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

Full description

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 DEFINITION
The monthly means of total column ozone measured at Macquarie Island.

RATIONALE FOR INDICATOR SELECTION
Ozone 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 PROGRAM
Spatial 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 ISSUES
The 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.

Lineage

Progress Code: completed

Statement: Because stratospheric ozone at any time is determined largely by meteorological transport forcing conditions (rather than by chemistry constraints), this indicator is expected to have substantial interannual variability, and care is needed in its interpretation. Trends in ozone will be analysed for signs of the success of the Montreal Protocol in phasing out ozone depleting substances (ODSs). However, the life-time of ODSs in the atmosphere is in the order of decades, and so the global concentration of ozone is expected to continue to fall until after the turn of the 20th century. Full recovery of the ozone layer will require some decades beyond the time that the supply and emission of ODSs is stopped (Fraser 1997). Values provided in temporal coverage are approximate only.