Climates and biomes
A place's climate comes from three things: latitude, altitude and what the sea next door is doing. Latitude shares out the Sun's energy, and that produces the bands: rainforest at the equator, desert around 30°, temperate around 45°, polar at the top. The deserts at 30° are no accident: air rises hot and wet at the equator, drops its rain, crosses at altitude and comes down dry right there; it is called the Hadley cell. Altitude removes about 6.5 °C per thousand metres, which is why there is snow at the equator. And ocean currents upset the sums: the North Atlantic Drift keeps Norway ice-free at Greenland's latitude. Köppen sorted all this into five letters: A tropical, B dry, C temperate, D continental, E polar.
Where this sits
- Comes after
- Mountains and plains
Exercises from this rung
Generated by the app, from easiest to hardest
The Köppen classification sorts climates into five groups. Which?
- Tropical, dry, temperate, continental and polar
- Rainforest, savanna, desert, forest and tundra
- Hot, cold, wet, dry and mountainous
- North, south, east, west and central
Why Köppen named them with letters: A tropical, B dry, C temperate, D continental and E polar, then added a second and third letter for rainfall regime and summer. Csa, for instance, is the Mediterranean climate: temperate, with a dry hot summer. He based it on vegetation, on the idea that plants have already done the measuring over centuries.
easierWhat sets the Mediterranean climate apart?
- Summer is the dry season
- It has no seasons
- It never freezes
- Rain falls evenly all year
Why Almost everywhere summer brings the rain, because heat pushes air upwards. In the Mediterranean climate the reverse happens: in summer the subtropical high from 30° moves in and dries the sky, and the rain retreats to autumn and winter. It occurs in five places on Earth, all on west coasts around 35°: the Mediterranean basin, California, central Chile, the Cape and southwest Australia.
in betweenIndia sits in the desert band by latitude and yet is one of the rainiest regions on Earth. Why?
- The monsoon
- Because latitude is calculated differently in Asia
- Because the Himalaya attracts clouds
- Because it is surrounded by sea on three sides
Why In summer the interior of Asia heats far faster than the Indian Ocean, and the rising warm air leaves a gap filled by humid air from the sea: that is the monsoon, and it dumps some 11,000 mm a year on Cherrapunji. Latitude climate bands are the first approximation, not the last word: currents, altitude and the shape of the continents break them constantly.
harder