Page:Types of Australian weather.djvu/39

Rh marks their centres, and the rains come chiefly from the low pressures between each pair of anticyclones, and the strong westerly gales are but part of the circulation about these high pressures. (See Charts 29 and 30.)

The one selected for illustration occupied the whole of Australia on June 4th, 1895, Chart 36. Its form was remarkably symmetrical, and in the central area the barometers read 30•6, which is somewhat unusual, hence the circulation is active, and in northern Australia where the trade wind adds force, it is very strong. Under the central influence of these great anticyclones the whole of Australia enjoys fine weather.

TYPE XIX.—SQUARE HEADED &Lambda; DEPRESSION.

This type is a variation of the usual &Lambda; depression, but is sufficiently characteristic to be placed by itself as a type or rather a sub-type. Its isobaric peculiarity, as may be seen by reference to Charts 37 and 38, is that there is a flat top or square head to the isobars of the &Lambda;, the usual form of which is a sharp and regular curve, and the marked feature of this is that under it the weather is remarkably squally and charged with thunder