Australias climate and vegetation Climate is the pattern

Australia’s climate and vegetation Climate is the pattern of weather that is expected in a particular place, based on the experience of the previous 30 years. It is not just the ‘average weather’ as it takes into account the extremes that can occur. Patterns of climate and vegetation are closely related because climate is the main factor that determines where plants can grow.

Australia’s pattern of climate • Australia has a wide range of climates due to its location and extent. About 40 per cent of the continent lies within the tropics—the zone between the Equator and the Tropic of Capricorn —where it is warm all year round and there are only two seasons—wet and dry. The remainder of the country lies in the temperate zone and experiences four seasons—spring, summer, autumn and winter—each with its own distinctive weather patterns.

Factors influencing Australia’s climate One of the most distinctive features of the Australian climate is its variability. There a range of factors that influence climate and are responsible for the changes that occur from region to region and from year to year. • Latitude—The Earth receives more of the Sun’s energy at the Equator than at the poles so temperatures are highest at the Equator and decrease as latitude increases. • Distance from the coast—The sea has a moderating effect so temperature ranges are less at the coast than inland. Onshore winds bring higher precipitation to coastal areas. • Ocean currents—Currents from nearer the poles bring cooler conditions and those from nearer the Equator bring warmer conditions. • Direction of prevailing winds—Winds from nearer the Equator are warmer than those from nearer the poles. Winds from over the ocean bring precipitation and those from inland are dry.

• Relief—Temperature decreases with height. Moist air that is forced to rise by mountains cools, and the water vapour condenses, producing increased cloud cover and precipitation. Highland areas are cooler and wetter than lowland areas. • Pressure systems—High pressure associated with sinking air brings dry settled weather. Low pressure caused by rising air brings unsettled weather. Australia is dominated by high pressure with low pressure in the north during summer and in the south during winter. • El Niño—The normal circulation pattern in the Pacific Ocean brings rain to Australia. In an El Niño year the circulation reverses and South America receives the rain while Australia remains dry.

Climate graphs show the average temperature and rainfall for a given place over a 12 -month period. They are used by geographers to study spatial patterns of climate and the relationships between temperature and rainfall. Each graph is composed of a column graph showing the precipitation and either one line graph showing the average temperature or two line graphs, one showing the average maximum temperature and the other showing the average minimum temperature.

Climate graph

Activity • Go to the site below and complete the Activities • http: //www. bom. gov. au Activities 1. Go to climate information and then Climate data online a) Choose either temp or rainfall b) Choose an area c) Choose a station d) Click get data e) On the spreadsheet go to the little chart icon in the last column of the spread sheet f) Use this information to create a climate graph

Pressure Patterns

Standard Symbols

Pressure patterns • http: //www. seabreeze. com. au/info/wind. asp • Cut out pictures for worksheet and paste them in your book and then using the website above describe each pressure system

Vegetation