Global Wind Patterns
Introduced| English |
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| Coriolis effect/ˌkɒrɪˈəʊliz ɪˈfekt/ |
Why the wind blows
- Winds are not random — they follow steady global patterns.
- The same belts of wind have blown for millions of years.
- They decide where rainforests grow and where deserts spread.
- It all starts with the Sun heating the Earth unevenly.
Uneven heating
- The Sun heats the equator far more than the poles.
- Warm air is less dense, so it rises high into the sky.
- As it rises it cools and drops heavy rain.
- This is why lush rainforests ring the equator.
What ultimately drives global wind patterns?
The Sun heats the equator more than the poles; this uneven heating drives the winds.
Rising and sinking air
- The dry air, now high up, spreads away from the equator.
- Around 30 degrees latitude it cools and sinks back down.
- Sinking dry air brings little rain, creating deserts like the Sahara.
- This rising and sinking sets up huge circulation cells.
Why winds blow
Step through the cycle - the Sun heats the equator, air rises, and circulation cells drive the global winds.
Warm air at the equator tends to…
Warm, less-dense air rises, cools, and releases rain — that is why rainforests ring the equator.
Dry air sinking around 30 degrees latitude creates many of the world's ____.
The sinking dry air near 30 degrees gives little rain, forming deserts like the Sahara.
The winds curve
- Air flowing along the surface would blow in straight lines — but Earth is spinning.
- Earth's rotation bends the moving air (the Coriolis effect 科里奥利效应).
- This curving creates steady belts like the trade winds.
- Sailors have relied on these predictable winds for centuries.
Earth's rotation bends the moving air, giving winds their curved paths.
The Coriolis effect from Earth's spin curves the winds, creating patterns like the trade winds.
Select all true statements about global wind patterns.
The Sun is the ultimate driver of the winds. The other three are correct.
The whole pattern traces back to the Sun, not to random chance. Uneven heating makes air rise at the equator and sink near 30 degrees — which is why the world's great deserts and rainforests sit in predictable latitude bands, not just anywhere.
Rainforest and desert, side by side in latitude:
- At the equator, rising air dumps rain — home to the Amazon and Congo rainforests.
- Near 30 degrees north and south, sinking dry air starves the land of rain — home to the Sahara and Australian deserts.
- The same circulation makes both, just at different latitudes.
Global wind patterns are driven by the Sun's uneven heating of Earth. Warm air rises at the equator (heavy rain, rainforests) and sinks near 30 degrees (dry air, deserts). Earth's rotation bends the moving air through the Coriolis effect, creating steady wind belts like the trade winds.