ns2 3.1 our atmosphere

CHAPTER 1

OUR ATMOSPHERE

Our atmosphere has many layers up to

about 1,000 miles above the Earth’s

surface.

TROPOSPHERE (UP to 11 MILES)

STRATOSPHERE (11 to 30 MILES)

MESOSPHERE (30 to 50 MILES)

THERMOSPHERE (50 to 3721 MILES)

EXOSPHERE (372 to 18,000 MILES)

The gaseous envelope surrounding

the Earth; the air

Atmosphere

Our atmosphere is a mixture

of different gases.

oxygen

nitrogen

argon 1%

21%

78%

Scattered within the atmosphere is about

1 percent water vapor, called humidity.

Amount of moisture in the air

Humidity

Equatorial

Polar

Polar

The amount of water vapor is greater in

equatorial regions than in polar regions.

Water is nearly incompressible. A cubic

foot of surface water weighs about the

same as a cubic foot taken from the

Marianas Trench.

Not compressible

Incompressible

However, with air,

a cubic foot taken

from a lower

altitude weighs

more than a cubic

foot taken at a

higher altitude,

therefore it is

compressible.

To press together; force into less

space; to condense

Compressible

Mesosphere

Stratosphere

Troposphere

50 miles

30 miles

11 miles

3.5 miles

Virtually all of the

Earth’s weather

(tempestuous air

ocean) occurs

within the first

3.5 miles of our

atmosphere.

Tumultuous; turbulent

Tempestuous

About 99% of the

atmospheric

gases lie below

20 miles.

20 MILES

Troposphere

Beyond 45 miles, only

helium and hydrogen

exist in minute amounts.

322 MILES

11 MILES

20 MILES

20 MILES

The atmosphere consists of five

principal layers.

THE TROPOSPHERE

THE STRATOSPHERE

THE MESOSPHERE

THE THERMOSPHERE

THE EXOSPHERE

39,600 MILES

322 MILES

20 MILES

20 MILES

20 MILESTHE

EARTH

18,000

372

50

30

11 milesChemosphere

(Ozone)

Tropopause

18,000

372

50

30

11 milesChemosphere

(Ozone)

The tropopause lies between the

troposphere and the stratosphere.

18,000

372

50

30

11 miles

Tropopause

The chemosphere (ozone layer) lies

mainly between the stratosphere and

mesosphere.

18,000

372

50

30

11 milesChemosphere

(Ozone)

Tropopause

500

Ionosphere

The ionosphere is the whole area

encompassing the mesosphere

and the thermosphere.

What element or gas makes up the

majority of the Earth’s atmosphere?

a. Nitrogen

b. Oxygen

c. Argon

d. Carbon dioxide

The troposphere extends to a height

of about 11 miles above the equator,

some 7.5 miles in the temperate zones,

and only about 5 miles above the poles.

THE

EARTH 11 MILES

THE TROPOSPHERE

The lowest layer of the atmosphere,

within which there is a steady drop

in temperature with increasing

altitude and within which nearly all

cloud formations occur and weather

conditions manifest themselves

Troposphere

Nearly all clouds are in the troposphere,

so it is here that weather occurs. Air

heated by the Earth rises, in a process

called convection.

The transport of atmospheric properties

upward

Convection

In the troposphere,

the air automatically

changes about 5½°

for each 1,000 feet

traveled vertically.

This is called

adiabatic warming

or cooling.

Troposphere

56 °F (Sea level)

85 °F

The constant rate change in temperature

with altitude

Adiabatic

Swift movement of cold air masses

about the vast Antarctic continent is

a major factor in determining the

world’s weather.

New

Zealand South

America

Antarctica

The tropopause is a transitional zone

between the troposphere and the near

void of the stratosphere. It starts just

above the troposphere (5 - 11 miles) and

is divided into three overlapping areas:

• Tropical • Extra-tropical • Arctic

50

30

11 miles

The boundary, or transitional layer,

between the troposphere and the

stratosphere

Tropopause

Located in the area between 20,000 and

40,000 feet is the jet stream. It is most

prominent above the extra tropical and

Arctic tropopause overlap.

Jet Stream

Strong, generally westerly winds

concentrated in a relatively narrow

and shallow stream in the upper

troposphere of the Earth

Jet Stream

The jet stream was discovered in WW II,

when B-29 bombers flying about 4 miles

high, found great assistance from

westerly winds of up to 300 mph.

It has been found that jet streams are

the strongest over Japan and the New

England states.

Summer Jet Stream

Three major jet streams move over the

North American continent in winter, one

of which nearly blankets the United States.

The jet streams move with cooler air

masses near the Earth’s surface. In

winter the jet streams are over the

temperate zones, while in summer, the

jet streams move much farther north,

out of most of the main commercial

lanes.

In which layer of the atmosphere is the

“jet stream” located?

a. Stratosphere

b. Ionosphere

c. Tropopause

d. Exosphere

The stratosphere lies just above the

tropopause and extends to an altitude

of about 30 miles. There is almost no

weather here due to the thin air and

few clouds.

THE

EARTH

30 MILES

THE STRATOSPHERE

The region of the upper atmosphere

extending upward from the

tropopause to about 30 miles (50 km)

above the Earth, characterized by little

vertical change in temperature (a

fairly constant -40 to -50 °F)

Stratosphere

Modern commercial airlines seek to fly

in the stratosphere when not using the

jet stream because there is so much

less air resistance. This makes for

better fuel mileage, little turbulence,

and flight at top speeds.

Commercial airline pilots favor flying in

the ________ because there is less air

resistance and no turbulence.

a. tropopause

b. stratosphere

c. ionosphere

d. exosphere

18,000

372

50

30

11 miles

500

The ionosphere is an area of electrically

charged ions lying above the

stratosphere. It begins 30 - 40 miles up

and extends to about 500 miles.

The region of the Earth’s atmosphere

between the stratosphere and the

exosphere, consisting of several

ionized layers and extending from

about 50 - 250 mi. (80 - 400 km)

above the surface of the Earth

Ionosphere

An electrically charged atom or group

of atoms formed by the loss or gain

of one or more electrons

Ion

Disturbances from the Sun can cause

changes in the ionosphere’s form.

These magnetic and electrical storms

cause the Northern Lights.

The ionosphere

will reflect radio

waves of certain

frequencies.

By determining the

best frequencies

and times of day to

transmit messages,

communications are

greatly enhanced.

THE

EARTH

30 MILESTHE MESOSPHERE

11 MILES

The lowest level of the ionosphere, the

mesosphere, extends from 30 - 50 miles

above the Earth. Temperatures range

from a high of 32 °F to a low of minus

100 °F.

The region between the ionosphere

and the exosphere, extending from

about 30 - 50 mi. above the surface

of the Earth

Mesosphere

THE

EARTH

322 MILES

THE THERMOSPHERE

The thermosphere is the highest layer

of the ionosphere. The principal radio

reflecting layers are here. Temperatures

in the thermosphere may reach 1,700 °F

at 300 miles up.

The region of the upper atmosphere

in which temperature increases

continuously with altitude,

encompassing essentially all of the

atmosphere above the mesosphere

Thermosphere

Starting below and extending into the

ionosphere is the chemosphere (ozone

layer). It begins at about 15 miles up

and shields the Earth from the harmful

ultraviolet rays of the Sun.

18,000

372

50

30

11 miles

The region of the atmosphere most

characterized by chemical,

especially photochemical activity,

starting in the stratosphere and

including the mesosphere and

perhaps part of the thermosphere

Chemosphere

The layer of the upper atmosphere

where most atmospheric ozone is

concentrated, from about 8 - 30 mi.

(12 - 48 km) above the Earth, with

the maximum ozone concentration

occurring at an altitude of about

12 mi. (19 km.)

Ozone Layer

The ozone layer is being depleted by

fluorocarbons used as propellants for

aerosol cans and refrigerants used for

air conditioning systems.

Any of a class of compounds

produced by substituting fluorine

for hydrogen in a hydrocarbon, and

characterized by great chemical

stability: used chiefly as a lubricant,

refrigerant, fire extinguishing agent,

and in industrial and other

applications in which chemical,

electrical, flame, and heat resistance

is essential; banned as an aerosol

propellant in the U.S. because of

concern about ozone layer depletion

Fluorocarbons

A compressed inert gas that serves

to dispense the contents of an

aerosol container when the pressure

is released

Propellant

The ozone layer shields the Earth from

the harmful ultraviolet rays of the Sun.

Another name for this layer is

the _________.

a. chemosphere

b. thermosphere

c. mesosphere

d. exosphere

The exosphere

begins about 500

miles above the

Earth’s surface

and continues

out about 18,000

miles. Only light

hydrogen and

helium atoms

exist because of

intense cosmic radiation.

Temperatures may range from 4,500 °F

to near absolute zero.

18,000

The highest region of the atmosphere,

where the air density is so low that a

fast-moving air molecule is more than

50 percent likely to escape from the

atmosphere instead of hitting other

molecules

Exosphere

Located within the exosphere are intense

radiation areas called the Van Allen

Radiation Belts.

Van Allen Radiation Belts

Either of two regions of high-energy-

charged particles surrounding the

Earth

The Inner region is centered at an

altitude of 2,000 mi. (3,200 km) and

the outer region at an altitude

between 9,000 and 12,000 mi.

(14,500 and 19,000 km).

Van Allen Radiation Belt

The inner belt is located about 400 -

3,400 miles above the Earth. It contains

high-energy protons.


Inner

Belt


Outer

Belt

The outer belt is located 8,000 - 40,000

miles above the Earth. It contains high-

energy electrons.

Manned space

missions are

intentionally flown

well below the

lower limits of the

Van Allen Belts,

and satellites

operating in these

regions must be

shielded against

the radiation

encountered there.

What layer of our atmosphere has

intense cosmic radiation?

a. Tropopause

b. Stratosphere

c. Ionosphere

d. Exosphere

The weight of the atmosphere varies

with the amount of water vapor present,

the temperature, and the height above

the Earth’s surface. A barometer

measures variations in atmospheric

pressure.

Generally employed

for use at sea, the

mercurial type

barometer consists

of an accurately

calibrated glass tube

filled with mercury.

It is used at shore

activities to check

aneroid barometers

for accuracy.

Mercurial Barometer

Containing the metal mercury

Mercurial

Divided or marked with gradations,

graduations, or other indexes of

degree, quantity, etc., as on a

thermometer, measuring cup, or

the like

Calibrated

Using no fluid

Aneroid

Vacuum Chamber

Lever

Spindle

PointerAneroid Barometer

The aneroid, or

dry barometer,

contains a small

metallic cell that

atmospheric

pressure

increases and

expands when

pressure

decreases

moving a needle

that points to a

graduated scale.

Marked with divisions or units of

measurement

Graduated

Barometers can be graduated in either

inches of mercury or millibars. Millibars

are normally used on weather charts.

The metric unit of measurement for

air pressure

A centimeter-gram-second unit of

pressure equal to one thousandth

of a bar or 1000 dynes per square

centimeter, used to measure air

pressure

Millibar

The average atmospheric pressure at

the Earth’s surface is 29.92 inches, or

1,013.2 millibars.

An air mass is a large body of air with

the same temperature and humidity. It

generally takes on the characteristics of

the surface over which it forms but has

different characteristics.

A body of air covering a relatively

wide area, exhibiting approximately

uniform properties through any

horizontal section

Air Mass

It takes more heat to warm water

temperatures than soil temperatures.

In seawater, heat is absorbed to depths

in excess of 80 feet.

Only a few inches of topsoil will

absorb radiation. This means oceans

are slower to warm up and cool down

than landmasses.

In winter, the United States is swept

by continental air masses from the

cold Arctic.

Winter

Air Masses

In summer, we are swept by warm,

moist maritime air masses.

Summer

Air Masses

When warm and cold air masses touch,

the boundary between them is called a

front.

An interface or zone of transition

between two dissimilar air

masses

Front

A warm front is formed when a warm air

mass moves over a cold air mass; when

the reverse occurs, it is called a cold

front.

Cold Front Warm Front

A transition zone between a mass

of warm air and the colder air it is

replacing

Warm Front

A transition zone between a mass

of cold air and the warmer air it is

replacing

Cold Front

When neither

mass advances

on the other, a

stationary front is

said to exist.

Cold

Front

Stationary

Front

Warm

Front

A front between warm and cold air

masses that is moving very slowly,

or not at all

When a warm or cold front stops

moving, it becomes a stationary

front.

Stationary Front

Violent frontal weather systems can

be predicted from a chart showing

atmospheric pressures.

Weather charts usually illustrate

barometric pressures as millibar reading

points. The lines on the above map,

drawn through points of equal pressure,

are called isobars, which never join or

cross.

A line drawn on a weather map

that connects points at which

the barometric pressure is the

same

Isobars

Isobars give a rough indication of the

amount of wind in an area. The closer

the bars, the stronger the wind in that

area.

The weight of the atmosphere varies

from place to place depending on

which of the following?

a. Wind, temperature, pressure

b. Temperature, height, wind

c. Water vapor, temperature,

height

d. Water vapor, pressure, wind

Weather is the condition of the

atmosphere, expressed in terms of its

heat, pressure, wind, and moisture.

It is heat, and the transfer of heat, that

causes the weather. Without it there

would be no winds, varying air

pressures, storms, rain, or snow. All

weather changes are caused by

temperature changes in different parts

of the atmosphere.

Fundamental natural laws determine

weather changes:

• Warm air is lighter

in weight and can

hold more water

vapor than cold

air.

• Cold air is heavier

and has a tendency

to flow toward the

rising warm air.

Fundamental natural laws determine

weather changes:

• As air moves, wind

is created. This is

beginning of the

complex forces that

cause the changing

weather.

The Sun is our principal source of

energy:

• It bombards the Earth with 126 trillion

horsepower each second.

• Its energy waves, or radiation, travel

at 186,300 miles per second (speed

of light).

• About 43% of the radiation reaching

our planet is changed into heat.

Solar energy is referred to as insolation.

Solar radiation received at the

Earth’s surface

Insolation(INcoming SOLar radiATION)

Clouds and other atmospheric influences

absorb some of the incoming radiation,

but they reflect much of it.

• Clouds reflect back 75% of sunlight.

• Earth’s average cloudiness is 52%.

• About 36% of the total insolation never

reaches Earth.

Dense forests absorb 95% of insolation.

Water reflects 60 - 96% of insolation,

depending on the angle the light hits the

surface.

In effect, the Earth’s

cloud cover acts like

the glass of a

greenhouse. It lets

short solar rays

pass through; the

Earth absorbs the

ones that get

through, then

re-radiates long

heat rays.

Long heat waves

cannot all get

through the

atmosphere

because they are

absorbed by water

vapor, so they

stay within the

“greenhouse” in a

continual cycle.

Atmosphere

Earth

Heat

Without atmosphere, the Earth would be

like the Moon with boiling temperatures

during the day and sub-freezing

temperatures during the night.

Even though clouds and other

atmospheric influences absorb some of

the incoming radiation from the Sun,

____ percent of the sunlight is reflected

back into space.

a. 70

b. 75

c. 80

d. 85

The Navy and most

civilians in America

use thermometers

with a Fahrenheit

(F) scale.

Steam Point

Ice Point 32°F

212°F

Fahrenheit

Noting, pertaining to, or measured

according to a temperature scale in

which 32° represents the freezing

point and 212° the boiling point

Fahrenheit

Temperatures in

meteorology and

most other sciences,

however, are usually

expressed according

to the Celsius (C)

scale.

Boiling

Point

Freezing

Point

Celsius

0°C

100°C

Pertaining to or noting a temperature

scale in which 0° represents the

freezing point and 100° the boiling

point of water

Celsius

The Celsius scale is a metric system, which one

day is supposed to be the principal measurement

system used in the United States as it already is in

most of the rest of the world.

There are 5 °C temperature for every

9 °F.

Formula: C = 5/9 (F - 32)

Since 32 °F is equivalent to 0 °C, to

change a Fahrenheit reading to

Celsius, you subtract 32° and then

multiply the remainder by 5/9.

What is the temperature in Celsius

if it is 59 °F?

What is the temperature in Celsius

if it is 59 °F?

- 32 °

59 °

27 °

27 °

1

5

9= 15 °CX

Conversion Formula

This process is reversed to convert

Fahrenheit to Celsius.

Formula: F = 9/5 C + 32°

What is the temperature in Fahrenheit

if it is 15 °C?

+ 32 °

27 °

59 °F

15 °

1

9

5= 27 °X

What is the temperature in Fahrenheit

if it is 15 °C?

If you compare these

thermometers, you will

note that the top of the

column of alcohol is in

the shape of a curve

called a meniscus. The

accurate reading for an

alcohol thermometer is

at the bottom of this

curve; for mercury it is

at the top.

Alcohol in Glass

Mercury in Glass

A crescent or a crescent-shaped

body

The convex or concave upper

surface of a column of liquid, the

curvature of which is caused by

surface tension

Meniscus

Heat causes evaporation of millions of

tons of water daily.

A process called transpiration causes

additional huge amounts of water to enter

the air from the green leaves of plants.

The passage of water through a plant

from the roots through the vascular

system to the atmosphere

Transpiration

As warm, moist air rises, it expands and

cools, eventually reaching its saturation

level (100% relative humidity) and causes

the vapor to condense into a liquid. Water

droplets form in the clouds, and

precipitation occurs.

Falling products of condensation in

the atmosphere, as rain, snow, or

hail

Precipitation

This hydrologic cycle of evaporation,

condensation, and precipitation is

continually in process.

Precipitation

on Land

Evaporation

from Land Evaporation

from Ocean

Precipitation

on Ocean

Moisture

over Land

The natural sequence through which

water passes into the atmosphere as

water vapor, precipitates to Earth in

liquid or solid form, and ultimately

returns to the atmosphere through

evaporation

Hydrologic Cycle

Since warm air can hold more moisture than

cold air, relative humidity goes up when air

with a given amount of water vapor cools,

and drops when that air is heated.

The amount of water vapor in the air,

expressed as a percentage of the

maximum amount that the air can

hold at the given temperature

Relative Humidity

When air is cooled to its dew point temperature,

small water droplets condense on objects and

dew is formed.

The temperature to which air must

be cooled, at a given pressure and

water vapor content for it to reach

saturation

The temperature at which dew

begins to form

Dew Point

Relative humidity

is measured using

a psychrometer.

Psychrometer

An instrument for determining the

atmospheric humidity by the reading

of two thermometers, the bulb of one

being kept moist and ventilated

Psychrometer

Sling psychrometers are often used aboard

ship to speed up the process of getting

accurate wet and dry-bulb readings.

Sling Psychrometer

A psychrometer so designed that

the wet-bulb thermometer can be

ventilated, to expedite evaporation,

by whirling in the air

Sling Psychrometer

The process by which millions of tons

of water from the green leaves of plants

enter into the atmosphere is called

__________.

a. evaporation

b. transportation

c. perspiration

d. transpiration

Q.1. TRUE or FALSE. The harsh

Russian winter weather was a

factor that helped defeat Hitler

in World War II.

A.1. TRUE

Q.1. TRUE or FALSE. The harsh

Russian winter weather was a

factor that helped defeat Hitler

in World War II.

Q.2. Who invented the

thermometer?

A.2. Galileo

Q.2. Who invented the

thermometer?

Q.3. Who developed a system for

organizing weather

observations?

A.3. Leverrier

Q.3. Who developed a system for

organizing weather

observations?

Q.4. Who developed air-mass and

polar-front theories of weather?

A.4. Bjerknes

Q.4. Who developed air-mass and

polar-front theories of weather?

Q.5. What does synoptic

meteorology mean?

A.5. A general view of the weather

Q.5. What does synoptic

meteorology mean?

Q.6. How do meteorologists use

satellites?

A.6. As observational tools

Q.6. How do meteorologists use

satellites?

Q.7. What name is given to the

science of weather?

A.7. Meteorology

Q.7. What name is given to the

science of weather?

Q.8. What was the first

meteorological instrument to

be developed?

A.8. A crude hygrometer

Q.8. What was the first

meteorological instrument to

be developed?

Q.9. What is the troposphere?

A.9. An ocean of air immediately

above the Earth’s surface

Q.9. What is the troposphere?

Q.10. What is the tropopause?

A.10. The transitional zone between

the troposphere and the near

void of the stratosphere

Q.10. What is the tropopause?

Q.11. What is adiabatic warming and

cooling?

A.11. The consistent temperature

change due to change in

altitude

Q.11. What is adiabatic warming and

cooling?

Q.12. What is a jet stream?

A.12. A current of air that moves

swiftly from west to east

around the Earth

Q.12. What is a jet stream?

Q.13. In the Navy, what two types of

barometers are used?

A.13. Mercurial and aneroid

Q.13. In the Navy, what two types of

barometers are used?

Q.14. What is the topmost layer of

the atmosphere?

A.14. Exosphere

Q.14. What is the topmost layer of

the atmosphere?

Q.15. What is the lowest level of the

ionosphere?

A.15. Mesosphere

Q.15. What is the lowest level of the

ionosphere?

Q.16. What is the highest level of the

ionosphere?

A.16. Thermosphere

Q.16. What is the highest level of the

ionosphere?

Q.17. What is a front?

A.17. When warm and cold air

masses touch, the boundary

between them is a front.

Q.17. What is a front?

Q.18. What is an air mass?

A.18. A large body of air with the

same temperature, humidity,

and pressure

Q.18. What is an air mass?

Q.19. Which layer shields the Earth

from the Sun's harmful

ultraviolet rays?

A.19. The chemosphere or ozone

layer

Q.19. Which layer shields the Earth

from the Sun's harmful

ultraviolet rays?

ns2 3.1 our atmosphere

Education