2.4 Climate and biomes

Objective notes

13 learning objectives

2.4.1Climate vs. weather

• Climate: atmospheric conditions over long periods (~30 years)

• Weather: short-term conditions

2.4.2Biome definition

• Group of comparable ecosystems in similar climatic conditions

• Influenced by precipitation, temperature, insolation

2.4.3Biome distribution determinants

• Abiotic factors

• Temperature and rainfall patterns determine ecosystem type

2.4.4Biome categories

• Freshwater, marine, forest, grassland, desert, tundra

• Each has characteristic limiting factors, productivity, diversity

2.4.5Tricellular model

• Explains atmospheric circulation

• Distribution of precipitation and temperature by latitude

• Three cells: Hadley, Ferrel, polar

2.4.6Ocean heat distribution

• Oceans absorb solar radiation

• Ocean currents distribute heat globally

2.4.7Global warming effects

• Changing climates and biome shifts

• General trend: poleward and higher altitude movement

2.4.8(HL)—Climate type patterns

• Tropical (seasonal and equatorial)

• Temperate (maritime and continental)

• Polar

2.4.9(HL)—Secondary influences

• Temperature/rainfall pattern may not determine biome

• Human interventions, local conditions affect development

2.4.10(HL)—ENSO cycle

• El Niño Southern Oscillation

• Fluctuation in wind and sea surface temperatures (tropical Pacific)

• El Niño and La Niña: opposite extreme states

2.4.11(HL)—ENSO mechanisms

• El Niño: weakened Walker circulation, decreased upwelling

• La Niña: strengthened Walker circulation

2.4.12(HL)—Tropical cyclones

• Low-pressure systems with strong winds

• Hurricanes/typhoons: sustained winds > 119 km/hr

2.4.13(HL)—Global warming and cyclones

• Rising ocean temperatures increase intensity and frequency

• Warmer water and air have more energy