Grasslands of the World.pdf - Disasters and Conflicts - UNEP

Australian grasslands 345
TABLE 9.1
Climate data for selected stations. Rainfall periods are October–March (summer ) and April–
September (winter ). Maximum temperature is the average daily maximum temperature during the
hottest month and minimum temperature is the average daily minimum temperature during the
coldest month.
Location Lat. Long.
Rainfall (mm)
Summer Winter
Temperature (°C)
Max. Min.
Evaporation
(mm)
Daly Waters 16.26°S 133.37°E 625 43 38.5 11.7 2 508
Cairns 16.89°S 145.76°E 1 567 440 31.5 17.0 2 254
Gayndah 25.66°S 151.75°E 510 196 32.4 6.9 2 035
Charleville 26.41°S 146.26°E 326 156 34.9 4.1 2 583
Narrogin 32.94°S 118.18°E 113 391 30.9 5.6 1 646
Wagga Wagga 35.16°S 147.46°E 276 309 31.2 2.7 1 830
Hamilton 37.83°S 142.06°E 268 432 25.9 4.2 1 311
SOURCE: Data from the Bureau of Meteorology Climate Averages.
(e.g. Daly Waters in Table 9.1) to strong winter dominance in the southwest
(e.g. Narrogin in Table 9.1). The total amounts and distribution reflect the
continental weather systems . Monsoonal rains fall in the extreme north
between November and March; tropical cyclones can affect most of northern
Australia during this time but they are very erratic; and trade winds provide
orographic rains to the northeast Queensland coast. In southern Australia, in
contrast, the most precipitation comes from frontal rains occurring from May
to September.
Erratic rainfall , disastrous droughts and occasional floods are a feature of
the Australian climate. When variability is expressed in terms of the mean
deviation as a percentage of the annual mean, the most reliable areas are the
northwest coast near Darwin, the southwest of Western Australia , coastal areas
in South Australia, Victoria and New South Wales, and Tasmania. Variability
increases inland, and the great bulk of Australian rangelands have highly erratic
rainfall. Maximum variability is found on the western coast near the Tropic
of Capricorn and in central Australia. Much of the variation in rainfall in
eastern Australia can be related to the ENSO (El Niño-Southern Oscillation)
phenomenon of sea surface temperatures and atmospheric pressures over the
Pacific Ocean.
Temperature and evaporation
Summers are warm to hot (Table 9.1). Maximum temperatures above 38°C are
common in inland areas and, apart from the mountains of the southeast, can
occur occasionally in other areas. Winters are warm in northern Australia and
cold in the south, with occasional snow above 600 m. Frosts occur in all regions
except the extreme north, and coastal areas in other tropical and subtropical
regions. Evaporation is lowest in the Tasmanian highlands. On the mainland,
evaporation is lowest in coastal areas and increases inland to maximum values
exceeding 3 000 mm in central Australia. The generally mild conditions make
it unnecessary to house animals during winter .