Figure 2 Launching a radiosonde Macquarie Island 1968—note radar target for upper wind measurement (Photo S. Harris—Antarctic Division).

With the establishment of Mawson in 1954 (albeit with the loss of the Heard Is observations though with observations continuing by the French expedition at Kerguelen) a new window was opened with observations from the fringe of continental Antarctica (Loewe 1956, Shaw 1957, Hannan and Dingle 1958, Streten 1961, Weller 1969). However, in the earliest years the isolated Mawson observations were primarily of interest for studies of the in-situ conditions (in particular, the low level wind structure and the characteristics of blizzards rather than how they fitted into the broad pattern of Southern Hemisphere meteorology, the latter requiring observations from additional locations on the Antarctic continent. The initial studies of the local climate at Mawson (as with other individual locations in Antarctica) have been further documented over the years and constitute a useful benchmark data site for the monitoring of global climate. Figures 3 and 4 indicate some basic characteristics of the Mawson wind and severe weather regime as an example of the longer term records from Antarctic stations. The total observational record from ANARE stations and field sites was systematically published over many years and is now consolidated into a readily accessible, quality controlled computer archive held by the Bureau's National Climate Centre.

Figure 3 An example of station climatology. Some characteristics of the wind regime of Mawson (after Streten 1990). Annual variation at Mawson for indicated pressure levels expressed in hectopascals (hPa) of: (a) Mean upper wind speed (ms^-1—full lines) and direction (arrow points vertically for southerly winds and horizontally to the right for a westerly wind); (b) percentage constancy of wind direction (note change of scale between 100 and 90 hPa—28 years of data 1956–1983). Annual variation at Mawson of: (c) mean windspeed based on monthly data A—mean, B and C extremes for individual months; (d) percentage frequency of wind direction; figures at the right show monthly mean percentage of calms—30 years of data 1954–1983; (e) diurnal variation (Local times—LT) at Mawson of percentage frequency of light winds <1.4ms^-1 or 2.7 knots. Figures at the right show total frequency for all hours.

Figure 4 Meteorological conditions during a typical prolonged winter blizzard at Mawson (29 June to 6 July 1958). The lower panel shows present weather symbols and shading corresponding to visibility and cloud criteria, X indicates sky obscured by drifting snow (after Streten 1968).

The next major step in the resolution of the big picture of Southern Ocean meteorological processes came with the International Geophysical Year (IGY) of 1957–58 when a substantial network of stations was set up in Antarctica to provide extensive geophysical data and, in particular, surface and upper air meteorological observations around the continent and at the US Amundsen-Scott base at the South Pole and at the USSR base at Vostok in the interior. These stations included Davis and the US base at Wilkes (which was operated by Australia from 1959 to 1969 when it was replaced by the new Australian built station, Casey). The IGY Antarctic network data together with the observations from the circumpolar Southern Ocean islands were now available for the first time and were assembled on an operational basis at the US station Little America in the Ross Sea where an "Antarctic Weather Central" was established and a team of international meteorologists including K. Morley from Australia attempted a full hemisphere analysis. This work led to the publication of extensive international studies of southern hemisphere circulation eg. by Astapenko (1964), van Loon (1965, 1967) and Taljaard (1972). A more detailed Australian perspective of early Southern Hemisphere meteorological analysis and the contributions of many Australian synoptic meteorologists including R. H. Clarke, W. J. Gibbs, A. K. Hannay, J. C. Langford, H. M. Treloar, U. Radok and P. J. Shaw is given elsewhere (Streten 1980a).

Following the IGY a major international conference on Antarctic meteorology was held in Melbourne (Bureau of Meteorology 1960) and a continuing international analysis program was established in Melbourne at the International Antarctic Analysis Centre (IAAC) (Gibbs 1960a 1960b. This Centre operated from 1959–1966 (from 1966 to 1969 being known as the International Antarctic Meteorological Research Centre (IAMRC) under the leadership of H. R. Phillpot of the Australian Bureau of Meteorology. After 1967 its operational analysis function was taken over by the Bureau's Southern Hemisphere Analysis Centre (SHAC) and finally by the National Meteorological Centre (NMC). During their operation IAAC and IAMRC examined many aspects of Antarctic meteorology including mass and heat balance (Berson 1966) stratospheric warming (Phillpot 1969), surface temperature inversions (Phillpot and Zillman 1970) and broadscale synoptic climatology (Phillpot 1964 and 1968).

Bureau of Meteorology