Figure 10 Antarctic surface observation network in 1996 indicating stations which report in near real time via the Global Telecommunications System (GTS) of the World Meteorological Organization (WMO). Staffed stations are shown by full circles and Automatic Weather Stations by open circles (source—WMO).

Figure 11 The routes by which Antarctic meteorological data enter the Global Telecommunication System (GTS) (source—WMO).

Automatic Weather Stations (AWS) have improved vastly in design and reliability in recent years. Australia was among the first to experiment with AWS in Antarctica. Between 1959 and 1961 AWS were installed at Lewis Island and Chick Island; however these experiments were ahead of their time and were in general not successful. The quite massive installation of wind generator, building and aerials at Chick Is (Figure 12) may be contrasted with a modern AWS (see eg Figure 13). Modern AWS are solar or wind powered, report directly via satellites and are now increasingly becoming a principal feature of the Antarctic observing network. In particular meteorological data are progressively being obtained from the new network of Automatic Geophysical Observatories (AGOs) which have been deployed largely by the US and UK over the otherwise vast data void area of the high Antarctic plateau. While the AGO observations are essentially designed to measure specific non meteorological geophysical data they are also being instrumented to provide the basic meteorological pressure and temperature data which are necessary for numerical weather analysis. Some Antarctic AWS provide more detailed information for research purposes in non real time (Stearns and Wendler 1988) but the intention is to have as many as possible of such research installations equipped to provide basic real time information to the GTS for day to day analysis. Surface pressure and temperature observations from the high level ice cap can be utilised in building up an assessment of the height of the standard pressure surfaces (eg 500 h Pa) using statistical techniques (Phillpot 1991).

Figure 13 A typical modern Automatic Weather Station being installed at Haupt Nunataks SSW of Casey—note solar cell panel (photo—Adrian Porter, Bureau of Meteorology).

Figure 12 Installation of Chick Island Automatic Weather Station by ANARE 1961 (photo—Antarctic Division).

Similarly, the drifting buoys which have been progressively deployed in the oceans since FGGE and more recently (under the International Program for Antarctic Buoys—IPAB) within the sea ice zone have the capacity to transmit basic meteorological information and sea surface temperature data as well as identify their locations. Efforts are being made to improve the coverage and Australia is contributing significantly.

The current suite of meteorological satellites which provide data for global operations and research are shown schematically in Figure 14 though further developments include substantial improvements to the Russian satellite transmissions and the imminent dissemination in Australia of the data from the Chinese geostationary satellite Feng Yun (FY2). Most significant for polar research are the US NOAA (National Oceanic and Atmospheric Administration) polar orbiters which continue to provide high resolution imagery and vertical sounding (TOVS) (TIROS Operational Vertical Sounder) data over the polar regions. TOVS data provide measurements similar to but not as precise as those from radiosondes along the track of the satellite over cloud-free ocean surfaces. In addition, cloud drift wind vectors can be calculated (see eg Figure 15) using the data from the geostationary satellites, in particular the Japanese Geostationary Meteorological Satellite (GMS) positioned over the equator at 140°E and continuously viewing the longtitudes of the Australian region. GMS and the other geostationary satellites are not able to view very high latitudes but provide useful coverage of most of the Southern Ocean. More recently data are becoming available from the microwave scatterometer on board the European Earth Resources Satellite (ERS 1) which provide measurements of wind vectors at the sea surface. There are indications that such observations will prove useful in operational Southern Ocean analysis (Figure 16).

Figure 14 Space based Global Observing System of operational meteorological satellites. The longitudes of the five geostationary satellites above the equator are indicated as are the polar orbits of the US NOAA and Russian Meteor Series (source—WMO).

Figure 15 Upper wind vectors derived from cloud drift shown against the background of infra red imagery for the Japanese Geostationary Satellite (GMS) at 0330 UTC on 27 October 1996. Winds at 900 (green), 700 (yellow) and 400 (red) hPa are indicated. Winds are depicted as arrows flying with the wind with speeds shown in knots—triangular barb represents 50 knots full feather 10 knots, half feather 5 knots (source Steve Pendlebury—Bureau of Meteorology).

Figure 16 Microwave scatterometer data from the European Earth Resources Satellite (ERS 1) indicating wind direction at the sea surface at 05 UTC 1 January 1995 (upper panel) and the effect of its incorporation into the analysis of the Southern Ocean (middle panel—original analysis, bottom panel, with scatterometer data included). Note the more accurate specification of the deep low pressure near the Antarctic coast (source—Kieran Jacka—Bureau of Meteorology).

Bureau of Meteorology