11-3 How Is Earths Surface Heated? Lesson Review

Lesson Objectives

Describe how the temperature of the temper changes with altitude.
Outline the properties of the troposphere.
Explicate the role of the ozone layer in the stratosphere.
Describe conditions in the mesosphere.
Explicate how the sun affects the thermosphere.
Identify the exosphere.

Vocabulary

exosphere
mesosphere
ozone
stratosphere
temperature inversion
thermosphere
troposphere

Introduction

Earth'south atmosphere is divided into five major layers. The layers are based on temperature.

Temperature of the Atmosphere

Air temperature changes as distance increases. In some layers of the temper, the temperature decreases. In other layers, information technology increases. Yous tin see this in Figure below and at the link below. Refer to the effigy equally you read about the layers beneath.

How does air temperature alter in the layer closest to Earth?

Troposphere

The troposphere is the everyman layer of the atmosphere. In information technology, temperature decreases with distance. The troposphere gets some of its heat directly from the sun. Virtually, however, comes from Earth's surface. The surface is heated by the sun and some of that heat radiates back into the air. This makes the temperature higher nigh the surface than at college altitudes.

Properties of the Troposphere

Expect at the troposphere in Figure above. This is the shortest layer of the atmosphere. It rises to only nigh 12 kilometers (seven miles) above the surface. Fifty-fifty and then, this layer holds 75 per centum of all the gas molecules in the temper. That's because the air is densest in this layer.

Mixing of Air

Air in the troposphere is warmer closer to World'southward surface. Warm air is less dumbo than absurd air, so it rises higher in the troposphere. This starts a convection prison cell. Convection mixes the air in the troposphere. Rise air is also a main crusade of conditions. All of World'south weather takes identify in the troposphere.

Temperature Inversion

Sometimes air doesn't mix in the troposphere. This happens when air is cooler close to the ground than information technology is above. The cool air is dense, then it stays near the ground. This is called a temperature inversion. An inversion can trap air pollution near the surface. Temperature inversions are more mutual in the wintertime. Can you explain why?

Temperature Inversion and Air Pollution. How does a temperature inversion impact air quality?

Tropopause

At the elevation of the troposphere is a thin layer of air called the tropopause. You lot can see information technology in Figure to a higher place. This layer acts as a barrier. It prevents absurd air in the troposphere from mixing with warm air in the stratosphere.

Stratosphere

The stratosphere is the layer to a higher place the troposphere. The layer rises to almost fifty kilometers (31 miles) above the surface.

Temperature in the Stratosphere

Air temperature in the stratosphere layer increases with altitude. Why? The stratosphere gets near of its heat from the sun. Therefore, it'due south warmer closer to the sun. The air at the bottom of the stratosphere is cold. The cold air is dense, so information technology doesn't ascension. Equally a result, there is footling mixing of air in this layer.

The Ozone Layer

The stratosphere contains a layer of ozone gas. Ozone consists of three oxygen atoms (O₃). The ozone layer absorbs high-energy UV radiation. As yous can run into in Figure beneath, UV radiation splits the ozone molecule. The divide creates an oxygen molecule (O₂) and an oxygen atom (O). This split up releases heat that warms the stratosphere. Past absorbing UV radiation, ozone besides protects Earth's surface. UV radiation would impairment living things without the ozone layer.

How does the ozone layer protect Earth

Stratopause

At the tiptop of the stratosphere is a sparse layer called the stratopause. It acts as a purlieus betwixt the stratosphere and the mesosphere.

Mesosphere

The mesosphere is the layer higher up the stratosphere. Information technology rises to about 85 kilometers (53 miles) above the surface. Temperature decreases with distance in this layer.

Temperature in the Mesosphere

In that location are very few gas molecules in the mesosphere. This ways that there is trivial matter to absorb the sun'south rays and rut the air. Most of the heat that enters the mesosphere comes from the stratosphere below. That's why the mesosphere is warmest at the bottom.

Meteors in the Mesosphere

Did you ever meet a meteor shower, like the 1 in Figure below? Meteors fire every bit they fall through the mesosphere. The space rocks experience friction with the gas molecules. The friction makes the meteors get very hot. Many meteors burn up completely in the mesosphere.

Friction with gas molecules causes meteors to burn upwardly in the mesosphere.

Mesopause

At the elevation of the mesosphere is the mesopause. Temperatures here are colder than anywhere else in the atmosphere. They are every bit low as -100° C (-212° F)! Nowhere on Earth's surface is that cold.

Thermosphere

The thermosphere is the layer above the mesosphere. It rises to 600 kilometers (372 miles) above the surface. The International Space Station orbits World in this layer as in Figure below.

The International Space Station orbits in the thermosphere.

Temperature in the Thermosphere

Temperature increases with altitude in the thermosphere. Surprisingly, it may be higher than one thousand° C (1800° F) near the elevation of this layer! The sunday's energy in that location is very stiff. The molecules absorb the sun's free energy and are heated upwardly. But there are so very few gas molecules, that the air nonetheless feels very cold. Molecules in the thermosphere gain or lose electrons. They so go charged particles called ions.

Northern and Southern Lights

Take yous ever seen a vivid light show in the night sky? Sometimes the ions in the thermosphere glow at nighttime. Storms on the sun energize the ions and make them low-cal up. In the Northern Hemisphere, the lights are called the northern lights, or aurora borealis. In the Southern Hemisphere, they are chosen southern lights, or aurora australis.

Glowing ions in the thermosphere light upwards the nighttime heaven.

Exosphere

The exosphere is the layer above the thermosphere. This is the top of the temper. The exosphere has no real upper limit; it merely gradually merges with outer space. Gas molecules are very far apart in this layer, just they are really hot. Earth'due south gravity is and so weak in the exosphere that gas molecules sometimes merely float off into space.

Lesson Summary

Globe's atmosphere is divided into 5 major layers. The layers are based on temperature.
The troposphere is the everyman layer. Temperature decreases with altitude in this layer. All atmospheric condition takes place hither.
The stratosphere is the layer above the troposphere. Temperature increases with altitude in this layer. The ozone layer occurs here.
The mesosphere is the layer in a higher place the stratosphere. Temperature decreases with altitude in this layer. Meteors burn upward here.
The thermosphere is the layer in a higher place the mesosphere. Temperature increases with distance in this layer. The northern and southern lights occur hither.
The exosphere is the highest layer. Air molecules are very far apart. They may escape World'south gravity and float into infinite.

Lesson Review Questions

Remember

1. How does temperature change in the troposphere?

2. What is a temperature inversion?

3. Why is the ozone layer in the stratosphere of import to life on Earth?

4. Where does the mesosphere go its heat?

Employ Concepts

v. Recollect of a creative way you could model the layers of the atmosphere. Describe your model. How does it bear witness temperature differences between the layers?

Think Critically

6. How is a temperature inversion similar the temperatures of the stratosphere and troposphere?

seven. Explain why air mixes in the troposphere but not in the stratosphere.

viii. Why is in that location a hole in the ozone layer? What do y'all think the consequences of that hole are?

Points to Consider

Free energy from the dominicus is responsible for winds that accident in the troposphere.

What is wind?
How does energy cause winds to blow?

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Source: https://sites.google.com/site/earthscienceinmaine/layers-of-the-atmosphere