt is rejected from the growing ice into the underlying ocean, increasing its density, and these processes within polynyas are potentially a vital first step in the formation of the cold, dense Antarctic Bottom Water. The MGP is one of the largest persistent winter polynyas on the Antarctic coast and has been linked to the formation of "Adelie Bottom Water". Because polynyas provide access between the surface and the ocean for larger animals, and because they allow pentration of solar radiation into the water column in springtime, they may also be important biologically. If nutrients are adequate they can act as biological oases.Voyage 1 1999/00 was the second attempt at this study: in July 1998 a study of the MGP was aborted following a major engine room fire on Aurora Australis. Although it was not the first research cruise to the Antarctic pack ice in winter (there have been several in other parts of Antarctica, and one earlier ANARE expedition to the more northerly pack ice south of Australia in 1995) V1 1999/00 was the first time that a vessel has worked within a polynya right on the Antarctic coast during winter.Voyage 1 1999/00 was completely successful and achieved almost all its measurement objectives. A vast amount of data was collected during the 40 days within the pack, and details of many of these data are given in the appendices to this report.