Climate. Inland Waters of Australia

Climate. Australia lies close to the Equator in the north and is crossed by the Tropic of Capricorn in the centre. Its northern half lies within the torrid zone, its southern half and Tasmania within the temperate zone.

As seen from the climate map, the average January temperature in summer is 30° C above zero in the northern part of Australia and 20° C above zero in the southern part. The average July temperature in winter is 20° C above zero in the north and 10° C above zero in the south. Frosts occur at night even in the continent's interior which lies in the torrid zone, for in the clear air the surface of the ground is cooled rapidly. High in the mountains there is frost and snow in winter.

Rain is irregularly distributed. In the north of Australia monsoon winds blowing from the Indian Ocean cause heavy rains to fall. As they blow over the hot interior, they are heated still more, and little rain falls. The south-eastern trades blowing from the Pacific cause heavy rain on the east coast, especially on the slopes of the Great Dividing Range and other mountains. The interior of the continent is thus very hot and dry. The extreme south-west and south receive rain mainly in winter, when the western winds are blowing from the Indian Ocean.
Droughts are frequent in Australia. They are very harmful to the crops and destroy many million head of livestock. Prolonged droughts are often followed by heavy downpours that cause great floods.
The middle course of the Murray

Qlie climate depends on the temperature and rainfall. Four climatic regions may be distinguished: 1) the tropical north and north-east, where temperatures are high throughout the year and abundant rain is brought by the summer monsoon winds; 2) the wet subtropical south-east where, too, rain falls mainly in the summer, but where there is a considerable difference between summer and winter temperatures; 3) the subtropical south-west with its wet summers and dry winters, like in the Mediterranean regions of Europe; 4) the dry interior andwest of thecontinent, where the annual rainfall is under 300 mm and the daily range of temperature great (frosty nights follow hot days).
Inland Waters. Owing to the dry ness of the climate there are very few rivers in Australia. The chief river is the Murray, navigable along the greater part of its course (Fig. 190). The D a r-1 i n g, a tributary of the Murray, is a long but shallow river. During the dry season its current stops and it breaks up into a number of lakelets. Both rivers rise in the mountains in the damp east and flow into the Indian Ocean.
The interior of Australia (60 per cent of its territory) has no drainage. The temporary rivers, or creeks, as they are called, fill and even flood, but only after rains. The rest of the time they are dry.
There are many salt lakes in the interior. These are usually dry and crusted with salt. The largest is Lake Eyre, 12 metres

below sea level. It is fed by creeks that bring much water after downpours. At such times it rises violently. In the dry season, however, it grows shallow again and divides into pools.
The central, arid part of Australia west of the Great Dividing Range is very rich in underground water that drains through from wetter areas. Deep artesian wells are sunk here, in which the water rises by hydrostatic pressure.
Questions and Assignments.