What is Climate? What is Climate?

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

The climate of any region on the The climate of any region on the Earth is determined by two basic Earth is determined by two basic factors: factors: temperaturetemperature and and precipitationprecipitation. .

Factors that Affect TemperatureFactors that Affect Temperature

Latitude, elevation, and the presence of Latitude, elevation, and the presence of oceans currents are three natural factors oceans currents are three natural factors that affect the temperature at a particular that affect the temperature at a particular location. location.

Latitude is a measure of the distance north Latitude is a measure of the distance north and south and south of the equator. of the equator.

Elevation or altitude, is distance above sea Elevation or altitude, is distance above sea level. As elevation increases, the air level. As elevation increases, the air becomes less dense. As elevation becomes less dense. As elevation increases, the temperature decreases. increases, the temperature decreases.

Ocean currents is a “river” of water Ocean currents is a “river” of water that flows in a definite path in the that flows in a definite path in the ocean. Warm water warms the air ocean. Warm water warms the air and cold water cools the air. So land and cold water cools the air. So land areas near warm water currents have areas near warm water currents have warm temperatures and areas near warm temperatures and areas near cold water currents have cool cold water currents have cool temperatures. temperatures.

Factors That Affect Precipitation Factors That Affect Precipitation

The two natural factors that affect The two natural factors that affect the amount of precipitation at a the amount of precipitation at a particular location are particular location are prevailingprevailing windswinds and and mountain rangesmountain ranges. .

Prevailing Winds is a wind that blows Prevailing Winds is a wind that blows more often from one direction than more often from one direction than from any other direction. These from any other direction. These winds have a great influence on the winds have a great influence on the climate of regions in their path. climate of regions in their path. Different prevailing winds carry Different prevailing winds carry different amounts of moisture. Warm different amounts of moisture. Warm air can hold more moisture than cold air can hold more moisture than cold air. air.

The amount of precipitation at a The amount of precipitation at a particular location is also affected by particular location is also affected by mountain ranges. mountain ranges. A mountain range A mountain range acts as a barrier to prevailing winds.acts as a barrier to prevailing winds.

The The windward side windward side of a mountain, or of a mountain, or

the side facing toward the wind, receives the side facing toward the wind, receives a great deal of precipitation.a great deal of precipitation.

The The leeward sideleeward side of a mountain, or the of a mountain, or the side facing away from the wind receives side facing away from the wind receives little precipitation. little precipitation.

Climate ZonesClimate Zones

The three major climate The three major climate zones on the Earth are the zones on the Earth are the polarpolar, , temperatetemperate, and , and tropicaltropical zones. zones.

Polar ZonesPolar Zones

Polar climates have the coldest Polar climates have the coldest average temperatures. The average average temperatures. The average yearly temperature remains below yearly temperature remains below freezing most of the time. There is freezing most of the time. There is little precipitation in the polar zones. little precipitation in the polar zones.

Temperate ZoneTemperate Zone

In the areas of the temperate zones In the areas of the temperate zones farther from the equator, snow is farther from the equator, snow is common in the winter. The closer to common in the winter. The closer to the equator, rain normally falls all the equator, rain normally falls all year round. year round.

Tropical ZonesTropical Zones

Tropical zones have high Tropical zones have high temperatures and high humidity. temperatures and high humidity. Precipitation in the tropical zones is Precipitation in the tropical zones is usually very heavy during part of the usually very heavy during part of the year. These zones have the warmest year. These zones have the warmest average yearly temperature. average yearly temperature.

Marine and Continental ClimatesMarine and Continental Climates

Within each of the three major Within each of the three major climate zones there are climate zones there are marine marine climatesclimates and and continental continental climatesclimates. .

Areas with marine climate receive Areas with marine climate receive more precipitation. more precipitation.

A continental climate is drier. A continental climate is drier.

The Four SeasonsThe Four Seasons

Most places on the Earth have four distinct Most places on the Earth have four distinct seasons: winter, spring, summer, and seasons: winter, spring, summer, and autumn.autumn.

The different seasons are caused by the The different seasons are caused by the tilt of the Earth’s axis. tilt of the Earth’s axis.

http://www.enchantedlearning.com/subjects/astronomy/planets/earth/Seasons.shtml

Changes in ClimateChanges in Climate

The three natural factors responsible The three natural factors responsible for climate changes are:for climate changes are:

1. The slow drifting of the continents 1. The slow drifting of the continents 2. Changes in the sun’s energy output2. Changes in the sun’s energy output3. Variations in the tilt of the Earth’s 3. Variations in the tilt of the Earth’s

axis and the shape of the Earth’s axis and the shape of the Earth’s orbit.orbit.

http://www.divulgence.net/

Human activities which include an Human activities which include an increased level of carbon dioxide in increased level of carbon dioxide in the atmosphere can also lead to the atmosphere can also lead to changes in climate.changes in climate.