Australia, to judge by Neighbours, Home and Away and the present Olympian coverage of Sydney, would appear to be a pleasant little spot. For the meteorologist, however, the antipodes can be confusing; all the familiar, comfortable concepts of the weather are turned upon their heads.
One can cope with the fact the seasons are reversed: Christmas comes in the middle of summer, and what passes for winter in Australia seems to happen in July and August. But more than that, the whole pattern of the weather in the southern hemisphere is very different in character from that familiar here.
In the northern hemisphere the smooth westerly flow of air around the world is disrupted by a number of large mountain ranges - by the Rockies, the Alps and the Himalayas. They cause the streaming atmosphere aloft to undulate, and this in turn results in more disturbed conditions near the ground. Comparable barriers south of the Equator are fewer and less obstructive, so the air circumnavigates the globe in a smoother and more orderly way. This uniform motion manifests itself in the "roaring forties" - a band of surprisingly persistent winds which run like a ribbon around the globe from west to east in the middle southern latitudes.
There are anti-podean peculiarities which strike the northerner as even stranger. For example, although Australia itself looks perfectly normal on the weather map, all the weather systems are reversed.
Buys Ballot's law, as it applies in the northern hemisphere, states that if you stand with your back to the wind, the low pressure is to your left. This translated on to the weather map means that the wind blows in an anti-clockwise direction around centres of low pressure, and clockwise around anti-cyclones. In the southern hemisphere, however, everything is reversed; the wind blows clockwise around depressions, and anti-clockwise around areas of high pressure.
Moreover, the familiar weather map in the daily newspaper in this part of the world shows the main frontal activity to the south of each area of low pressure. The typical mid-latitude depression has a triangular wedge of warm air embedded in it - a wedge with its apex at the centre of the depression, and pointing towards the north. This wedge is what meteorologists call the warm sector, bounded by a warm front at its leading edge and a cold front following up in the rear.
But in Australia they do things differently. The warm sector is on the northern edge of the depression, and the warm and cold fronts are swept clockwise around its centre.