2.4 Climate and biomes

Weather

The atmospheric conditions at a particular place and time, changing over minutes to days

Climate

The average of weather conditions over a long period in a region, showing long‑term patterns of temperature, precipitation and other variables

Biome

A group of ecosystems that have developed under similar climatic conditions, characterised by similar dominant vegetation, climate and abiotic factors

Abiotic factors

Non‑living physical and chemical components of the environment that influence biome distribution and productivity

Tropical rainforest

Warm region with high rainfall, complex vertical vegetation structure, exceptionally high biodiversity and productivit

Desert biome

Very low precipitation, sparse vegetation, extreme temperature fluctuations, low productivity.

Tundra biome

Cold climate, permafrost soils, short growing seasons, low shrubs/herbs, low biomass productivity.

Savanna biome

Seasonal climate, grasses with scattered trees, fire and grazing important, moderate productivity.

Temperate forest biome

Seasonal climate with moderate rainfall, broad‑leaf or mixed forests, relatively high biodiversity and productivity

Hadley cell

A tropical atmospheric circulation cell where warm air rises near the equator, moves poleward at high altitude, cools and sinks at 30 degree latitude, creating deserts and trade winds.

Ferrel cell

A mid-latitude circulation cell between 30 degree and 60 degree latitude where air moves opposite to Hadley and Polar cells, surface air moves poleward, rises near 60 degrees, sinks near 30 degrees, driving westerly winds.

Polar cell

A circulation cell at high latitudes 60 - 90 degrees where cold air sinks at the poles, moves equatorward at the surface, warms and rises near 60 degrees, producing polar easterlies and low temperatures.