Chapter 22

Atmospheric Forces

• A total eclipse of the Moon occurs during the night of Wednesday, February 20/21, 2008.

• The entire event is visible from South America and most of North America (on Feb. 20) as well as Western Europe, Africa, and western Asia (on Feb. 21).

• During a total lunar eclipse, the Moon's disk can take on a dramatically colorful appearance from bright orange to blood red to dark brown and (rarely) very dark gray.

• An eclipse of the Moon can only take place at Full Moon, and only if the Moon passes through some portion of Earth's shadow.

• The shadow is actually composed of two cone-shaped parts, one nested inside the other. The outer shadow or penumbra is a zone where Earth blocks some (but not all) of the Sun's rays.

• In contrast, the inner shadow or umbra is a region where Earth blocks all direct sunlight from reaching the Moon.

• During the five millennium period from 2000 BC through AD 3000, there are 7,718 eclipses[1] of the Moon (including both partial and total eclipses).

• From 0 to 3 lunar eclipses (partial or total) occur each year. The last time three total lunar eclipses occurred in one calendar year was in 1982.

• On average, partial eclipses slightly outnumber total eclipses by 7 to 6[2].

• The last total lunar eclipse visible from the entire continental United States occurred on August 28, 2007. North Americans will have their next opportunity to see a total lunar eclipse on 2010 Dec 21.

Complete the following assignments on your own

paper.

Number each response clearly as you go.

Chapter 22 page 547

• Section 1

• 1. Preview the chapter by looking at all of the pages of the chapter.

• 2. What is the atmosphere?

• The layers of gases that surround the earth make up the atmosphere

2. What is the atmosphere?

• 3. Describe what is found in the atmosphere of Earth and draw the pie graph of the composition of earth’s atmosphere.

78% Nitrogen

21% Oxygen

<1% Argon

.1% other gases

• 4. Describe where each of the main gasses come from.

• 78% Nitrogen nitrogen cycle

• air to

• nitrogen in the ground ( by nitrogen fixing bacteria)

• then into plants and animals

• Then back to the soil by waste products

• Bacteria that decay return the nitrogen to the air

Nitrogen Cycle

Oxygen 21%• Living things ( respiration) and forest fires

remove oxygen from the air

• Land and ocean plants and algae replace the oxygen by photosynthesis.

• The amount used equals the amount produced so..

• The percent

• remains 21

Oxygen cycle

Air molecules move!

• 5. What factors determine how much water vapor is in the air?

5. What factors determine how much water vapor is in the air?

• Time of day

• Location

• Season

• Water vapor comes from evaporation of lakes, ocean etc and from transpiration

• 6. What is ozone?

• 7. What does ozone do for us here on earth? How are levels of ozone changed?

= O3

7. What does ozone do for us here on earth? How are levels of ozone changed?

• Ozone absorbs harmful ultraviolet light

• CFC’s break down ozone and weaken the layer that protects us.

• Ozone is a colorless, highly reactive gas with a distinctive odor.

• It is formed naturally by electrical discharge (lightning) and in the upper atmosphere at altitudes of between 15 to 35km.

• Stratospheric ozone protects the Earth from harmful ultraviolet radiation from the sun. 

8. What are particulates? Where do they come from?

• Solid particles in the atmosphere.

• Sources:

• Ash

• Microscopic organisms

• Mineral particles

• Pollen

• Meteor particles

• salt

• 8. What are particulates? Where do they come from?

9. What is atmospheric pressure?

• 9. What is atmospheric pressure?

• The pressure exerted on a surface from the atmosphere equally in all directions.

• We have the pressure of the 80 miles of air above us

• which is 15 pounds per square inch.

We don't feel the

weight of air

• nor do balloons seem heavy.  

• the same volume, air is lighter than liquid or solids.  

• But there are many miles of air above us pushing down with incredible weight.

Air gets heavier as it cools.

• For example, sometimes rain falling in a thundercloud cools the air fast and the heavy air comes crashing downward about 45 miles per hour.

• Atmospheric pressure decreases as altitude increases

• Temperature and water vapor also change the pressure.

• Suction cups are an example of air pressure at work!

• any time air gets squeezed out from between two objects, they will be held together by air pressure.

• If you've ever walked through mud, you noticed how hard it is to lift your feet. That's not because mud is sticky or thick. It's because air gets squeezed out from between your shoes and the mud. Air pressure will try to hold your feet and shoes down.

Drinking through a Straw

• One clue to understanding this is to notice what happens to the cheeks of people drinking through a straw.

• when you drop your jaw and keep your lips closed, there's more room for the air to spread out. The air molecules are now spread out over a larger volume, so fewer are now striking each square inch of the inside of the mouth;

• so the air pressure inside the

• mouth is less

• This pushes on

• the cheeks

• causing them

• to be sunken.

• 10. What causes earth to have an atmosphere?

•GRAVITY

• 11. What are the three units used to measure atmospheric pressure?

• Atmospheres (atm)

• Mm or inches of mercury

• Millibars (mb)

• Standard atmospheric pressure =

1 atmosphere or

760 mm or

1000 mb

• 12. What are the two types of instruments used to measure air pressure?

• Mercurial barometer Aneroid barometer

• 13. Draw a diagram of the layers of the atmosphere. Page 552

• 14. Briefly describe each of the layers.

Troposphere: layer closest to earth, most all weather occurs here, most water vapor and CO2,temp decreases with height 6.5 degrees per km.

At 12 km high

temp stops

decreasing

= tropopause

StratosphereAbove tropopause, temp at lowest is -600C

temp increases with height and rises to 00C

the warmest of this

layer represents

the stratopause

Most all ozone

is in the

stratosphere

AIRPLANES NOT ALLOWED

Very few airplanes can fly as high as the stratosphere because the air is so thin that there is not enough lift to keep the aircraft supported.

Some spy planes do fly in the lower stratosphere,

such as the U-2 and the SR-71.

Mesosphere and Thermosphere

Temp decreases as height increases

Average temp -900C

coldest in the atmosphere

mesopopause

Temp increases steadily! Up to 1,000 0C

15.What is a temperature inversion? When and where do they occur?

• The situation of having warm air on top of cooler air is referred to as a temperature inversion, because the temperature profile of the atmosphere is "inverted" from its usual state.

• Conditions that favor the development of a strong surface inversion are calm winds, clear skies, and long nights. Since the nights in the wintertime are much longer than nights during the summertime, surface inversions are stronger and more common during the winter months.

• Normally the air gets cooler as we go higher,

• but sometimes the air near the ground is colder than the air above it.

• Because cold air is heavier, it will stay close to the ground.

• This traps pollutants.

• This condition is common in Phoenix in the winter and results in the infamous brown cloud.

Section2 page 555• 1. What is radiation?

All forms of

energy that

travel through

space as

waves.

2. What are the forms of radiation found in the

electromagnetic spectrum?

3. Draw a diagram of what happens to the solar radiation

that hits the earth. P556absorbed, scattered, or reflected

• 4. Read the section on Ozone.

• What problems would occur if the ozone layer is broken down?

• What do we think is responsible for destroying the ozone layer?

Damage to DNA and skin cancer would increase

CFC’s destroy the ozone

5. What types of things cause the radiation to scatter?

• Scattering occurs when particles like clouds , dust, water droplets or large gas molecules present in the atmosphere interact with and cause the electromagnetic radiation to be redirected from its original path.

6. What determines if radiation is absorbed or reflected?

• Color• Texture• Composition• Volume• Mass• Transparency• State of matter• Specific heat Of the material

• 7. Shorter wave lengths hit the earth and they do what?

• Change to longer wavelengths

• 8. Read about the greenhouse effect. What is a greenhouse?

• How is the earth like one?

A building made of glass or plastic to trap the warmth of the sun to grow plants even when it is cold!

9. How do humans affect the greenhouse effect?

Humans add carbon dioxide by burning fossil fuels

This may increase the

greenhouse effect

causing the climates

to change

10. When are the warmest hours of the day? Why?

• Late afternoon

11. How does latitude affect temperatures?

Lower latitudes have warmer temperatures

The more direct the sun’s rays the less they spread and the greater the intensity!

12. How does the season affect the temperatures?

13. How does having water vapor in the air change the

temperatures?• Water vapor stores heat

• Less vapor -----------less heat held

• Dry areas have large ranges of temperatures from day to night

• More vapor-----------more heat retained

• Smaller fluctuations in the daytime and evening temperatures.

14. What is conduction?

Transfer of energy as heat through a material

15. What is convection?

Movement of matter due to differences in density caused by temperature variations

16. What is radiation?

• The transfer of heat through air, without contact!

Section 3 page 561

• 1. What causes movement of the world wide air?

• Pressure differences

• From high pressure to low pressure

• From the poles toward the equator

• If the earth did not rotate, and was completely flat on the surface, the air would circulate in the following pattern:

2. What is the Coriolis Effect?

• The curving of the path of a moving object from an otherwise straight path due to Earth’s rotation

• http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/gifs/coriolis.mov

• Deflection of winds also provides evidence of the Earth’s rotation. Winds blow from an area of high pressure to an area of low pressure but in the Northern hemisphere the winds are deflected to the right, in the southern hemisphere the winds deflect to the left.

• The Coriolis effect is due to the motion of the Earth.

• A “handy” way to remember Coriolis force: • Put out your right hand, palm up. The direction of motion is the direction in

which your fingers are pointing. Now, stick out your thumb as far as it will go away from your palm. This is the direction of the Coriolis deflection. If your right hand is facing up, this is how the Coriolis deflection will act upon a moving object in the Northern Hemisphere (to the right). If you flip your right hand over, palm down, this is the way the deflection will be in Southern Hemisphere (to the left).

• So, right hand up (northern), deflection is to the right.

• Right hand down (southern), deflection is to the left.

• The Coriolis Effect causes winds in the northern hemisphere to blow clockwise around a high pressure area.

•

• H

• Winds blow counter-clockwise around a low pressure area.

• L

• Winds in the northern hemisphere turn right relative to the earth’s surface.

• Winds in the southern hemisphere turn left relative to the earth’s surface.

• The Coriolis Effect is not a true force but it acts like one to the observer

• 3. Winds blow from areas of high pressure to areas of what pressure?

• Lower pressure

• Wind results from uneven heating of the earth’s atmosphere.

• Wind moves from higher to lower pressure areas.

• H L

• 4. What are convection cells and how do they relate to wind belts?

• A looping pattern of air flow

• 5. Draw the diagram on page 562 showing the wind belts.

• Because the earth rotates on its 23.5 degree axis, the Coriolis Effect causes the winds to turn eastward.

• Three pairs of circulation cells show up from the equator to the poles.

Draw a picture of the three Draw a picture of the three circulation beltscirculation belts

• At 30 degrees north and south latitudes the winds are almost due East.

• The doldrums is the name of the low pressure belt at the equator.

• Horse latitudes are located at the high pressure belt at 30 degrees north and south latitude.

• Low pressure at the equator, high at 30 degrees, low at 60 degrees and high at the poles.

L

HL

H

• The doldrums are hot and humid with no winds.

Trade winds blow between the doldrums and the horse latitudes.

The horse latitudes are dry and have little wind

The sub polar pressure belt is cold and stormy

Trade winds are warm and steady

Prevailing westerlies are irregular.

• 6. What is the jet stream and how does it change our weather?

• A narrow band

of strong

winds that blow

in the upper troposphere.

• Polar jet streams bring cold polar air and steer storms and fronts

• Subtropical jet streams where warm tropical air meets cooler air

7. What are local winds?

• Winds that are not part of the global wind belts and occur on a much smaller scale.

• Less then 100 km and gentle they are called a breeze

• 8. What is a sea breeze and why does it happen?

• The breeze flows in reverse directions during the day and night.

• 9. What is a mountain breeze and why does it happen?

• Mountain winds are local winds caused by the cold air from the mountain tops falling into the low, valley areas at night.

• • During the day, the warm mountain air

rises up and a breeze blows up from the valley. A valley wind.

Mountain windnight time

• Cold air drops from the top into the valley

Valley winddaytime

• Review over the key terms on page 565

• Define each of the key terms in your own words.

Diagrams page in your notebook• 1. draw the position of the sun and earth to

show the 4 seasons

• 2. draw the earth and sun to show how latitude effects sun angle/ intensity.

• 3. draw the layers of the atmosphere, include the ozone layer, jet stream and the 2 most abundant gasses.

• 4. draw a simple picture to show radiation, conduction and convection.

1. draw the position of the sun and earth to show the 4 seasons

2. draw the earth and sun to show how latitude effects sun angle/

intensity.

Nitrogen and oxygen

Jet stream

•3. draw the layers of the atmosphere, include the ozone layer, jet stream and the 2 most abundant gasses.

•4. draw a simple picture to show radiation, conduction and convection.

Jet stream

Nitrogen and oxygen

Review questions

• Page 565 Review the key terms and concepts for the chapter.

• Page 566 Answers only

• Questions 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 23, 24, 25, 26, 27, 31

• Page 568

• 1, 2, 4, 7,9

Greenhouse Effect Essay

• What is the greenhouse effect?

• Compare and contrast greenhouse gasses and ozone.

• What do they have in common?

• How are they different?

• What could happen if each of these is lost or each is increased?