What Causes the Temperature to Increase With Height Through the Stratosphere

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Lesson Objectives

List the major layers of the atmosphere and their temperatures.
Discuss why all weather takes identify in the troposphere.
Discuss how the ozone layer protects the surface from harmful radiation.

Vocabulary

aurora
exosphere
inversion
ionosphere
magnetosphere
mesosphere
ozone layer
solar current of air
stratosphere
temperature gradient
thermosphere
troposphere

Introduction

The atmosphere is layered, corresponding with how the temper'southward temperature changes with altitude. Past understanding the manner temperature changes with altitude, we can learn a lot about how the atmosphere works. While atmospheric condition takes place in the lower temper, interesting things, such equally the cute aurora, happen higher in the temper.

Air Temperature

Papers held up by rising air currents above a radiator demonstrate the important principle that warm air rises.

Why does warm air ascension (Figure above)? Gas molecules are able to move freely and if they are uncontained, every bit they are in the atmosphere, they tin can take upward more or less space.

When gas molecules are cool, they are sluggish and do non accept up as much space. With the same number of molecules in less space, both air density and air pressure level are college.
When gas molecules are warm, they movement vigorously and accept up more space. Air density and air pressure are lower.

Warmer, lighter air is more than buoyant than the cooler air above it, so information technology rises. The cooler air then sinks down, considering it is denser than the air beneath it. This is convection, which was described in the Plate Tectonics chapter.

The property that changes nearly strikingly with altitude is air temperature. Different the change in force per unit area and density, which decrease with altitude, changes in air temperature are non regular. A change in temperature with distance is called a temperature slope.

The atmosphere is divided into layers based on how the temperature in that layer changes with altitude, the layer'south temperature gradient (Effigy below). The temperature slope of each layer is different. In some layers, temperature increases with altitude and in others it decreases. The temperature gradient in each layer is determined by the heat source of the layer (Figure below).

The four main layers of the temper accept different temperature gradients, creating the thermal structure of the atmosphere.

The layers of the temper announced as different colors in this image from the International Space Station.

Most of the important processes of the atmosphere take place in the lowest 2 layers: the troposphere and the stratosphere.

Troposphere

The temperature of the troposphere is highest near the surface of the Earth and decreases with altitude. On average, the temperature slope of the troposphere is half-dozen.v°C per 1,000 m (3.half-dozen°F per 1,000 ft.) of altitude. What is the source of estrus for the troposphere?

Earth's surface is a major source of heat for the troposphere, although nearly all of that rut comes from the Sun. Stone, soil, and water on World absorb the Sun's calorie-free and radiate it dorsum into the temper equally heat. The temperature is also higher near the surface because of the greater density of gases. The higher gravity causes the temperature to rise.

Detect that in the troposphere warmer air is below cooler air. What do you think the consequence of this is? This condition is unstable. The warm air about the surface rises and cool air higher in the troposphere sinks. And then air in the troposphere does a lot of mixing. This mixing causes the temperature slope to vary with time and place. The rising and sinking of air in the troposphere ways that all of the planet'southward weather takes identify in the troposphere.

Sometimes there is a temperature inversion, air temperature in the troposphere increases with distance and warm air sits over common cold air. Inversions are very stable and may concluding for several days or even weeks. Inversions class:

Over state at night or in winter when the ground is cold. The common cold ground cools the air that sits in a higher place information technology, making this low layer of air denser than the air to a higher place it.
Near the coast where cold seawater cools the air to a higher place it. When that denser air moves inland, it slides beneath the warmer air over the country.

Since temperature inversions are stable, they often trap pollutants and produce unhealthy air conditions in cities (Figure below).

Smoke makes a temperature inversion visible. The fume is trapped in cold dense air that lies beneath a cap of warmer air.

At the elevation of the troposphere is a thin layer in which the temperature does not modify with height. This ways that the libation, denser air of the troposphere is trapped beneath the warmer, less dense air of the stratosphere. Air from the troposphere and stratosphere rarely mix.

A science experiment that clearly shows how a temperature inversion traps air, forth with whatever pollutants are in information technology, near the ground is seen in this video (5c): http://www.youtube.com/watch?v=LPvn9qhVFbM (two:50).

Stratosphere

Ash and gas from a large volcanic eruption may burst into the stratosphere, the layer above the troposphere. One time in the stratosphere, information technology remains suspended in that location for many years because there is so little mixing between the two layers. Pilots like to fly in the lower portions of the stratosphere considering there is little air turbulence.

In the stratosphere, temperature increases with altitude. What is the estrus source for the stratosphere? The direct heat source for the stratosphere is the Sun. Air in the stratosphere is stable because warmer, less dense air sits over cooler, denser air. As a result, there is niggling mixing of air within the layer.

The ozone layer is establish within the stratosphere between 15 to 30 km (9 to 19 miles) distance. The thickness of the ozone layer varies by the flavor and too by breadth.

The ozone layer is extremely of import considering ozone gas in the stratosphere absorbs most of the Dominicus'southward harmful ultraviolet (UV) radiations. Because of this, the ozone layer protects life on World. Loftier-energy UV light penetrates cells and damages Deoxyribonucleic acid, leading to jail cell expiry (which we know as a bad sunburn). Organisms on Globe are not adjusted to heavy UV exposure, which kills or damages them. Without the ozone layer to reflect UVC and UVB radiation, well-nigh complex life on Globe would not survive long (Figure below).

Even with the ozone layer, UVB radiation still manages to reach Earth's surface, peculiarly where solar radiation is loftier.

Mesosphere

Temperatures in the mesosphere decrease with altitude. Because at that place are few gas molecules in the mesosphere to absorb the Sunday'due south radiation, the rut source is the stratosphere below. The mesosphere is extremely common cold, especially at its tiptop, near -90°C (-130°F).

The air in the mesosphere has extremely low density: 99.9% of the mass of the atmosphere is below the mesosphere. Every bit a outcome, air pressure is very low (Figure beneath). A person traveling through the mesosphere would feel severe burns from ultraviolet light since the ozone layer which provides UV protection is in the stratosphere below. In that location would be almost no oxygen for breathing. Stranger yet, an unprotected traveler'south blood would boil at normal body temperature because the pressure is and so depression.

Meteors burn in the mesosphere even though the gas is very thin; these burning meteors are shooting stars.

Thermosphere and Beyond

The International Space Station (ISS) orbits inside the upper part of the thermosphere, at about 320 to 380 km above the World.

The density of molecules is so low in the thermosphere that one gas molecule tin can get nigh 1 km before information technology collides with some other molecule. Since so lilliputian energy is transferred, the air feels very cold (Effigy to a higher place).

Within the thermosphere is the ionosphere. The ionosphere gets its name from the solar radiation that ionizes gas molecules to create a positively charged ion and one or more than negatively charged electrons. The freed electrons travel within the ionosphere as electrical currents. Considering of the free ions, the ionosphere has many interesting characteristics.

At night, radio waves bounce off the ionosphere and back to Globe. This is why you tin can often pick up an AM radio station far from its source at night.

The Van Allen radiation belts are 2 doughnut-shaped zones of highly charged particles that are located beyond the atmosphere in the magnetosphere. The particles originate in solar flares and fly to Earth on the solar wind. Once trapped by Earth's magnetic field, they follow forth the field's magnetic lines of force. These lines extend from above the equator to the North Pole and too to the Due south Pole so render to the equator.

When massive solar storms cause the Van Allen belts to become overloaded with particles, the consequence is the most spectacular feature of the ionosphere — the nighttime aurora (Figure below). The particles spiral along magnetic field lines toward the poles. The charged particles energize oxygen and nitrogen gas molecules, causing them to light upward. Each gas emits a particular colour of lite.

(a) Spectacular lite displays are visible as the aurora borealis or northern lights in the Northern Hemisphere. (b) The aurora australis or southern lights encircles Antarctica.

There is no real outer limit to the exosphere, the outermost layer of the temper; the gas molecules finally become and then deficient that at some point in that location are no more. Beyond the atmosphere is the solar wind. The solar wind is made of loftier-speed particles, mostly protons and electrons, traveling speedily outward from the Sun.

This video is very thorough in its give-and-take of the layers of the temper. Call up that the chemical limerick of each layer is virtually the same except for the ozone layer that is found in the stratosphere (8a): http://www.youtube.com/sentry?v=S-YAKZoy1A0 (vi:44).

KQED: Illuminating the Northern Lights

What would Earth'south magnetic field await similar if it were painted in colors? It would look like the aurora! This QUEST video looks at the aurora, which provides clues about the solar air current, World's magnetic field and World's atmosphere. Learn more at: http://scientific discipline.kqed.org/quest/video/illuminating-the-northern-lights/.

Lesson Summary

Features of the temper modify with altitude: density decreases, air pressure level decreases, temperature changes vary.
Different temperature gradients create different layers inside the atmosphere.
The lowest layer is the troposphere where well-nigh of the atmospheric gases and all of the planet's weather condition are located. The troposphere is heated from the ground, then temperature decreases with distance. Because warm air rises and cool air sinks, the troposphere is unstable.
In the stratosphere, temperature increases with altitude. The stratosphere contains the ozone layer, which protects the planet from the Sun'southward harmful UV radiation.

Review Questions

Give a detailed explanation of why warm air rises.
Why doesn't air temperature alter uniformly with distance? Give examples.
Describe how the ground acts as the heat source for the troposphere. What is the source of energy and what happens to that energy?
How stable is an inversion and why? How does an inversion form?
Phoenix, Arizona, is a city in the Southwestern desert. Summers are extremely hot. Winter days are ofttimes adequately warm but winter nights tin be quite chilly. In Dec, inversions are quite common. How does an inversion form under these conditions and what are the consequences of an inversion to this sprawling, car-dependent city?
Why tin't air from the troposphere and the stratosphere mix freely?
What is the oestrus source for the stratosphere? How is that heat absorbed?
Describe ozone creation and loss in the ozone layer. Does ane occur more than than the other?
How and where are "shooting stars" created?
Why would an unprotected traveler's blood boil in the mesosphere?

Points to Consider

How does solar energy create the atmosphere's layers?
How does solar energy create the weather condition?
What would happen to life on Earth if in that location was less ozone in the ozone layer?

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Source: https://courses.lumenlearning.com/sanjac-earthscience/chapter/atmospheric-layers/

Holcomb Buthich