Factors Affecting Climate

An easy way to remember…

O-oceans & currentsW-wind patternsE-elevationL-latitudeL-landforms

LATITUDE

LOW LATITUDESMID LATITUDESHIGH LATITUDES

Low Latitudes

Located between the Tropic of Cancer and Tropic of Capricorn(23 ½ degrees north to 23 ½ degrees south)

Direct sunlight year-round

Very warm/hot climates

Middle Latitudes

Northern Hemisphere: Tropic of Cancer to Arctic Circle

Southern Hemisphere: Tropic of Capricorn to Antarctic Circle (23 ½ degrees N to 66 ½ degrees N)

(23 ½ degrees S to 66 ½ degrees S)

Middle Latitudes

Summer: Warm airWinter: Cold airTemperate climate-ranges from fairly hot to fairly cold.

Weather changes dramatically with seasons

High LatitudesNorthern Hemisphere: North Pole to Arctic Circle

Southern Hemisphere: South Pole to Antarctic Circle 66 ½ degrees N to 90 degrees N66 ½ degrees S to 90 degrees S

Indirect sunlight; cold climate

ELEVATIONAir temps decrease with elevati

onFor every 1,000 ft increase in elevation, the temp drops by 3 ½ degrees.

Example: Quito, EcuadorElevation of 9,000 ft.25 degrees cooler than surrounding areas

Wind

Wind is caused by differences in air pressure from one place to another. High pressure always flows into low pressure. Wind direction always refers to direction wind

is blowing FROM. Example: westerlies : wind is coming from the west towards the east.

Why doesn’t wind blow straight? The Coriolis Effect: the rotation (spinning)

of the Earth on its axis causes deflection of the wind.

Prevailing Wind Patterns

Low latitudes: Easterly Trade WindsBlow towards equator from 30 degrees N and 30 degrees S

Mid-Latitudes: WesterliesHigh Latitudes: Polar easterliesEquator: Windless area called the doldrums

Oceans

Areas located by oceans have more uniform temperatures than areas that are deep in the interior of a continent.

Why??? Water can mix and distribute heat; land can’t. Water is slower to heat up/cool down than land. Marine air/ocean currents regulate the temperatures

year-round.

Ocean Currents

May be warm or coldEither have a cooling effect OR a warming effect on the land they pass

Example: Gulf Stream/North Atlantic Drift current warms western Europe – see map on next slide

Landforms

Orographic Effect: the lifting of an air mass over a large mountain causes a rain shadow on the leeward side of the mountain

Example: Rain Shadow in the Sierra Nevada Mtns in the United States

The Atacama Desert on the western side of the Andes Mtns is the world’s driest desert.

Prevailing winds here are easterlies

Prevailing winds here are westerlies

Atacama Desert in Chile (S. America)