Chapter 17 Earth Science

What are two ways that humans are adding greenhouse gases to the atmosphere?

* The main sources of greenhouse gases due to human activity are: burning of fossil fuels and deforestation leading to higher carbon dioxide concentrations in the air.

What type of heat transfer is most responsible for the heating of Earth's surface?

*Heat from the Earth's core and radiation from the Sun is transferred to the surface of the Earth by conduction. Contact of the atmosphere with these warm surfaces transfers thermal energy, which then heats up the rest of the air through convection. RADIATION

Which two gases combine to make-up 99% of the gases in the atmosphere?

*Nitrogen and oxygen are the main components of the atmosphere by volume. Together these two gases make up approximately 99% of the dry atmosphere.

Why are some gases in our atmosphere referred to as selective absorbers?

*The gases of our atmosphere are known as "selective absorbers" of radiant energy. That is, a particular gas absorbs and emits energy well at some wavelengths but not at others.

What is the greenhouse effect?

*The greenhouse effect is defined as when the Earth's atmosphere becomes thick with gases and substances which trap the sun's radiation, making the Earth warmer. An example of the greenhouse effect is global warming.

What are greenhouse gases and what role do they play in the atmosphere?

*The greenhouse gases absorb some of this energy and radiate much of it back towards the surface whilst the rest is radiated out to space. This plays an important role in keeping the Earth's surface warm and able to sustain life. Greenhouse gases include water vapour (H2O), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), ozone and halocarbons.

What are variable gases? Give two examples.

*The so called "variable gases" are those present in small and variable amounts. These include carbon dioxide, methane, ozone, water vapor, and particulates among others. Even though they represent a tiny portion of the atmosphere as a whole, they exert a great control over our environment.

What is wind and how does the unequal heating and cooling of Earth's surface cause wind?

*The uneven heating of Earth's surface produces wind because the air temperature and air pressure are different. The differences in the air causes the air to a lower pressure. The movement of this is wind. Uneven heating of the Earth's surface produces air masses of different temperatures.

What is the atmosphere?

All of the gasses that surrounds us. *The envelope of gases surrounding the earth or another planet.

Why does temperature increase with height within the stratosphere?

Because the ozone layer is in the stratosphere so the higher up you go the closer you get to it and because the ozone absorbs heat it is hot/warm. *In the stratosphere, temperature increases with altitude. The reason is that the direct heat source for the stratosphere is the Sun. A layer of ozone molecules absorbs solar radiation, which heats the stratosphere.

What are CFC's and why are they discussed in Meteorology?

Chlorofluorocarbons, commonly known as CFCs, are a group of man-made compounds containing chlorine, fluorine and carbon. Their long lifetimes in the atmosphere mean that some end up in the higher atmosphere (stratosphere) where they can destroy the ozone layer, thus reducing the protection it offers the earth from the sun's harmful UV rays.

Which type of heat transfer only occurs at the lowest level of the atmosphere where the gases are touching Earth's surface?

Conduction

What type of heat transfer is most responsible for the heating of the atmosphere?

Convection

Explain how conduction, convection, and radiation transfer heat.

Heat can be transferred from one place to another by three methods: conduction in solids, convection of fluids (liquids or gases), and radiation through anything that will allow radiation to pass. The method used to transfer heat is usually the one that is the most efficient. *Convection is heat transfer by mass motion of a fluid such as air or water when the heated fluid is caused to move away from the source of heat, carrying energy with it. *Heat can be transferred by infrared radiation. Unlike conduction and convection, which need particles, infrared radiation is a type of electromagnetic radiation that involves waves. *A good example would be heating a tin can of water using a Bunsen burner. Initially the flame produces radiation which heats the tin can. The tin can then transfers heat to the water through conduction. The hot water then rises to the top, in the convection process.

Why is ozone an important gas in the atmosphere?

It helps absorb radiation from the sun. *Ozone is a gas in the atmosphere that protects everything living on the Earth from harmful ultraviolet (UV) rays from the Sun. Without the layer of ozone in the atmosphere, it would be very difficult for anything to survive on the surface.

Give two examples of selective absorbers and explain why they are considered selective absorbers.

Selective absorbers in the atmosphere, such as water vapor and carbon dioxide, absorb some infrared radiation from the earth and radiate a portion of it back to the surface, producing the atmospheric greenhouse effect.

Which layer of earth's atmosphere is the highest concentration of ozone found in?

Stratosphere * The stratospheric region with the highest ozone concentration is commonly known as the "ozone layer"

What is the difference between temperature and heat?

Temperature is the measure of how much heat an object is giving off while heat is the energy of an object. *The hotter an object is, the faster the motion of the molecules inside it. Thus, the heat of an object is the total energy of all the molecular motion inside that object. Temperature, on the other hand, is a measure of the average heat or thermal energy of the molecules in a substance.

Why is carbon dioxide an important gas in our atmosphere?

The carbon dioxide traps the Earth's heat like a blanket. *Carbon dioxide is an important greenhouse gas that helps to trap heat in our atmosphere. Without it, our planet would be inhospitably cold.

Discuss how altitude, latitude, surface composition, the tilt of the Earth's axis, etc., affect surface temperatures on Earth's surface.

The higher the altitude, the colder, the more direct the sun's rays based on the tilt, water vs land(Water reflects more than land and takes longer to heat up than land so its colder near water

How do temperature and pressure change with height in the troposphere?

The higher up you go, the thinner the air and becomes colder. *Higher up in the troposphere, where less heat from the surface warms the air, the temperature drops. Gravity of the earth holds our atmosphere close to the surface, so the density (and pressure) of air gets gradually lower as you go to higher altitude.

In which layer of the atmosphere does most weather occur in?

Troposphere * The troposphere is the first layer above the surface and contains half of the Earth's atmosphere. Weather occurs in this layer.

Which layer of Earth's atmosphere is closest to Earth's surface?

Troposphere *The troposphere is the first layer above the surface and contains half of the Earth's atmosphere. Weather occurs in this layer.

What is air?

gaseous mixture that makes up the Earth's atmosphere * The invisible gaseous substance surrounding the earth, a mixture mainly of oxygen and nitrogen.