Australia

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Introduction

1. Australia is a country of contrasts

2. The climate of Australia

3. The influence of climate on the environment of Australia

Conclusion

Literature

Introduction

Australia, smallest of continents of the Earth, is allocated with an exclusive originality of the nature. It is continent of relicts, ancient natural objects and unique fauna. The nature ancient of mainland has remained almost constant in conditions of long isolation from other continents and absence of a competition from "new" kinds of plants and animals, because Australia is separated from other continents by enormous oceanic spaces.

Australia is also the driest inhabited continent on earth, but the eastern seaboard where the majority of the population is concentrated, is a lush and fertile area, with a climate ranging from temperate to tropical. The main mountain range known as the Great Dividing Range or Eastern Highlands. This long mountain chain separates the green eastern seaboard from the barren Outback. The southern end of the Great Dividing Range has an area known as the Snowy Mountains, or otherwise known as the Australian Alps. This area actually receives more snow than Switzerland, and is the only area suitable for skiing in Australia. Australia also contains many pockets of tropical and temperate rain forest on the eastern coast, but the predominate forests in Australia is Eucalypti forests. The southwest corner of Western Australia has a Mediterranean climate and the Northern regions of this continent have areas of Rainforest and below that are large areas of savanna grasslands. Tasmania, the island state in the south has large areas of temperate wilderness and steep mountains.

1. Australia is a country of contrasts

Australia can be split into three parts-the eastern highlands, central lowlands, and the western plateau.

The highlands consist mainly of high plateaus and broken-in places by hills, low mountain ridges, and gorges. Grasses or forests cover most of the plateaus, but some have fertile lands for crops. The southern part is most likely the most heavily populated part in all Australia, from Brisbane to Melbourne. In the southern region lie the Australian Alps. The Murray River, Australia's only river that constantly flows from the Alps, is the longest river.

Australia's second major region, the central lowlands, is generally a flat area with infrequent rainfall along the north and south coasts and near the eastern highlands. The two large towns in the region have fewer than 30,000 people.

Australia's third major region, the western plateau, covers the western two thirds of Australia. A vast, dry, treeless plateau extends about 400 miles along the regions southern edge; while the central part is mostly desert.

The country occupies the whole continent, so the climate is different in different regions of the country.

Australian seasons are the antithesis of those in Europe and North America (because Australia is south of the Equator): summer starts in December (ends in February), autumn in March (ends in May), winter in June (ends in August) and spring in September (ends in November).Seasonal variations are not extreme and it's rare for temperatures to drop below zero on the mainland except in the mountains.

Darwin, in the far north, is in the monsoon belt, where there are just two seasons: hot and wet, and hot and dry. The southern states are popular during the summer months, but the best time to visit is probably the seasons of spring or autumn when the weather in the south is mild. Spring in the outback can be spectacular if rains encourage wildflowers.

Average annual temperatures vary from about 27 °C in the north of the continent to 13 °C in the south. Floods and cyclones are rather common along the coast of the continent.

Summer (December-February) can get uncomfortably hot just about anywhere, except Tasmania. If you are in the southern states during these months its great beach weather. Up north, this is the wet season, when it is very, very humid and when the sea abounds with box jellyfish.

From June until August things have cooled down a little and dried up a lot up north. This is a good time to visit Queensland or the outback. If you are here for the skiing, now's the time to head for the snowfields of Victoria and New South Wales.

Overall, spring and autumn are probably the safest bets -- the weather is reasonably mild wherever you are, and spring brings out the wild flowers in the outback, while autumn is particularly beautiful in Canberra and in the Victorian Alps.

2. The climate of Australia

The climate in Australia is varied and ranges from tropical to sub alpine. Australia is also the oldest landmass on earth and the most eroded of all continents, the nearby island state of Tasmania being the exception. This vast landmass is also the most stable of all continents, with few major fault lines. This means that Australia lacks high mountains such as what you find in neighboring New Zealand. However all the eons of erosion have formed some of the strangest geographical features on earth, such as Ayers Rock in the Northern Territory, or the Bungle Bungles Mountains, and The Pinnacles of Western Australia.

The island continent of Australia features a wide range of climatic zones, from the tropical regions of the north, through the arid expanses of the interior, to the temperate regions of the south. Australia is the world's second-driest continent (after Antarctica), with average (mean) annual rainfall below 600 millimeters (mm) over 80% of the continent, and below 300 mm over 50%. Summers are hot through most of the country, with average January maximum temperatures exceeding 30 degrees Celsius (°C) over most of the mainland except for the southern coastal fringe between Perth and Brisbane, and areas at high elevations. Winters are warm in the north and cooler in the south, with overnight frosts common in inland areas south of the Tropic of Capricorn. Only at higher elevations do winter temperatures approach those found in much of northern Europe or North America.

Seasonal fluctuations in both rainfall and temperature can be large in parts of the country. In northern Australia, temperatures are warm throughout the year, with a `wet' season from approximately November through to April, when almost all the rainfall occurs, and a `dry' season from May to October. Further south, temperature becomes more important in defining seasonal differences and rainfall is more evenly distributed throughout the year, reaching a marked winter peak in the south-west and along parts of the southern fringe.

Australia's climate is largely determined by its latitude, with the mainland lying between 10 degrees south (°S) and 39°S and Tasmania extending south to 44°S. This places much of Australia under the influence of the sub-tropical high-pressure belt (or ridge), which is a major influence on climate near, and poleward of, the tropics in both hemispheres. The aridity of much of Australia is largely a consequence of the subsiding air associated with this ridge of high pressure.

Because Australia is in the southern hemisphere, the seasons are opposite to those in Europe and North America. Australia is often referred to as a land of diversity in terms of climate: from tropical rainforests, to golden beaches, to sparse deserts, to vast grazing lands to the rich coral reef, bursting with marine life.

The weather in Australia can range from the below zero temperatures of the Snowy Mountains region to the extreme heat of the northwest.

Australia experiences many of nature's more extreme weather phenomena, including droughts, floods, tropical cyclones, severe storms, bushfires and the occasional tornado.

The northern third of the Australian continent lies in the tropics and is warm or hot year round. The rest of the country lies south of the tropics and has warm summers and mild cool winters. The rainfall is seasonal in Australia.

Tropical cyclones bring heavy rain as well as strong winds, and are the cause of most of Australia's highest-recorded daily rainfalls. Warm water acts as the cyclone's energy source, and hence is required to maintain the strength of the winds. As a result, tropical cyclones rapidly lose their intensity on moving over land, although the rainfall with former cyclones often persists well after the destructive winds have eased. This occasionally brings heavy rains deep into the inland, causing widespread flooding; such flooding can also occur from tropical depressions that never reach sufficient intensity to be classified as cyclones. Parts of inland Western Australia receive 30% to 40% of their average annual rainfall from these systems, and it is not unknown for places to receive their average annual rainfall within a one or two-day period as a tropical cyclone (or ex-cyclone) passes by.

On average, about three tropical cyclones directly approach the Queensland coast during the season between November and May, and three affect the north and north-west coasts, but the number and location of cyclones varies greatly from year to year. While the most susceptible areas are north of Carnarvon on the west coast and north of Rockhampton on the east coast, on occasions tropical cyclones have reached as far south as Perth and northern New South Wales. The most intense cyclones are most common off the north-west coast, but can also occur off the northern and eastern coasts. Tropical Cyclone Monica, in April 2006, was the most intense cyclone ever recorded off the Northern Territory coast, while Yasi, in February 2011, was the most intense cyclone to make landfall in Queensland since at least 1918.

Away from the tropics, 'heatwaves' can occur over many parts of Australia. In southern Australia, they are normally associated with slow-moving anti-cyclones. A large anti-cyclone remaining stationary ('blocking') over the Tasman Sea will result in northerly or north-westerly flow on its western flank, bringing hot air from the center of the continent over the south-east coastal regions (and sometimes to Tasmania). In south-western Australia, summer heatwaves are more commonly associated with the characteristic north-south trough of low pressure along the west coast moving offshore, suppressing sea breezes and causing hot north-easterly winds to blow from the interior to the coast.

'Cold outbreaks' can occur over southern Australia when intense south to south-west flow associated with strong cold fronts or large depressions directs cold air from the Southern Ocean over the continent. These outbreaks are most common in the south-east of the country and can result in low temperatures and snow falling to low elevations. While principally a winter and early spring phenomenon, cold outbreaks can occur at other times of year, and the fact that the air originates over the Southern Ocean (where there is only about a 4°C change in temperature from winter to summer) means that they can also bring cold air and 'unseasonable' snowfalls at high elevations at any time of year.

Intense low-pressure systems can also form outside the tropics, most commonly off the east coast where they are known as 'east coast lows'. These systems can bring very strong winds and heavy rain, particularly where they direct moist easterly winds on their southern flank onto the coastal ranges of southern Queensland, New South Wales, eastern Victoria and north-eastern Tasmania.

Heavy rainfall conducive to widespread flooding can occur anywhere in Australia, but is most common in the north and in the eastern coastal areas.

Thunderstorms are most frequent over northern Australia. Thunder is heard at least once on 80 days or more per year near Darwin, largely as a result of convectional processes during the summer wet season. High frequencies (30 to 50 per year) also occur over the eastern uplands of New South Wales as a result of orographic uplift of moist air streams.

Thunderstorms are also relatively common over many parts of inland Australia, with most of the arid zone having at least 15 thunder days per year, and parts of interior Western Australia having 40 or more. These storms are often `dry' with most or all rain evaporating before it reaches the ground - indeed, in a few locations there are more days of thunder per year than there are days of rain.

Tornadoes are also associated with severe thunderstorms, although they do not occur with the same frequency or severity as can occur in the United States of America. As tornado paths are narrow, it is rare, but not unknown, for them to strike major population centers.

The climate of Australia can vary a great deal from place to place, although in summer it is basically hot everywhere in varying degrees (little weather joke there).

The dry climate of Australia, especially in the northern region leads to droughts, heat waves and bushfires. Bushfires are a major cause of concern in Australia.

Drought, in general terms, refers to an acute deficit of water supply to meet a specified demand. The best single measure of water availability in Australia is rainfall, although factors such as evaporation and soil moisture are also significant and can be dominant in some situations. Demands for water are very diverse, and droughts therefore can be considered on a variety of timescales. Rainfall in a single year is important for unirrigated crop and pasture growth, while for large water storages and irrigation, variations on a multi-year timescale are more important, and a succession of relatively dry years that are not exceptional individually can cause severe water storages when aggregated over an extended period.

Sunshine here refers to bright or direct sunshine. Australia receives relatively large amounts of sunshine, although seasonal cloud formations affect spatial and temporal distribution. Cloud cover reduces both incoming solar radiation and outgoing radiation from the earth's surface, and thus affects sunshine, air temperature and other measures of climate.

In southern Australia, the duration of sunshine is greatest about December when the sun is at its highest elevation, and lowest in June when the sun is lowest. In northern Australia, sunshine is generally greatest over the period August to October prior to the wet season, and least over the period January to March during the wet season.

australia climate cyclone park

3. The influence of climate on the environment of Australia

Australia has 20,000 species of plants and brilliant wildflowers such as the red and green kangaroo paw.

The continent has many species of acacia, which Australians call wattle, and 1,200 species eucalypti or gum trees.

Many of the trees lose their bark not their leaves and a lot of flowers have no smell. The gum, found across the continent, ranges from 90 m high to stunted types in arid zones. One eucalyptus, the Jarrah, ranks among the world's hardest woods. The tropical north east belt with its heavy rainfall and high temperatures is heavily forested.

Although predominantly evergreen, vegetation ranges from the dense bush land of the coast to the mulga and mallee scrub of inland plains.

Palms, ferns, and vines grow prolifically among the oaks, ashes, cedars, and beeches. Along the eastern coast and in Tasmania are found forests of pine, which rank second to the eucalyptus in economic importance. The wild flowers of the region are varied and spectacular. In the less dense regions of the interior slopes there are red and green Kangaroo Paws, scented Boronia, Wax Flowers, and Bottlebrushes.

In the interior region of low rainfall, characteristic plants are saltbush and grass, which provide fodder for sheep, and mallee2 and mulga3 scrubs. The most valuable native grass including Flinders grass, are found in Queensland and New South Wales. During occasional flooding rapid and luxuriant growth of native grasses and desert wild flowers occurs, and water lilies dot the streams and lagoons. Australian states and territories have their own floral emblems: the common pink heath is the emblem of Victoria, Waratah is the emblem of New South Wales, Cooktown Orchid is the emblem of Queensland, Sturts desert pea is the emblem of South Australia, Southern Blue Gum is the emblem of Tasmania, Sturts Desert Rose is the emblem of Northern Territory, Red and Green Kangaroo Paw is the emblem of Western Australia.

There are many national parks in Australia, among them Lichfield National Park where one can observe Australian plants and animals. Plants and animals have evolved on a geographically isolated continent, through a time of a slowly drying climate, combined with continuing high variability. The uniqueness of much of Australia's flora and fauna is thus at least partly due to these features of our climate.

In the southern region farmers grow wheat but most of the region is to hot or to dry for crops. However, the course grass or shrubs that cover the land make it suitable for livestock.

A lot of the desert area consists of swirling sands that often drift into giant dunes. In places the desert gives way to land covered by grass and shrubs. Grazing livestock can then use the land. The north and south has the regions heaviest rainfall. The regions two largest cities are Adelaide and Perth.

The bush, as the Australians call it, refers to the countryside. The term outback refers specifically to the interior of the country, with is mainly open countryside including vast expanses of grazing land. About 13 percent of Australia's people live in these rural areas. Many people live extremely isolated lives on sheep and cattle ranches called stations. Some of the largest stations cover more than 1,000 square miles from the nearest town.

Outback animal life is varied and includes native species such as kangaroos, wallabies, and emus, and introduced species, such as rabbits. The large size of agricultural stations makes it prohibited to fence off crops from wildlife. Some animals have caused extensive damage to crops and grazing lands. Wild rabbits especially have been destructive. Recently rabbits have been targeted in a drive to wipe them out with a deliberately introduced disease.

The outback has few paved roads so travel by car is difficult or impossible. Floods sometimes close roads for weeks at a time. Most wealthy farm families own a light airplane, which they use to travel to town. Other families get to town only a few times a year making it difficult to maintain necessities.

The largest settlements in rural Australia are widely spread towns that have developed to support mining towns. For example, Kalgoorie, a town in Western Australia, is the center of Australia's major gold and nickel fields. The town is in the arid region about 375 miles away from Perth and water must be pumped there.

All rural areas in the outback are subject to floods, droughts, and brush fires. Because they share the constant threat of disaster, the Australian communities have developed strong ties with each other. Many towns have their own traditional fairs, festivals, and sport competitions.

Droughts are most economically damaging in south-eastern Australia (southern Queensland, New South Wales, Victoria, Tasmania and the settled parts of South Australia), an area encompassing about 75% of Australia's population and much of its agriculture.

While bushfires are not strictly a climatic phenomenon, both weather and climate are strong determinants of their occurrence and intensity. Provided vegetation is sufficiently abundant and dry, the spread of bushfires is most rapid in windy conditions with low humidity. In southern Australia, such conditions are also normally associated with high temperatures. A Fire Danger Index, which combines expected wind speed, humidity, temperature and a measure of vegetation dryness, is frequently used to assess the risk of rapid fire spread on any given day.

Conclusion