Processes Causing Formation + Dev of Cyclones + Tornadoes

Question 1

What is a cyclone?

Answer 1

• a low pressure, spinning storm w high winds + severe rain

Question 2

What are the certain conditions required for cyclones to form + develop?

Answer 2

• warm ocean T°Cs, around 26-27°C, that are at least 60m deep to provide storm w energy
• unstable air pressure, usually formed when high pressure meets low pressure, so warm air can rise more readily, bc is less dense, + clouds can form
• pre-existing winds to allow swirling motions to form
• coriolis effect (effect of Earth’s rotation) is required to generate rotation needed, so cyclones only form >5° N or S of equator
• a trigger, in the form of a pre-existing thunderstorm, an area of high sea surface T°C, or an area of low pressure

Question 3

Describe the formation of cyclones.

Answer 3

• warm, moist air rises, leaving an area of low pressure below
• this causes warm air, from surrounding areas of higher pressure, to move into this low pressure area + rise too, + so warm air rises + accumulates in atmo.
• when warm air rises, it cools + condenses into thunderstorm clouds
• this whole system spins due to Coriolis effect
• as more warm air moves into this low pressure area, it provides more energy for storm to spin faster + generate higher wind speeds, in which pressure differences cause more air to be sucked towards centre, inc wind speeds
• when wind speeds reach 74mph, a cyclone is formed

Question 4

What is a tornado?

Answer 4

• a violently rotating moving vortex of air

Question 5

Describe the formation of tornadoes.

Answer 5

• sun heats ground, causing hot air to rise + condense into clouds
• if higher winds are stronger + faster than winds lower down, they start to roll underneath weaker winds, creating a rolling horizontal cylinder of wind
• as powerful, hot updraughts of air continue to rise, horizontal cylinder is forced upwards into a rotating vertical column of air to form a supercell
• cool, dry downdraughts of air pull rotating air downwards, causing spinning vortex to spin faster + become tighter
• when it reaches ground, a tornado is formed