LACEMOP Factors that Shape Weather

Weather & Climate Weather : a condition of the atmosphere in one place during a short period of time Climate : weather patterns typical for an area over a long period of time

Latitude The influence of latitude on climate is part of the Earth-Sun Relationship  The sun’s direct rays fall upon Earth in a regular pattern  This pattern correlates w/ Latitude Zones  Within each zone, the climate follows general patterns

Earth-Sun Relationships

Air Masses Air masses take on the “weather” of the place from which they came. -a front — most weather changes are caused by these. -Convectional Precipitation: - Typical of hot climates - Convection occurs after morning sunshine heats warm, moist air. Clouds form in the afternoon and the rain falls.

Fontal Precipitation — when 2 fronts of different temperatures meet. Warm air forced upward by heavier, cool air. Rising warm air cools = precipitation Most common type

Continentality Large bodies of water have a moderating effect on land temperatures. Why? Land and water absorb and store energy at different rates. Land changes quickly — water more slowly. Opposite air blows off the water and moderates land temperature.

Elevation -The earth’s atmosphere thins as altitude increases. Thus: as elevation increases, temperature decreases ~ b/c thinner air retains less heat. - Even in sunny places, mountains are cold, snowy places year-round.

Mountain Barriers Can block air masses & cause precipitation.

Mountain Barriers Orographic Precipitation : warm moist air forced upward when passing over a mountain. Warm winds cool as they rise over the mountains and clouds form. Windward : mountain side which faces the ocean Leeward : mountain side which is in a “rain shadow” (no precipitation received) Air is warm and dry on the Leeward side

Ocean Currents Help to distribute heat Carry warm water from tropics to poles and return cold water to the Equator Winds affect current movement Air masses take on water temperature

Trade winds -- blow from the northeast toward the Equator and from the southeast toward the equator Wind Patterns

Westerlies – prevailing winds in the mid-latitudes blow diagonally west to east Wind Patterns

Polar Easterlies – blow diagonally in the high latitudes east to west—pushing the cold air toward the mid latitudes Wind Patterns

Pressure & Wind Wind moves high to low Movement from equator to poles and back Rising warm air = low pressure Falling cool air = high pressure

Wind Patterns Coriolis Effect: rotation of the earth bends the patterns of the wind