Climate

What is it?

Climate is the name for the general conditions of temperature and precipitation for an area over a long period of time.

What is climate?

The climate of a region is determined by two basic factors:

Temperature Precipitation

Latitude Elevation the presence of ocean currents

Three natural factors that affect the temperature at a particular location are:

Close to the equator, receive the direct rays of the sun.

Direct rays provide most radiant energy.

Near equator climate warm. Polar regions climate cold.

Latitude and climate:

The distance above sea level. As elevation increases, air becomes

thinner (less-dense). Less- dense air cannot hold as much

heat as denser air. So as elevation increases,

temperature decreases.

Elevation or altitude is:

Surface temperature of water affects the temperature above it.

Warm water warms air and cold water cools it.

The Gulf Stream is a warm ocean current along eastern coast of United States.

The California Current travels toward equator carrying cold water along west coast of United States.

Ocean Currents

prevailing winds

mountain ranges

The two factors that affect the amount of precipitation at a particular location are:

Winds more often from one direction than any other.

Influence climate of regions in their path. Different winds carry different amounts

of moisture. Moisture carried by a wind affects

amount of precipitation a region receives. Winds formed by rising warm air tend to

bring precipitation.

Prevailing Winds:

A mountain range acts as a barrier to prevailing winds.

Windward side has wet climate, called the orographic effect.

Leeward side, relatively dry air moves down side and results in very little precipitation, called the rain shadow.

Good example: Great Basin on leeward side of Sierra Nevada Mountain Range.

Mountain Ranges

Earth’s climate can be divided into general climate zones according to average temperatures. The three major climate zones on Earth are:

Polar Temperate Tropical

Climate Zones:

In each hemisphere, the polar zone extends from the pole to about 66.5° latitude. In polar zones, the average yearly temperature is below freezing. The three polar climates are:

Subarctic Tundra Ice cap

Polar Zones

In each hemisphere, the temperate zone is found between 66.5° and 23.5° latitude. The average temperatures range from 41° F to 68° F. The four temperate climates are:

Mediterranean Humid Subtropical Marine West Coast Humid Continental

Temperate Zones

The tropical zones, which extend from 23.5° north and south latitude to the equator, have high temperatures and high humidity. The average temperature during the coldest month of the year does not fall below 64.4° F. The two tropical climates are:

Tropical humid Tropical wet and dry

Tropical Zones

Most are found at about 30 north and south of the equator. Some are in the rain shadow of mountains and some are far in the interior of continents, away from moisture. These regions experience temperature extremes.

Arid Semiarid

Dry climates:

Receives less than 10 in of precipitation a year. Combined effect of prevailing wind’s moisture

content and its direction can make it possible for a desert to exist near a large body of water.

The Sahara Desert is bordered on the west by the Atlantic Ocean. The prevailing winds that blow across the Sahara originate far inland, carry little moisture and are caused by sinking cold air.

Desert

Found all over the world Found in mountains and high plateaus Temperature Range: -2° F to 50° F Change rapidly on mountains, becoming

colder the higher the altitude gets Average Annual Precipitation: 9 in. Very important to temperate zones Work as water storage areas Snow is kept back until spring and summer

when it is released slowly as water through melting

Highland climate