Tropical cyclones are powerful rotating storms that form over warm tropical or subtropical waters. Understanding their structure and formation helps explain why they can become dangerous and why they do not form everywhere.
A tropical cyclone is a warm-cored, non-frontal low-pressure system over tropical or subtropical waters. It has a closed surface circulation and deep thunderstorms around a well-defined center. Once mean surface winds exceed about 35 knots (65 km/h), the system is generally considered self-sustaining and formed.
All flashcards
What is a tropical cyclone?
A warm-cored, rotating low-pressure system over tropical or subtropical waters, with a closed surface circulation and organized thunderstorms.
What fuels a tropical cyclone?
Evaporation from warm ocean water supplies moist air. When that air rises, cools, and condenses, heat is released and helps power the storm.
What does vertical wind shear mean?
It is a change in wind speed or direction with height. Strong shear can disrupt a cyclone’s circulation and thunderstorms; low shear favors organization.
How does the Coriolis effect shape cyclone rotation?
It helps organize the storm’s rotating circulation: counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
Why is the ITCZ relevant to formation?
The ITCZ is a broad low-pressure zone where winds converge. Rising warm, moist air there can form thunderstorm clusters that may develop into a cyclone.
Quiz questions
What determines whether a strong tropical cyclone is called a hurricane or a typhoon?Answer: The ocean basin where the storm occurs.
Where are the strongest winds and heaviest rain typically found in a mature tropical cyclone?Answer: In the eyewall surrounding the eye.
What wind-speed change defines rapid intensification in a tropical cyclone?Answer: An increase of at least 30 knots in maximum sustained winds within 24 hours.
What mainly controls the track of a tropical cyclone?Answer: Large-scale atmospheric winds surrounding the storm.
What causes storm surge during a tropical cyclone?Answer: A storm-driven rise in coastal water level.
Based on the Wikipedia article Tropical cyclone, licensed CC BY-SA 4.0. Adapted into a summary, flashcards and quizzes.