What causes climate ?

Climate•The average year-after-year conditions in a region.

•Determined by the precipitation and temperature of the region.

Precipitation

•The amount of rain or snow that falls in a given region in a year.

•Two factors that determine the amount of precipitation a region receives:

Prevailing windsMountain ranges

Prevailing Winds

•Move the large air masses that create weather patterns.

•Amount of water vapor in the air masses influences the amount of precipitation.

Water Vapor in the Air

•Warm air holds lots of water vapor – humid air.

•Cold air is dry air.

Wind Direction

•Amount of water vapor depends on where the wind comes from. –Winds blowing inland from oceans carry lots of water vapor.

–Winds blowing from land areas carry very little water vapor.

Mountain Ranges

•A mountain range in the path of prevailing winds influences where the precipitation falls.

Windward Side

•The side of the mountain that is hit by the oncoming prevailing winds.

•The side that receives the moisture out of the air.

Leeward Side

•The land on the other side of the mountain.

•This is the cool, dry side of the mountain. •Water in the air has already fallen out.

Temperature

•Helps determine the climate in a region.

•Temperature is influenced by several factors.

Latitude

•Distance of the area above or below the Equator.

•Determines how the sun’s rays strike the surface of the Earth.

Temperature Zones

•Determined by the distance of the area above and below the Equator.

•There are 3 separate zones.

Tropical Zone

•Receives the most direct sunlight at the Equator.•Climate is hot year around.

Temperate Zone•Receives both direct and indirect sunlight due to the tilt of the Earth on its axis.

•Has both cold and warm climates through out the year.

Polar Zone•The sun’s rays striking the Earth with the most indirect rays.

•Area has a cold climate.

Altitude •Distance the area is above

sea level.

•In mountainous regions, altitude is more important than latitude.

•Temperature of the air decreases as the altitude increases.

Distance from Water

•Oceans moderate the temperature of an area.

• Water heats up and cools

down more slowly than the land.

Marine Climates•Have warm winters and cool summers.•Found on the west coasts of North and South America.

Continental Climates

•Areas of land far inland. •Have extreme temperatures.

•Winters are cold and summers are hot.

Ocean Currents

•Currents are streams of water within the oceans that move in regular patterns.

Warm Currents

•Carry warm water from the tropics toward the poles.

•Brings warm air to the land. •Gulf Stream – a warm current that gives England a warm, wet climate.

Cold Currents

•Bring cold water from the poles to the Equator. •Brings cool air to the land they move by. •California Current – a cold

current that flows south from Alaska and makes the West Coast climate cooler than expected.