Apart from the oceans, the greatest single body of "water" in the world is the Antarctic ice sheet. This huge southern icecap, up to 10,000 ft thick and covering an area of 4,000 million acres, has a volume of almost seven million cubic miles.
The lowest temperatures in the world occur deep in this frozen waste. One's first impression might be that the temperature at the north and south poles should be roughly similar, but a difference occurs because of the latter's altitude: the North Pole is near sea level, but the great thickness of the Antarctic ice plateau raises its upper surface high above sea level.
It is no surprise, therefore, that it was on this elevated ice sheet that the world's lowest air temperature was observed: on July 21st, 1983, at Vostok, a Russian scientific base right at the centre of the polar ice, the thermometer dropped to 89.2 Celsius.
Vostok also has another claim to fame. The layers of ice in the polar ice sheets are vast reservoirs of information about past conditions on our planet. Snow falling on the Arctic or Antarctic wastes contains impurities, and these provide a clear signature of the state of the atmosphere at the time. As the snow is transformed into ice, layer by layer corresponding to successive seasons, these foreign bodies, together with the tiny bubbles of air trapped inside the ice, provide an almost permanent record of the climatic history of the period in which they were laid down.
The climatic information is uncovered by using a hollow drilling shaft to extract a thin "pencil" of ice from a slender hole drilled deep into the icesheet, with the sample then being taken to a laboratory for study. Much of this activity in recent y ears has been at Vostok, where Russian scientists have extracted ice dating back 200,000 years from a core over 7,000 ft deep.
If icy antipodean meteorology of this kind appeals to you, you may be interested in the latest offering of the Irish Meteorological Society. Its winter season of occasional Friday evening lectures continues tonight with a talk on this topic by Dr Christoph Kleefeld of the atmospheric research group at NUI Galway. His theme is "Meteorology in Antarctica: Some Personal Reminiscences", and deals with German endeavours in this field.
The venue is the usual Theatre G32 of the Earlsfort Terrace UCD complex; admission is absolutely free and, as the MetSoc's brochures frequently entreat us: "All are welcome; why not bring a friend?"