Daily readings of total column ozone over Macquarie Island 1957-2025

This dataset was originally set up as a "State of the Environment" indicator - however, that application no longer functions at the Australian Antarctic Data Centre, so the data have been extracted and attached to this original metadata record for the indicator.These data are a locally held AADC copy of data from the WOUDC (updated periodically). It is recommended that users go to the WOUDC to ensure they have the latest copy of the data.INDICATOR DEFINITIONThe monthly means of total column ozone measured at Macquarie Island.RATIONALE FOR INDICATOR SELECTIONOzone filters ultra-violet (UV) radiation from the Sun and affects the dynamics of the stratosphere and overall atmospheric radiation balance. With reduction in stratospheric ozone levels, UV incidence on the surface has serious ramifications for Antarctic and Southern Ocean biological systems.DESIGN AND STRATEGY FOR INDICATOR MONITORING PROGRAMSpatial Scale: Macquarie Island (latitude 54 deg 29' 59"S, longitude 158 deg 57' 08"E).Measurement Technique: Global-scale daily analyses are produced by the Bureau of Meteorology on a 2.5 - degree latitude by 2.5 - degree longitude grid, using satellite data. In-situ Dobson spectrophotometer measurements at Macquarie Island in conjunction with major centres in Australia provide benchmark and calibration data of total-column ozone.Macquarie Island is the only station situated under the Antarctic Ozone hole, providing an important contribution to ozone monitoring activities.RESEARCH ISSUESThe traceable data set may be extended back a few years before 1978 but cannot go much further back with any confidence.When Dobson measurements began seriously in 1955, there was no traceability of instrument standards. Each instrument was calibrated absolutely rather than by the hierarchy of standards, beginning in 1978. In the initial measurement program, ozone measurements were used mainly for day-to-day variations - the idea of using Dobsons for a long-term trend in ozone was not an objective. Consequently the need for properly referenced instruments was not a high priority. The difficult mechanism of applying standards was not in place when measurements started in 1956.