Between which latitudes do tropical storms form, and why not over the equator itself?

Roughly 5° to 30° north and south, because the spin given by the Earth’s rotation is too weak at the equator to set a storm turning.

Explain how a tropical storm builds once the ocean is warm enough.

Warm moist air rises rapidly and condenses, releasing latent heat that drives the air upwards harder still and sucks in more air at the surface, strengthening the winds.

Why does a tropical storm weaken once it crosses the coast?

It is cut off from the warm ocean water that supplied its heat and moisture, and friction with the land slows its winds.

What weather conditions cause a drought?

A long spell of rainfall well below average, often because high pressure settles over a region for weeks and blocks the rain-bearing systems.

OCR GCSE Geography A J383

Ecosystems of the Planet

Topic overview Abiotic and biotic components, and how ecosystems interact The world’s biomes: where they are and what they are like Where the tropical rainforests are, and what they are like Where the coral reefs are, and what they are like Rainforest processes and nutrient cycling Two threatened ecosystems: a rainforest and a coral reef

Environmental Threats to Our Planet

Topic overview Climate change through the Quaternary, and since 1000AD The evidence for climate change Natural causes of climate change, and the enhanced greenhouse effect The consequences of climate change The world’s climatic regions and global atmospheric circulation How global circulation produces extreme weather Tropical storms: causes, distribution and frequency A drought caused by El Niño or La Niña

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Landscapes of the UK

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People of the Planet

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People of the UK

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UK Environmental Challenges

Topic overview Air masses, the North Atlantic Drift and the UK’s extreme weather A UK flood event: causes, effects and responses How people use, modify and change UK ecosystems The UK’s renewable and non-renewable energy sources Changing UK energy supply and demand, and sustainable use Renewables in the UK, and the future of fossil fuels What shapes the UK’s energy choices

Environmental Threats to Our Planet

Tropical storms: causes, distribution and frequency

3 things to know
Component 02

Overview

The sea conditions and latitudes tropical storms need, how a storm builds and why it weakens over land, the eye, where storms are concentrated, and the causes, distribution and changing pattern of drought.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

What sea conditions must be present before a tropical storm can develop?

Key term

What is the eye of a tropical storm?

Key term

Has the number of tropical storms forming each year clearly risen?

Questions from this subtopic

Each one with the model answer underneath.

1
What sea conditions must be present before a tropical storm can develop?
Model answer
Ocean water at 27°C or above, warm to a depth of roughly 60 metres, supplying heat and moisture to the air above.
2
Between which latitudes do tropical storms form, and why not over the equator itself?
Model answer
Roughly 5° to 30° north and south, because the spin given by the Earth’s rotation is too weak at the equator to set a storm turning.
3
Explain how a tropical storm builds once the ocean is warm enough.
Model answer
Warm moist air rises rapidly and condenses, releasing latent heat that drives the air upwards harder still and sucks in more air at the surface, strengthening the winds.
4
Why does a tropical storm weaken once it crosses the coast?
Model answer
It is cut off from the warm ocean water that supplied its heat and moisture, and friction with the land slows its winds.
5
What is the eye of a tropical storm?
Model answer
The calm core of gently sinking air, with light winds and clear sky, ringed by the eyewall where winds and rainfall are at their most violent.
6
What weather conditions cause a drought?
Model answer
A long spell of rainfall well below average, often because high pressure settles over a region for weeks and blocks the rain-bearing systems.

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Ecosystems of the Planet

Environmental Threats to Our Planet

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The trade winds drive warm surface water .

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AMore sunspots mean the Sun is giving out more energy.

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