This is perhaps shown most graphically in a table:—
Name. | Height. | Rainfall. | |
Wet | New England Plateau | 3,000 ft. + | 30-40 in. |
Dry | Cassilis Geocol | 1,000-2,000 ft. | 20-30 in. |
Wet | Blue Mountain area | 3,000 ft. + | 30-40 in. |
Dry | Lake George Geocol | 2,000 ft. | 20-25 in. |
Wet | Tindery Range | 3,000-5,000 ft. | 25-30 in. |
Dry | Cooma Geocol | 2,000-3,000 ft. | Under 20 in. |
Wet | Snowy Ranges | 3,000-7,000 ft. | Over 50 in. |
Dry | Omeo Geocol | 2,000-3,000 ft. | 20-30 in. |
Wet | Barry Mountains | 3,000-5,000 ft. | Over 50 in. |
Dry | Kilmore Geocol | 1,200 ft. | 25 in. |
Wet | Ballarat Uplands | 2,000 ft. | 30 in. |
One or two other isolated areas deserve brief mention. The noticeable effect (in the far West) of the comparatively low Grampians and Cape Otway Ranges on the rainfall is very evident. The latter, though less than 2,000 feet high, lead to precipitations of over 50 and at a few stations nearly 80 inches annually. Near Geelong is one of the peculiar locally dry areas, due no doubt to its occupying a low-lying situation, sheltered from north, south, and north-west winds.
A similar occurrence of heavy rainfall (50 inches) on the insignificant Gippsland Hills (1,000-2,000 feet) seems to have robbed the atmosphere of the moisture due to the more eastern regions around Sale. The latter has 5 inches less rainfall than the rest of Eastern Victoria.
We have noticed the dry belt in the Omeo region, and the similar but, larger dry belt in the Cooma Valley (The Rift). Behind Sydney is a very interesting patch extending from Picton to the Emu Plains, with less than 30 inches. This area lies between the Blue Mountains and the highlands about Bowral and Moss Vale. The former intercept the westerly rains, the latter those coming from the south-east.
The volcanic ranges of the Warrumbungles and Nandewars also give rise to considerable increase in the rainfall in the vicinity.
Similar relations of great local importance must necessarily obtain in the other regions of the continent, but absolutely no data of the contours is available for the comparison.
VIII.—CHIEF CLIMATIC REGIONS.
Our study of the chief weather elements has shown us that Australia has not one general climate, but contains within its vast area several types of climate. They may be classified according to many factors; such as amounts of rainfall, seasons of rainfall dominant winds, topography, &c., &c. A combination of the first two criteria seems to furnish the best primary division, while the less important factors will determine the secondary subdivision.