Natural Hazards affecting Australian Communities
Cyclones
Geography
Tables of contents-
Contents of page Page number
Title
1
Table of contents
2
Q1, Q2, Q3
3
Q4, Q5
4
Q6
5
Bibliography
6
Stimulus material
7
Stimulus material
8
Natural hazards affecting Australian communities- Cyclones
Q1.identify the type of natural hazard you have selected.
The natural hazard that I have selected is Cyclone also known as Hurricanes in the USA and typhoon in Asia.
Q2. Describe in detail the physical geographical process associated with the hazard.
Firstly in order for a cyclone to happen you will need very specific requirements including:
Sustained wind speeds of more than 120 km/h surrounding the centre
Very low atmospheric pressure system and
Increase sea level, storm surge and wave heights
Also most cyclones will have:
Eye diameters of 40 km on average
Eye wall marks the strongest wind and heaviest rainfall and
Spiral rain band clouds that extend over 1000 km from the eye
A cyclone needs a water temperature of 26.5 degrees Celsius for it to form. However once the cyclone is produced the water temperature will no matter as much only that more favourable water temperature means a longer lasting and persisting cyclones. They occur in areas of very low pressure when air that is heated by the sun rises rapidly, heating up water into thunderstorm clouds. They later clump together to make the bases for the cyclone.
The hot air then rises above leaving only the cold air underneath. Therefore this creates a low pressure system which is the next requirement for a cyclone. The Coriolis Effect of the Earth spins on its axis therefore creating a force which carries th...
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...ones/how-do-cyclones-form.html
• http://wiki.answers.com/Q/How_do_cyclones_form?#slide=1
• https://sites.google.com/site/disasterportal/stroms_cyclones/cyclone-formation
• http://www.gmat.unsw.edu.au/currentstudents/ug/projects/Darmawan/Cyclone.html
• http://www.abc.net.au/news/2011-02-01/tropical-cyclones-explained/1926870
• http://ntlapp.nt.gov.au/tracy/
• http://www.bom.gov.au/cyclone/history/tracy.shtml
• http://www.naa.gov.au/collection/fact-sheets/fs176.aspx
• http://www.em.gov.au/library/Onlineresources/Historicaldisasters/Pages/HistoricalDisastersCycloneTracy.aspx
• http://en.wikipedia.org/wiki/Cyclone_Tracy
• http://en.wikipedia.org/wiki/Threatened_fauna_of_Australia
• http://wiki.answers.com/Q/Did_the_SES_help_with_cyclone_Tracy
Books
• How to destroy the world and 34 other really interesting uses of physics- Paul Parson –
pg 14- 19, 26-31
Australia is a land of rather extreme weather conditions and widely diverse climates that force the vegetation living there to adapt in many interesting ways. Australia is the driest continent, and biomes such as grasslands and savannas are prime sources of widespread catastrophic fires. The plants that grow in the vast arid and semi-arid regions of Australia are prone to fires simply because of the desert climates that they grow in. High temperatures combined with low fuel moisture contents, little humidity and drying winds that sweep across the landscape encourage many of the plants living in these areas to burst into flames at fairly frequent intervals. Serotinous cones, protective bark, intricate underground recovery systems, unique seed distributions and even the necessity of fire for reproduction are just some of the amazing ways that the major plant families which grow in these fire-prone areas have learned to adapt to their environments.
2. The USA Today Tornado Information site also indicates that there are three key conditions for thunderstorms to form.
When passing through the northeastern United States tropical cyclones are restructured by the course of extratropical transition. This is caused by the contact with strong westerlies that are associated with a mid latitude trough and causes an enhance in storm forward motion, vertical wind shear, and vorticity. An increase in storm forward motion also plays a role in the wind speed that is produced by the hurricane. Where the circulating winds and the entire storm is moving in a matching direction, the wind speed is amplified by the forward movement of the storm. In the Northern Hemisphere, the right part of a hurricane, looking in the way of the path in which it is moving forward, has the greater wind speeds and thus is the more dangerous part of the storm. Strong vertical wind shear within the troposphere also reduces tropical cyclone development. This makes the e...
A bomb cyclone, or bombogenesis, is a winter storm much like a hurricane caused by jet stream and explosive cyclogenesis. An explosive cyclogenesis, also known as a weather bomb, is a process in which a storm falls 24 millibars in a 24 hour window causing extremely low pressure. Jet streams are what fuel a bomb cyclone. Jet streams are narrow bands of air higher up in atmosphere. Jet streams can switch between warm or cool air and in this case, it is cold air blowing over warm water. As the cold air blows over the warm water, the heat from the water rises and causes heavy precipitation. But, this is cold precipitation and snow can end up falling.
The birth of a hurricane requires at least three conditions. First, the ocean waters must be warm enough at the surface to put enough heat and moisture into the overlying atmosphere to provide the potential fuel for the thermodynamic engine that a hurricane becomes. Second, atmospheric moisture from seawater evaporation must combine with that heat and energy to form the powerful engine needed to propel a hurricane. Third, a wind pattern must be near the ocean surface to spirals air inward. At least 3 conditions must be present for a hurricane to emerge. Water, heat, and wind are the three main factors that have to be in perfect conditions to start a hurricane. (The Weather Channel, 2008)
A hurricane needs a couple of components to survive. One of them is warm water and the other is winds going the same direction. If a hurricane didn’t have either of those, it wouldn’t last very long or be destructive.
Climate change has the potential to devastate millions in Australia. Rising temperatures will impact the landscape of Australia by decreasing Australia's forests. Australia is going to have to spend billions of dollars to make sure their safety from climate change. The people in Australia will need to be strong and flexible to make it through this tough time they're going through, and Australia will have to find a way to fix this problem before it's too late. Climate change is something that will affect the entire world and it's not an issue to take lightly. Australia’s solutions are not simple at all and in order for them to work everyone will have to work together. Climate change in Australia will impact the environment, the economy, and the lives of Australians, an example of a solution is to cut down on carbon emissions.
Hurricanes form over the ocean. Easterly waves, what hurricanes develop from, are long, narrow regions of low pressure which occur in ocean winds called trade winds. At first, these easterly waves can grow into something called, a tropical depression. A tropical depression occurs when winds are up to 31 mph. Then tropical depressions can be upgraded into a tropical storm if the winds reach speeds of 74 mph or less. Then finally a the storm can be bumped up into a hurricane if the winds reach 75 mph.
Hurricanes begin as tropical disturbances in warm ocean waters with temperatures of at least 80 degrees Fahrenheit. These low pressure systems are served by energy from the warm seas. If a storm reaches wind speeds of 38 miles an hour, it is known as a tropical depression. A tropical depression becomes a tropical storm, and is given a name, when its sustained wind speeds top 39 miles an hour. When a storm’s sustained wind speeds reach 74 miles an hour, it becomes a hurricane and earns a category rating of 1 to 5 on the Saffir-Simpson scale.
Natural Disasters can occur anywhere at anytime. Some are more predictable than others, but they all bring hardship to everyone’s life. Examples of natural disasters are Earthquakes (Haiti 2010), Tornadoes, Tsunami, Hurricanes, Wild Fires, Winter Storms, Heat waves, Mudslides and Floods. Regardless of what kind of disaster occurs, bottom line, everyone needs to be prepared mentally and physically to deal with the aftermath. Education is the first step to prepare you to deal with any major disaster. Three of the major disasters that can potentially disrupt normal day to day operations in our lives, are Hurricanes, Tsunamis and Tornadoes.
For a hurricane to form, the ocean temperature must be warmer than twenty-six degrees Celsius, or eighty degrees Fahrenheit. Also, the air near the oceans surface must be filled with moisture. The seawater that is warmed by the heat from the sun evaporates to form vast storm clouds. As the warm air rises, the cooler air replaces it thus creating a wind. The rotation of the earth bends the wind inward causing it to rotate and spiral upward with a great amount of force. Around the Equator, the spin is the fastest. There, it can be faster than six hundred miles per hour.
There are different types and causes of disasters: man-made, natural and a combination. Man-made disasters are caused by human error or human actions that cause harm to the environment, and people (Baack & Alfred, 2013). Natural disasters are caused by nature, a hurricane for example, and a combination of NA-TECH (natural-technological). Examples are earthquakes that cause structural damage such as a collapse of a bridge (Nies & McEwen, 2011). Communities must have effective emergency preparedness in place to reduce the casualties of a disaster.
A tropical cyclone is a warm-core, low-pressure system producing high winds that spiral counter-clockwise (in the northern hemisphere) and inward, with the highest winds near the center of circulation. The large counter-clockwise and inward flow is characteristic of the nearly symmetric structure of tropical cyclones as they are comprised of rain bands spiraling toward the center. These warm-core storms typically form over the tropical and subtropical oceans and extract their energy from the heat content of the oceans.
The least violent type of natural disasters is the flood; it is one of the most frequent hazards. A flood can affect local areas or a very large area affecting entire river deltas. Not all foods are alike, some of them develop slowly over a period days and some of them occur in a matter of minutes. The floods that develop quickly are known as flash floods; flash floods have a dangerous wall of thunderous water that carries rocks, mud and other different debris. If you live in a low-lying area near water you more prone to flooding, the smallest streams, gullies, creeks, and streambeds can cause a flood. Floods are often not a common thought when you think of a natural disaster, but they can be fatal, destroy homes, businesses, and roads, happen when you least expect, and happen when you are not prepared (FEMA:Flood). An extreme example of this type of natural disaster is the flood in eastern Australia last month; the flood, which lasted for weeks, caused thirty dea...