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Chapter 16
Section 1 pg. 542
Energy In Earth’s Atmosphere
Energy from the Sun
Electromagnetic waves- form of energy that can
move
through the vacuum of space.
All energy comes from the sun
Radiation – direct transfer of energy by
Electromagnetic waves
Visible light= all the colors in a rainbow
Colors each have different wavelength( red =
longest, Blue = shortest)
Non Visible Radiation=
Infrared (from of electromagnetic) radiation has
longer wave lengths than red, not visible but is heat
Ultraviolet radiation= invisible energy with shorter
than violet wavelengths , causes Sunburn, eye damage, skin
cancer
Energy in the Atmosphere
Some sunlight is absorbed or reflected by atmosphere
before it can reach the surface. The rest passes through
the atmosphere to surface.
Ozone absorbs ultraviolet radiation
H20 and CO2 absorb some infared radiation
Clouds, dust, and other gases absorb energy
Scattering- reflection of light in all directions caused by
dust and gases in atmosphere.
Energy at Earth’s Surface
Half of energy is absorbed by the land and water and
changed to heat.
When Earth’s surface is heated it radiates most of the
energy back into the atmosphere as infrared radiation.
Greenhouse Effect- process which gases hold heat in the air
(Blanket holding heat in)
Natural process that keeps Earth temp. comfortable and
balanced
Section 2
Heat Transfer
Thermal Energy and Temperature
All objects are made of tiny particles that are constantly
moving (the faster they move the more energy they have)
Temperature_- average amount of energy of motion of each
particle of a substance
- measure of how hot or cold a substance is
Thermal energy- total energy of Motion in the particles of a
substance
Ex. Tea in the cup and the teapot
Measuring temperature- important factors affecting the
weather
Air temperature= usually measured with a thermometer
Thermometer- thin glass tube with a bulb on one end that
contains a liquid(mercury) or colored alcohol.
- liquid can expand due to temperature
Temperature scales
- measured in degrees
- Celsius 0 to 100 degrees
- Fahrenheit 32 to 212 degrees
How Heat is Transferred
Heat-transfer of thermal energy (hot object to
cooler one)
3 ways of transfer
Radiation- direct transfer of energy by
waves
EX. Feel the heat from the sun
electromagnetic
Conduction- the direct transfer of heat from one substance
to another that is touching
EX. Hot feet from walking on hot sand
Convection- transfer of heat by the movement of fluid
EX. Boiling water
See fiqure on pg 551
Heating the Troposphere
All three ways work together to heat the troposphere
Convection currents- upward movement of warm air and
downward movement of cool air
- move heat throughout the troposphere
Section 3 Winds
Pg 552
What is Wind
Horizontal movement of air from an area of high pressure of area
of low pressure
Winds are caused by differences in air pressure
Differences of air pressure is caused by unequal heating of Earth’s
atmosphere.
Warm air rises
Measuring Winds- direction measured by wind vane
- speed measured by anemometer ( 3 or 4 cup attached to
axle)
Wind-Chill Factor-increased cooling a wind can cause
Local Wind
Winds that blow over short distances
Local winds are caused by the unequal heating of Earth’s surface
within a small area.
Sea Breeze
Global Winds
Winds that blow steadily from specific direction over long
distances.
Created by unequal heating
Occur over large area
Global convection current
Warm air rises at equator and cool air sinks at poles
Air pressure is lower at equator& grater at poles
Causes wind to blow from poles to equator near the
surface. Higher up it goes the other way.
Coriolis Effect – way the Earth’s rotation makes winds curve
Global wind in N hemisphere turn right and S turn left
Global Wind Belts
Dolrums- regions near the equator with little to no wind
Horse latitudes- 30 degrees north and south of the equator where
little to no wind blows (calm areas of falling air)
Trade winds- blow from the horse latitudes toward the equator
(steady easterly winds) named due to sailors using them to trade
Prevailing Westerlies- blow away from the horse latitudes between
30 degrees and 60 degrees North and South
Winds that blow toward the poles turned east by Coriolis effect
Important part of weather in US
Polar Easterlies- blow cold air away from the poles
Coriolis effect shifts wind to the west
Mixing of warm and cold air along polar front has major effect on
weather in US
Jet Streams- 10 kilometers above surface
High speed winds
Very wide not very deep
Blow from west to east at about 200 to 400 kilometers per hour
Wander n and S in a wavy path.
Section 4
Water in the Atmosphere
Pg 560
Water cycle- movement of water between the atmosphere and Earth’s surface
See pg 561
Evaporation- water molecules in liquid water escape into the air as water vapor.
HumidityMeasure of the amount of water vapor in the air
Warm air can hold more than cold air
Relative Humidity- percentage of water vapor that is actually in the air
compared to maximum the sir can hold at a certain temp.
Psychrometer – instrument that measures relative humidity
Has a wet bulb thermometer and dry bulb thermometer
How Clouds Form
When water vapor in air condenses to form liquid water or ice crystals
Condensation – water vapor becomes a liquid
Ex. – cold glass of lemonade is wet on the outside of glass
Role of cooling
Cold air holds less water vapor than warm air
When air cools water vapor decreases to form droplets of water
Dew point- temperature when condensation begins
Role of particles
Particles are dust, salt, smoke
This gives the water something to condense on
Dew is liquid water condensing from the air onto a cooler like grass
Frost is ice that has been deposited on a surface that is below freezing
Types of Clouds
3 types based on shape and altitude
Cirrusfeathery wispy
form at high levels (above 6 Km)
made of ice crystals
Cirrocumulus- look like rows of cotton balls
- indicate a storm is coming
Cumulus
Fluffy rounded piles of cotton
Form less than 2 Km above the ground
Grow in size and height till reach 18 Km
Ones not very tall = fair weather
Tall ones with flat tops= Thunderstorms (Cumulonimbus) Nimbus
means rain
Stratus
Flat layers
Strato = spreadout
Cover most of the sky
Gray color
When thicken produce drizzle , rain, or snow
Altocumulus and Altostratus
Middle level clouds
Between 2 and 6 Km above surface
In between cumulus and cirrus
Fog
Clouds that form at or near the ground
Forms when ground cools at night after hot humid day
Section 5
Precipitation
form of water that falls from clouds and reaches Earth’s surface
For precipitation to fall needs to be heavy enough to fall through the air.
Types of Precipitation
Rain = most common
.5 mm in diameter
smaller is called mist
Sleet= raindrops that fall when air is less than 0 degrees C
Smaller than 5 mm is diameter
Freezing Rain=when raindrops freeze when they touch a cold surface
Snow= water vapor in a cloud is converted directly into ice crystals
Hail= round pellets ice of larger than 5 mm in diameter
Forms inside a cold region of a cloud
Small pieces bounce in the clouds till they get to big and fall
Modify precipitation
Droughts- long periods of unusually low precipitation
Cloud seeding- tiny crystals of silver are iodine and dry ice are
sprinkled into the air from a plane so that the water vapor in air
will condense on it causing rain
Not very effective
Measuring Precipitation
Snowfall measurement- measured with a ruler or yard stick
- or by melting snow and find the depth
- 10 cm of snow =1 cm of rain
Rain measurements
Rain gauge- open ended tube that collects rainfall