Tropical storms - Paper 1 Flashcards
Describe the sequence of formation of a tropical storm:
1) Air above the surface of warm oceans is heated and rises rapidly under low-pressure conditions.
2) As this air rises, it draws up more air and large volumes of moisture from the ocean. This creates strong winds.
3) The coriolis effect causes the air to spin upwards around a calm, central ‘eye’ of the storm.
4) As air rises, it cools and condenses forming large cumulonimbus clouds. This generates torrential rainfall. The heat given off when air cools is what powers the storm (latent heat).
5) Cold air sinks in the eye of the storm, therefor there is no cloud and it is much calmer and drier here.
6) The storm travels across the ocean in the prevailing wind.
7) When the tropical storm meets land, it is no longer fuelled by its source of heat and moisture from the ocean so loses power and weakens.
What ocean conditions are needed for tropical storms to form?
Above 27 degrees celcius.
Ocean depth of 60-70 metres.
Do tropical storms form on the equator? Explain.
They do not form on the equator as the coriolis effect is not strong enough here for tropical storms to spin.
What is the relationship between the formation of tropical storms and the global atmospheric circulation model.
Areas of low latitude (5-30 degrees N + S of the equator) and high insolation. Also require a low wind shear to stop tropical storm clouds being torn apart at high levels. Dont form on equator as coriolis effect is not strong enough here for tropical storms to spin.
How does climate change affect the intensity of tropical storms?
-Storms are expected to become more intense, by 2-11% by 2100.
-Will increase the number of more severe tropical storms (category 4 and 5) but decrease the number of calmer ones (category 1-3)
-Predictions suggest that for every 1 degree celcius increase in ocean temperature, wind speed will increase by 3-5%.
How does climate change affect the frequency of tropical storms?
-The overall frequency is expected to either remain the same or decrease due to climate change.
-Will increase the number of more severe tropical storms (category 4 and 5) but decrease the number of calmer ones (category 1-3)
How does climate change affect the distribution of tropical storms?
-The regions where tropical storms are experienced are not expected to change significantly as a result of climate change
-They might spread to higher latitudes and other areas as more oceans warm to 27C or above
How do satellites monitor tropical storms? Explain.
There is a classic cloud pattern of tropical storms which satellites can monitor. In 1997, it was accidentally discovered that rainclouds which reach approximately 16km in altitude are more likely to indicate that a tropical storm will intensify in 24 hours. 7 years later, the Global Precipitation Measurement satellite was launched. It monitors precipitation every 3 hours between latitudes 65 degrees N + S of the Equator to identify high altitude rain clouds.
How can monitoring reduce the effect of tropical storms? What are 2 ways.
Monitoring tropical storms allows predictions to be made which can save lives and reduce damage.
-Satellites
-Aircraft
How do aircrafts monitor tropical storms? Explain.
Specially equipped aircrafts frequently fly through tropical storms at 10,000 ft high to collect air pressure, precipitation and wind speed data. They release dropsondes (sensors) which send measurements every second by radio.
How can planning reduce the effect of tropical storms?
American National Hurricane Preparedness week in May advises:
-Preparing disaster supply kits
-Having fuel in vehicles
-Storing loose objects
-Knowing where official evacuation shelters are
-Planning with family what to do.
How can prediction reduce the effect of tropical storms? Name 3 examples.
-Supercomputers
-Track cones
-National hurricane centres around the world issue early warning so people have time to prepare to evacuate - but some may not bother.
Give an example of how supercomputers predict tropical storms?
In 2013, the National Oceanic and Atmospheric Administration developed 2 new supercomputers, which could give 5 days warning of a tropical storm and a more accurate location within 400km.
How do ‘track cones’ predict tropical storms?
The national Hurricane Centre in Florida predicts a tropical storm’s path and intensity for up to 7 days using a ‘track cone’.The cone shape allows for error with the unpredictable behaviour of the tropical storm, especially when it hits land. Around 70% of tropical storms occur within the predicted cone.
How can protection reduce the effect of tropical storms?
The Federal Emergency Administration Agency advises home owners to:
-Install hurricane straps (galvanised metal) between the roof and walls
-Install storm shutters on windows
-Install an emergency generator
-Tie down windbourne objects such as garden furniture
-Reinforce garage doors
-Remove trees close to buildings.
