Factors Affecting Climate Ch 3.2

Low Latitudes Between the “Tropics” Receive direct rays from Sun Low numbers in latitude value Receive direct rays from Sun Equator: 6 mos. a yr. Each Tropic: 3 mos. a yr. Receive indirect rays from Sun Each Tropic: 6 mos. a yr. Warm to hot climates year round

High Latitudes Polar areas= N of Arctic Circle and S of Antarctic Circle (high numbers in latitude value) Receives constant sunlight for 6 months when pole faces Sun March-Sept: North has constant daylight, South is in dark (switches for next 6 mos.) Arctic & Antarctic Circles are last point to receive indirect rays (during their summer)

Mid Latitudes Most variable weather on Earth Between Trop. of Cancer & Arctic Circle; between Trop. of Capricorn & Antarctic Circle (~30°- 60°) Ranges from fairly hot to fairly cold (temperate), dramatic changes (seasons), but no extremes Summer gets warm air from low-lats, winter gets cold air from high-lats

Elevation

Elevation At any latitude, anywhere on Earth, elevation influences climate If high enough in elevation, can have snow on the Equator! As altitude increases, the air thins which absorbs less heat As elevation increases, temperature decreases (3.5° per 1,000 ft)

*(named for direction they come FROM) Wind Patterns Move clockwise in N. Hem. and counterclockwise in S. Hem. (Coriolis Effect) Cool air flows in to replace rising warm air (Polar front), distributing Sun’s heat Switches direction in each latitude zone Low latitudes have trade winds (northeasterly/southeasterly) Mid-latitudes have westerlies High latitudes have polar easterlies *(named for direction they come FROM) Windless bands Doldrums @ Equator Horse Latitudes @ Tropics

Ocean Currents Flow same directions as wind…which is?? Cold water moves from poles to Equator and warms up (cold currents), or warm water moves from Equator to poles and cools (warm currents) Currents affect the climate on land: either cooling or warming (ex: North Atlantic Drift & W. Europe)

El Niño Periodic change in currents & water temps. in mid-Pacific region No known cause Reversal of atmospheric pressures  reduce or reverse wind patterns brings warm water from Asia to South America Domino effect: Precipitation increases, flooding in S. America Or droughts and fires in SE Asia/Australia

El Niño

Landforms Bodies of water moderate temps. b/c they take a long time to change temp. Gulf of MX is warm water keeps Houston warmer Continentality– absence of lg. body of water means more drastic weather changes Nebraska can have hot summers and receive snow in the winters (4 seasons instead of 2  ) Rainshadow Effect Cool air releases moisture on windward side of mountain; then hot, dry air moves to leeward side creating deserts

Ganges Plain in India Himalaya Arid Tibetan Plateau