What are tropical storms?
Tropical storms are huge storms that are incredibly powerful and can cause devastation to small islands and coastal regions. Intense areas of low pressure
In the USA and Caribbean what do they call tropical storms?
Hurricanes
In south east Asia and Australia, what do they call tropical storms?
Cyclones
What do they call tropical storms in the Philippines and Japan?
Typhoons
Describe the distribution of tropical storms?
- Occur within the tropics of cancer and the Tropic of Capricorn 5 degrees and 20 degrees north and south of the equator
- equator runs through the Pacific Ocean, Atlantic Ocean and the Indian Ocean
- north of the equator, move Westwood and also south
- occur most on the western side of Central America and off south east Asia
What are the nature of tropical storms?
- intense low pressure weather systems
- develop in the tropics
- usually measure 200-700km in diameter
- they begin with an area of low pressure resulting from surface heating into which warm air is drawn in a spiralling manner
- small scale disturbances can enlarge into tropical depressions with rotating wind systems and these may continue to grow into a much more intense and rapidly rotating system the TRS
Oceans need to be a temperature of 27 degrees Celsius, why is this?
This provides a continuous source of heat in order to maintain rising air currents
Oceans need to be a depth of at least 70m, why is this?
The moisture provides latent heat: rising air causes the moisture to be released by condensation and continuation of this drives the system
Why must it be 5 degrees north or south of the equator?
In order that the Coriolis force can bring about the maximum rotation of the air
There must be a low level of convergence air why is this?
In the lower atmospheric circulation system winds have come together near the centre of the low pressure zone
Atmospheric instability is a important condition, why?
Rapid outflow of air in the atmospheric circulation- this pushes away the warm air which has risen close to the centre of the storm
Latent heat and a moisture supply is important, why?
This provides energy and low frictional drag on the ocean surface
Once a storm develops, what happens?
- central eye develops, this area 10-15km in diameter in which there are calm conditions, clear skies, higher temperatures and descending air
- wind speeds of more than 300km/hr have been observed around the eye
- once the system reaches land or colder waters pole wards, it will decline as the source of heat and moisture is removed
What are the characteristics of a tropical storm?
- symmetry around the eye
- the most damaging is the bank of cloud the rings the central eye, called the eye wall
- cloud and rain extended in a series of waves beyond the eye wall
- tornadoes can be formed within a TRS
- life span of 7-14 days
- 80-100 storms a year 80% become TRS
What do we use to measure the magnitude of a tropical storm?
The Saffir Simpson Scale
When was the scale developed?
1917
What is the scale based on?
Central pressure, wind speed storm and potential damage
What does the scale by take into account?
Rainfall therefore it has a limitation
What does the overall pattern show as the category increases?
As the category increases, the wind and storm surge increase but however the surface pressure decreases as the category increases
Are the higher category’s always the most destructive?
Depending on the location, population density, wether or not the country is a LIC or HIC and how infrastructure is built
What is the first step in explaining a tropical storm?
The sun sends incoming solar radiation to earth which warms our oceans
What is the second step in explaining a tropical storm?
This warms the oceans to a critical 27 degrees Celsius
What is the third step in explaining a tropical storm?
The high sea temperature causes the warm moist air to rise from the ocean through the air in thermals
What is the forth step in explaining a tropical storm?
The evaporated air cools as it rises and condenses to form towering thunderstorm clouds
