Page:Hunt - The climate and weather of Australia - 1913.djvu/34

Rh Here also data are very incomplete except for 1910, but the main features can be deduced from a study of the tracks of the disturbances in that year. Australian weather is controlled by three belts of atmospheric eddies. In the north moving (generally) from west to east, along the Tropic of Capricorn, is a procession of low pressure systems which are usually termed monsoonal lows. (The term "Tropical" might be less ambiguous, for in winter, at any rate, there is little akin to monsoonal conditions in Australian low-pressure areas.)

South of latitude 40° is another series of cyclonic eddies probably secondaries strung along the great low-pressure belt of the Southern Ocean. These are called antarctic cyclones. Between the two lies the belt of anticyclones whose path, as we shall see, swings between latitude 30° and 42°, as the sun moves south and back again. The general tracks of the disturbances are shown on the diagrams, Figs. 32—35 (for 1910), when three facts may be noted in their characteristics. The tropical belt is much more irregular, the paths being often recurved. This series is never well developed in winter, the months of April, May, June, July, and August being generally free from these disturbances.