The climate of Macquarie Island and its role in atmospheric monitoring

Abstract

An analysis is made of the principal climatic elements at Macquarie Island in relation to the general circulation of the high latitudes of the southern hemisphere. The climate is characterised by a high frequency of strong west to northwesterly winds and frequent gales, low variability of temperature, a high frequency of low cloud and fog, and a high number of days with precipitation throughout the year. In general, the climate is typical of a higher mid-latitude oceanic island, and its features are compared with others in the circumpolar Southern Ocean. From a different perspective the island occupies a unique geographic site. This makes it extremely valuable as a meteorological observatory, enabling regular surface and upper air observations for day-to-day global analysis and forecasting, and providing climatic data representative of the higher southern mid-latitudes. Despite the advent of new observational techniques (such as satellite-reporting drifting ocean buoys, satellite cloud imagery and satellite-derived atmospheric temperature profiles), the observations from Macquarie Island conttnue to constitute essential calibration data for space-derived measurements and provide the long-term continuity only possible at a fixed baseline station. The importance of these data is stressed; not only with respect to the standard meteorological observations but also to the measurement of ozone, carbon dioxide and other atmospheric trace constituents which are becoming increasingly recognised as significant in studies of long-term climatic change.