solar radiation: the driving factor radiation (energy transmitted as waves, rays and particles)...
TRANSCRIPT
Solar Radiation: The driving factorSolar Radiation: The driving factor• • Radiation (energy transmitted as waves, rays and particles)Radiation (energy transmitted as waves, rays and particles)
released, absorbed &released, absorbed &
reflected by all thingsreflected by all things
• • travels as both a particle andtravels as both a particle and
a wavea wave
• • is affected by is affected by
-- gravity, magnetism, andgravity, magnetism, and
atmosphere composition,atmosphere composition,distance, angle of incidencedistance, angle of incidence
• • provides Earth with anprovides Earth with an
external source of energyexternal source of energy
The sun produces most of its electromagnetic
energy in intermediate wavelengths / frequencies.
A. TrueB. False
Sources of radiation
• Sun and other stars are dominant source
- Sun is closest so it has a greater influence
• Earth emits some energy as well
- Solar radiation is absorbed by Earth andtransformed into longwave radiation
• Many other planets emit radiation as well
- e.g., Jupiter and Saturn- source is from the planet itself
not all is absorbed and re-emitted like Earth
The Sun• 93 million miles from Earth• It rotates once every 600 hrs (25 days)
• Has hot spots and "cool" spots- sunspots are relatively "cool"
• Produces electro-magnetic radiativeenergy
- concentrated inUV, Visible & IR spectral classes
Sunspots - cyclical magnetic “storms” that occur in 11 year cycles are lower in temperature, but increase solar output.
Sunspots - cyclical magnetic “storms” that occur in 11 year cycles are lower in temperature, but increase solar output.
Solar Max = lots of sunspots and increased energy output Solar Min = few to no sunspots and decreased energy output
Solar Max = lots of sunspots and increased energy output Solar Min = few to no sunspots and decreased energy output
Frequency (mHz) refers to vibration of particlesWavelength () = distance between wave crests
Electromagnetic SpectrumElectromagnetic Spectrum
Long Short
(
Position affects radiation• Far away=less radiation• Titled toward= more radiation• Far away=less radiation; Closer=more radiation• Titled away=less radiation; Tilted toward = more
The northern hemisphere experiences winter because the Earth is farther away from the Sun than it is during the summer months.
A. True
B. False
Summer Solstice Winter Solstice
• Sun's energy at 90°
at Tropic of Cancer
• Sun overhead at noon
• Sun's energy at 90°
at Tropic of Capricorn
• Sun overhead at noon
> ~June 21 ~December 21
Eccentricity100 kyr cycle
aphelion
Earth’s orbit
Obliquity41 kyr cycle
Perpendicular to the eclipticPerpendicular to the ecliptic
Axis 20 kyr agoAxis 20 kyr ago
Axis at presentAxis at present
Axis at 20 kyr in futureAxis at 20 kyr in future
Conditions now
Conditions 11 kyr ago
Precession of Equinox 22 kyr cycle
sun
sun
Earth at aphelion
Earth at perihelion
Path of Earth’s orbit around the sun
QuickTime™ and aSorenson Video 3 decompressorare needed to see this picture.
Precession 22 kyr cycle
Milankovitch cycles- pacemaker to the ice agesMilankovitch cycles- pacemaker to the ice ages
fromO18 ice and deep sea sediment cores
*
The atmosphere acts as a mirror, prism and a trap
• Scatters some of the radiation
- why the sky is blue
• Reflects some of the radiation
- clouds, snow, water etc.
• Absorbs some of the radiation
- ground, ozone, dust, etc.
Ozone & dust
Dust & clouds
Clouds & gases
mirror
prism
trap
Distribution of Radiation
• energy balance diagram
Albedo
・ A measure of the amount of reflected radiation
・ Some things reflect radiation better than others
- "dry" or "cold" Snow & Ice = high albedo- water = moderate for visible, low for infrared- plants= moderate for visible
・ Land absorbs and releases radiative energyquicker than water
Albedo = ________________incident radiationreflected radiation
Albedo of land surfaces on EarthAlbedo of land surfaces on Earth
Data collected by NASA’s MODIS satellite, April 2002Data collected by NASA’s MODIS satellite, April 2002
Warm colors are higher; cool are lower; white no data availableWarm colors are higher; cool are lower; white no data available
IR output from Earth
K
Effects of cloud type on radiation budget
• different types of interference havedifferent effects on Earth's energy budget