Atmospheric Circulation Lab
The global atmospheric circulation model: the cells and pressure belts that make the air rise at the equator and sink near thirty degrees, and how that sets the pattern of rainforests, deserts and where tropical storms form.
Use it, the way the marks are given
Free interactive practice at using the material, which is what the marks are for.
Start revising freeWhat you'll cover
Why deserts and rainforests?
Why is there thick rainforest at the equator but hot desert a little further north and south? The answer is the way air moves around the planet. Warm air rises in some places and sinks in others, and that sets where it rains and where it stays dry. This module builds the global atmospheric circulation model and links it to real climates.
Circulation vocabulary
Learn these four terms before you study the model.
Rising or sinking
Two belts of pressure decide where it rains.
Link the model to places
A top answer never describes the loops on their own. It links them to real places: rising air and low pressure at the equator make the rainforests, while sinking air and high pressure near thirty degrees make the deserts. It also explains that warm ocean and low pressure near the equator are exactly where tropical storms begin.
Match the term
- atmospheric circulation
- the Hadley cell
- low pressure
- high pressure
- air moving in giant loops around the planet
- the loop between the equator and thirty degrees
- rising air that brings clouds and rain
- sinking air that brings dry, clear skies
Match the place
- the equator
- around thirty degrees
- rising air
- sinking air
- where rainforests grow
- where deserts form
- brings rain and low pressure
- brings dry weather and high pressure
Air at the equator
What happens to the air at the equator, and what does it cause?
- It rises, giving low pressure and rain.
- It sinks, giving high pressure and desert.
- It stays still, giving no weather.
- It freezes, giving snow.
High pressure belts
Select the TWO things that happen in a high pressure belt near thirty degrees.
- Air sinks towards the surface.
- Dry deserts tend to form.
- Heavy daily rain falls.
- Air rises quickly.
Order the Hadley cell
Put the stages of the Hadley cell in order, earliest first.
- The sun heats the equator
- Warm air rises, giving low pressure
- Clouds and rain form the rainforests
- The air moves out to about thirty degrees
- The air sinks, giving high pressure and desert
Complete the facts
The movement of air in giant loops is atmospheric _____. At the equator warm air _____, giving low pressure and rain. Near thirty degrees the air _____, giving high pressure. Rising air feeds the _____ at the equator, while sinking air forms the _____ near thirty degrees.
Count the cells
In each half of the planet there are 3 circulation cells: Hadley, Ferrel and Polar. Counting both the northern and southern halves, multiply 3 by 2 to find the total number of cells. What is the answer?
Describe the equator
Tap the TWO statements that describe the equator.
- warm air rises here
- heavy rain feeds rainforests
- air sinks to the surface here
- dry deserts form here
Read the latitude
Read each place and choose what its air and climate are like.
- A place lies right on the equator over warm land. What is its air and climate like?
- A place lies near thirty degrees where the Hadley cell air returns to the surface. What is it like?
- A tropical storm is forming. Which conditions near the equator does it need?
Explain the circulation
Explain the global atmospheric circulation and why rainforests and deserts are found where they are.
- Describe what happens to the air at the equator
- Describe what happens to the air near thirty degrees
- Explain how this creates rainforests and deserts in their places