How Oceans and Mountains Affect Weather and Climate

TCAP CoachChapter 3Lesson 14

How Oceans and Mountains Affect Weather and Climate

➲ Objectives:➲ Describe the effects of the ocean on

weather and climate.➲ Explain how mountains affect weather and

climate

How Oceans and Mountains Affect Weather and Climate

➲ Year after year, the average daily temperature in July for Nashville is about 80.6oF. In Phoenix, Arizona, it is about 89.6oF. The usual rainfall in Nashville over a year is about 44.9 inches. In Phoenix it is only about 7.3 inches. Why is Phoenix warmer and drier than Nashville?

➲ In this lesson, you will explore some factors that affect temperature and rainfall in different locations.

Climate and Weather

➲ Weather is the condition of the air at a certain time and place.

➲ The weather where you live can change from hour to hour, or day to day. But the climate stays the same for many years.

➲ Climate is the average weather of a place over a long period of time. For example, the climate in Tennessee is not too cold or too hot, too dry or too wet. But at any particular time, the weather might be cold, hot, dry, or wet.

Climate and Weather

➲ Another example: The climate of many deserts, such as those in Arizona, is hot and dry. But on some days rain may fall. And the temperature may be cool at times. A passing wet or cool day in a desert is its weather. Its general dryness and hotness is its climate.

Climate and Weather

➲ The climate of an area can be dry and cold, like the climate of Antarctica.

➲ The climate can be dry and warm, like the climate in the southwestern part of the United States and in the Sahara Desert in northern Africa.

➲ The climate can be wet and cool, like the climate in England, Scotland, Ireland, and parts of the northwestern United States.

➲ The climate can also be wet and warm, like in the Amazon rain forest in South America.

Climate and Weather

➲ In general, areas closer to Earth’s poles are cooler than areas closer to Earth’s equator. For example, the climate in Tennessee is much warmer than the climate in Alaska. Alaska is closer to the North Pole than Tennessee. Tennessee is closer to the equator than Alaska.

➲ Climate does not depend just on distance from the equator. Mountains and oceans also affect weather and climate.

Climate and Weather

Mountains

➲ Mountains affect temperature.➲ In general, high places have cooler

temperatures than lower places.➲ The air near Earth’s surface tends to get

cooler the higher you go. ➲ Mountains also affect rainfall.➲ Think of warm, wet air moving toward a

mountain. The shape of the mountain forces the air to move upward. As the air moves up, it cools.

Mountains

➲ Now, the cool air cannot hold as much moisture as warm air, so the moisture forms tiny water droplets.

➲ The droplets come together to form larger droplets.

➲ When they get heavy enough, they fall as rain.

➲ Most of the water falls out of the air on this side of the mountain.

Mountains

➲ The air that moves over the top of the mountain is cool and dry.

➲ This cool, dry air sinks down the other side.➲ Places on this side of the mountain tend to

have a cool, dry climate.➲ The diagram on the next slide shows this

rain shadow effect.

Mountains

Oceans

➲ Places near oceans often have mild climates.➲ This is because water takes in heat more slowly

than land.➲ Water also releases heat more slowly than land.➲ In summer, ocean water tends to stay cool. The

water keeps the air above the water and nearby land cool.

➲ In winter, the water slowly releases heat. This heat keeps the air above the water and nearby land warmer.

Oceans

➲ The climate of a place is also affected by ocean currents.

➲ An ocean current is a stream of water that flows through an ocean.

➲ Some currents are warm. Other currents are cool.

➲ Warm currents generally flow away from the equator. Cool currents generally flow away from Earth’s poles.

Oceans

➲ The Gulf Stream is a warm current that flows around the tip of Florida from the Gulf of Mexico.

➲ It moves northward along the East Coast of North America.

➲ Then the gulf stream turns eastward toward Europe.

➲ This current produces a warmer climate in England and Ireland than would be usual for places so far north of the equator.

Oceans

➲ On the other side of the United States, a cold current called the California Current flows southward along the West Coast.

➲ This current keeps much of the coast cooler than it would otherwise be.

1. Temperatures in mountain areas tend to be

➲ A. lower than in valley areas➲ B. higher than in valley areas➲ C. the same as in valley areas➲ D. higher than in areas near oceans

1. Temperatures in mountain areas tend to be

➲ A. lower than in valley areas

2. Which of the following statements is TRUE?

➲ A. Water heats and cools faster than land.➲ B. Land heats and cools more slowly than

water.➲ C. Water heats and cools more slowly than

land.➲ D. Water and land heat and cool at the

same rate.

2. Which of the following statements is TRUE?

➲ C. Water heats and cools more slowly than land.

3. Warm, wet air moves up a mountain. What kind of air will move down the

other side?

➲ A. cool, dry air➲ B. cool, wet air➲ C. warm, dry air➲ D. warm, wet air

3. Warm, wet air moves up a mountain. What kind of air will move down the

other side?

➲ A. cool, dry air