Tropical Storms Flashcards
(27 cards)
Where do tropical storms form?
In low pressure bands such as the ITCZ.
5°-30°N or S of the equator.
What temperature must ocean water be for tropical storms to form?
At least 27°c.
What conditions do tropical storms need in order to form?
Warm, open, deep water.
Low pressure.
Low latitude winds blowing toward eachother.
What depth must the ocean be for tropical storms to form?
At least 70 metres deep.
Why does the ocean have to be at least 27°c for a tropical storm to form?
Ocean water needs to be warm enough to evaporate into water vapour.
How large can tropical storms grow in diameter?
Up to 2,000km however majority are around 200-500km.
How do tropical storms become self-sustaining?
Warm air/ water vapour rises, cools, and is pushed outwards where it falls back into a stream of hot air toward the eye of the storm.
What is the coriolis effect’s influence on tropical storms?
The coriolis effect causes oncoming winds to be deflected which contributes to the spinning motion of the storm.
What are the six steps to the formation of a tropical storm?
- A strong upward movement of air draws water vapour up from the warm (27°c) ocean surface.
- The air evaporates as it rises, creating a dense thunderstorm cloud. When it condenses, it releases latent heat which powers the storm to draw up more water.
- Smaller storms join to form a giant spinning storm. When surface winds reach 75mph, it is oficially a tropical storm. A self-sustaining energy flow is created by rising and falling winds.
- The coriolis force enhances the spin of the storm. The eye of the storm develops where air descends rapidly.
- The storm is carried across the ocean by prevailing winds where it continues to gain strength.
- On reaching land, the storm’s energy supply is cut off and friction with the land slows it down which weakens the storm. The storm can pick up strength if reaching water again.
Which part of the tropical storm experiences the most intense weather conditions?
The eyewall.
What surface wind speed determines the classification of a tropical storm?
125km/h (75mph).
What are the three cells which make up global atmospheric circulation?
The Polar Cell.
The Ferrel Cell.
The Hadley Cell.
Which 3 latitudes experience low pressure rising air?
60°N.
0°.
60°S.
Which 4 Latitudes experience high pressure descending air?
90°N.
30°N.
30°S.
90°N.
Why do deserts form at 90° and 30° N and S?
When air sinks, it creates a high pressure area which doesnt allow clouds to form, creating the arid climate of deserts.
Why does tropical and temperate biomes form at 0° and 60° N and S?
Sinking air allows for water vapour to form clouds, which precipitate, creating tropical and temperate biomes.
Why do Tropical Storms form 5°-30°N and S of the equator?
Coriolis effect is strongest here.
Avg sea temperatures are highest here.
Averagely, how large is the storm eye in diameter?
10-15km.
What scale are tropical storms measured against?
The Saffir-Simpson Scale.
What are the critical evaluations of the Saffir-Simpson scale?
It only predicts / measures damage from wind.
In recent years, what percentage of deaths caused by tropical storms in the USA were caused by storm surges and inland flooding?
90%.
What is the average lifespan of tropical storms?
7-14 days.
How does climate change affect the magnitude of tropical storms?
They may last longer and they may be more severe.
Does climate change have an affect on the frequency of tropical storms?
There is no evidence to prove this.
