Global Patterns

5.3

Weather Factors

Vocabulary 5.3

Tropical Zone- The area near the equator between about 23.5 degrees north latitude and 23.5 south latitude.

Polar Zone- the areas near both poles from about 66.5 to 90 north and 66.5 to 90 degrees south latitudes.

Temperate Zone- The areas between the tropical and the polar zones.

Windward- The side of a mountain range that faces the oncoming wind.

Leeward- The side of a mountain range that faces away from the oncoming wind.

Jet Streams- Bands of high-speed winds about 10 kilometers above the Earth’s surface.

Monsoon- Sea or land breeze over a large region that changes direction with the seasons.

How Do Global Patterns Affect Local Weather?

Weather changes every day.

Across a local area beachgoers may enjoy a cool day while those living inland may find temperatures higher.

Temperature is affected by: latitude, altitude, distance from large bodies of water, and ocean currents.

Latitude measures the distance of point from the equator, measured in degrees.

Why is the tropical zone warmest temp. zone, and the polar the coldest?

Three Temperature Zones:

Tropical Z., Polar Z., Temperate Z.

How Do Global Patterns Affect Local Weather?

Areas near the equator= have warmer climates than areas far from the equator because the sun’s rays hit Earth’s surface more directly at the equator than at the poles.

•The tropical zone is the area near the equator, between about 23.5° north latitude and 23.5° south latitude.

• Polar zones extend from about 66.5° to 90° north and 66.5° to 90° south latitudes.

•Between the tropical zones and the polar zones are temperate zones. Many mountainous areas have cooler climates than the lower areas around them. In the case of high mountains, altitude is a more important factor than latitude.

Latitude and TemperatureWhat are the three temperature zones on the map?

Global Patterns

How Do Global Patterns Affect Local Weather?

Oceans or large lakes can make temperatures on nearby land less extreme.

Much of the west coasts of North America, South America, and Europe have relatively mild winters and cool summers.

Coastal areas are influenced by ocean currents.

Some warm ocean currents move from the tropics toward the poles, warming the air above the water and nearby land.

Some cold currents move from the polar zones toward the equator, cooling the air and nearby land.

The centers of North America and Asia are too far inland to be warmed or cooled by the ocean. Most of Canada, Russia, and the central United States

reach more extreme temperatures than coastal areas.

Distance from Large Bodies of WaterAlaska is about twice the size of Texas. Factors influencing temperature, such as distance from large bodies of water, affect this big state in different ways.

Global Patterns

Which climate data do you think describe• Juneau? •Fairbanks?

How Do Global Patterns Affect Local Weather?

The main factors that affect precipitation are:

prevailing winds, the presence of mountains, jet streams, and seasonal winds.

•Weather patterns depend on the movement of huge air masses.

• Prevailing winds are those that usually blow in one direction in a region. The amount of precipitation that might fall depends on where the wind blows from.

• A mountain range in the path of prevailing winds can influence where precipitation falls. Rain or snow falls on the windward side of the mountains, the side the wind hits. Little precipitation falls on the land on the leeward side of the mountains—the side the wind does not hit.

How Do Global Patterns Affect Local Weather?

Jet streams narrow bands of high-speed.

•They travel far above Earth’s surface.

•They blow from east to west along the boundary of warm and cold air masses.

•The jet streams can bring warm or cold air across a region and intensify storms.

Monsoons-Sea and land breezes over a large region that change direction with the seasons.

•A seasonal wind patterns affect precipitation.

Currents and TemperatureWarm ocean water warms the air above it. A cold current brings cool air.

Global Patterns

Global PatternsWind and PrecipitationMountains can form a barrier to humid air. What happens to the humid air when it encounters the mountains?

Global Patterns

Jet StreamsWhich arrow shows the polar jet stream on the diagram? Which arrow shows the subtropical jet stream?