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AS Edexcel Geography - Can anyone explain the Coriolis effect to me? :(

I am completely stuck on how tropical cyclones form. My book says, 'they don't form over 5 latitude, because the Coriolis effect isn't strong enough...'

Please could anyone explain to me what do they mean by '5 latitude' and what exactly is the Coriolis effect?

I am doing AS Geography Unit 2, Extreme Weather.

Reply 1

Cetacea

Tropical storms are intense low pressure weather systems that develop in the tropics, in 5 degrees of latitude either North or South from the equator (this is what you were wondering). They can't form in the first 5 degrees of latitude closest to the equator because the Coriolis effect, which is caused by the Earth's rotation, is not optimum at the equator. The Coriolis effect causes the air in tropical storms to rotate around a low pressure centre.

There are two other requirements that need to be met before tropical storms can form:
-Sea surface temperatures of over 27C to provide a sufficient heat source
-An ocean depth of at least 70m - this quantity of moisture is sufficient to drive the system.

Tropical storms begin with an area of low pressure caused by surface heating, into which warm air is drawn in a spiraling manner. This enlarges into a tropical depression with rotating wind systems, usually 200-700km in diameter.

Hope that helps!

Reply 2

Aysha_B

The Coriolis effect happens as the earth rotates. So in the northern hemisphere, the air moves from high to low pressure and deflects air to the right, and vice versa in the southern hemisphere. Tropical cyclones in the northern hemisphere usually turn north, and in the Southern Hemisphere usually turn south.

Tropical cyclones don't occur at 5 degrees latitude of the equator as the Coriolis force doesn't exist at the equator; the force is low there.

Good luck with your geography revision! :smile: