Energy Transfer from Sun
Electromagnetic energy is a
type of energy that is
radiated by the sun in the
form of transverse waves
vibrating at right angles to
the direction of movement
Radiation occurs in different forms
identified by their wavelengths
The maximum intensity of insolation occurs
in the range of wavelengths of visible light
INSOLATION REACHING INTERFACE BETWEEN
SPACE / ATMOSPHERE IS DIFFERENT FROM THE
INSOLATION REACHING EARTH’S SURFACE
WHAT HAPPENS TO ELECTROMAGNETIC ENERGY (RADIATION) ONCE IT
REACHES EARTH?
Radiation is reflected – bounced back at the same angle they arrived
Radiation is scattered – reflected in various directions
Radiation is refracted - bent
Radiation is transmitted – pass through the material
Radiation is absorbed (taken in as heat energy)
Surface Properties
light vs. dark smooth vs. rough
SUN EMITS MAXIMUM INTENSITY IN THE
VISIBLE LIGHT RANGE
EARTH EMITS MAXIMUM INTENSITY IN THE
INFRARED RANGE
Once energy is absorbed within the EarthAtmosphere system
HEAT can be transported be 3 methods
Radiation
Conduction
Convection
Radiant
Energy
examples:
1. Sun
warms face
2. Apparent
heat of the
fire
CONDUCTION – MOLECULES TRANSFER
KINETIC ENERGY (KE) THROUGH
VIBRATIONS OR COLLISIONS
SOLIDS BEST
FOR
CONDUCTION
MOLECULES
CLOSE
TOGETHER
CONDUCTION – HEAT TRANSFERRED BY VIBRATIONS OF
ALUMINUM MOLECULES IN BAR - SOLIDS
CONVECTION – HEAT TRANSFERRED BY DENSITY
DIFFERENCES IN THE LIQUID – FLUIDS (LIQUIDS –
ATMOSPHERE)
CONVECTION OCCURS
IN THE ATMOSPHERE
CONDUCTION HEATS ONLY THE LOWEST ATMOSPHERE
TOUCHING EARTH’S SURFACE (UP TO ABOUT 6 FT.)
CONVECTION CAUSES AIR TO RISE DUE TO DENSITY
DIFFERENCES
EARTH ABSORBS SHORTWAVE RADIATION
EARTH EMITS LONGWAVE RADIATION –
TERRESRIAL INFRARED RADIATION
TROPOSPHERE IS MAINLY HEATED BY
RERADIATED TERRESTRIAL INFRARED
RADIATION FROM EARTH
“GREENHOUSE EFFECT”
GREENHOUSE GASES
CARBON
DIOXIDE
AND
METHANE
THE
BURNING
OF FOSSIL
FUELS
Life on Earth due to Greenhouse
Effect
Earth is the “Goldilocks Planet” – just right –
average temperature is 59° F (w/o GE our average
temperature would be -3° F)
Mars’ average temperature is -67° F (1/5 of our
atmosphere)
Venus’ average temperature due to GE is
855° F
Mercury’s temperature 333° F
RADIATION BALANCE
DYNAMIC EQUILIBRIUM
INPUT = OUTPUT
Is global warming changing the balance???????
Water heats up more slowly mainly
due to its high Specific Heat
(takes 5 x longer than land)
MODERATING EFFECT OF
LARGE BODIES OF WATER
By Charles Burrow s
50
90
45
80
40
70
35
60
30
50
25
40
20
30
15
20
10
5
10
0
0
9.62
7.87
7.37
4.93
3.28
2.57
1.16
MONTH
1.21
2.61
5.61
10.5
10.4
AVERAGE TEMPERATURE (F)
AVERAGE PRECIPITATION (inches)
CLIMOGRAPHS: 30-YEAR AVERAGES (1971 - 2000)
AKRON, OH
SAN DIEGO, CA
ABERDEEN, SD
CHARLESTON AP,SC
AKRON, OH
SAN DIEGO, CA
ABERDEEN, SD
CHARLESTON AP,SC
2 types of Heat Energy
Kinetic Energy – is energy in motion.
Temperature is the average KE of
molecules
Potential Energy – is energy in storage
aka latent heat or hidden energy. Cannot
be measured with a thermometer
Change in State (Phase Change)
Change in state is a change in potential
energy
Known as latent heat because it does not
cause a temperature change
During the phase change energy can be
absorbed or released but the energy is
hidden because it DOES NOT SHOW A
CHANGE IN TEMPERATURE
DURING CHANGE OF STATE, ENERGY IS CONVERTED TO POTENTIAL ENERGY
OR STORED HEAT – DOES NOT SHOW A CHANGE IN TEMPERATURE
Condensation and freezing – release energy
Evaporation and melting – require energy
¾ OF THE ENERGY ABSORBED BY
EARTH EVAPORATES WATER FROM
THE OCEANS
EVAPORATION
540 CALORIES/GRAM GAINED
The gram of water absorbed 540 calories of latent
heat as it changed to vapor (require addition of energy)
COOLING EFFECT
CONDENSATION
540 CALORIES/GRAM RELEASED
The gram of water released 540 calories of latent
heat as it changed to liquid (give off energy)
WARMING EFFECT