Chapter 3 and 7 Flashcards
Mid-term study
What kind of radiation is Earth absorbing from the sun?
mostly short wave; input as electromagnetic radiation
What kind of radiation does the Earth emit back?
mostly long wave
electromagnetic radiation equation
E= hv; where E= energy of quantum,
* h=Planck’s constant = 6.6x10–34 Js,
* υ = frequency s–1
How much radiation does the earth get from the sun as input?
Only 0.002% of total radiation emitted from sun forms input to earth
What is an ideal radiator?
shortwave length, high quality; solar radiation (black body)
What is the solar constant?
1370 W m–2
What does a short wavelength mean for wavelength?
shorter the wavelength the higher the frequency of ultraviolet radiation
What is a black body radiator dependent on?
on temperature of the object that is emitting; the hotter the temperature, the shorter the wavelength and higher the frequency
How does solar radiation change throughout the year?
radiation is not even throughout the year, varies seasonally: we are closest to the sun during the winter and further from the sun during the summer therefore this varies spatially and temporally
Thermal radiation relations
-stefan boltzmann’s law
-wavelength-frequency relationship
-wien’s displacement law
Stefan Boltzmann’s Law
describes the intensity of the thermal radiation emitted by matter in terms of that matter’s temperature
I=σT4
* where σ=5.67x10–8 Wm–2K–4, K = degrees Kelvin
Wavelength-frequency relationship
λ=c/υ
* where λ=wavelength, c=velocity of light, υ = frequency s–1)
Wien’s Displacement Law
states that the black-body radiation curve for different temperatures will peak at different wavelengths that are inversely proportional to the temperature.; emission
λm=w/T
* where λm=wavelength of maximum emission, w=Wien’s constants = 2.897 x 10–3 mK,
T=absolute temperature
Do earth and sun radiate at different wavelengths
yes; sun: short-wave (mostly visible); earth: long-wave (mostly infrared)
Without the atmosphere what is the long term balance net radiation?
net radiation = incoming radiation (mainly shortwave)
minus
outgoing radiation (mainly longwave)
= 0
Farenheit vs Celsius vs Kelvin
Water boils: 212F, 100C, 373K
Water freezes: 32F, 0C, 273K
Absolute O= -459F; -273C, 0K
Why does the sun and earth have different wavelengths?
The temperature of each is quite different; sun= 6000K; Earth: 59F~15C~288K
How does earth release energy?
through earthquakes, uplift (mountain formation) and formation of volcanoes
How do greenhouse gases work?
reradiation: The atmosphere allows most of the visible light from the Sun to pass through and reach Earth’s surface. As Earth’s surface is heated by sunlight, it radiates part of this energy back toward space as infrared radiation. This radiation, unlike visible light, tends to be absorbed by the greenhouse gases in the atmosphere, raising its temperature. The heated atmosphere in turn radiates infrared radiation back toward Earth’s surface.
atmosphere allows most solar
radiation to pass through it, but inhibits the passage
of terrestrial radiation
Radiation balance of the earth’s surface
Q= K+L
Does earth get more radiation from the atmosphere or the sun?
the atmosphere
radiation balance of the atmosphere
- QA=KA+LEA–LA–L
- KA (short wave from solar beam) = 17
- LEA (long wave from terrestrial radiation) = 91
- LA (long wave to space) = 57
- L (long wave back to earth) = 78
- Net radiation balance of –27
boundary of the atmosphere is both__
giving and receiving 100 units and its balance is 0
alternative energy exchange
-only considers radiant energy from sun and earth
How does annual and diurnal net radiation change in warm and cold?
- When negative there is cooling
- When positive there is warming
Conduction
the process of transferring energy, such as heat or electricity, from one object to another through direct contact
energy is transferred by direct contact
convection
-a heat transfer process that occurs due to the movement of a heated fluid; transfer of internal energy into or out of an object by the physical movement of a surrounding fluid
energy is transferred by the mass motion of molecules
Drives the global circulation
of the air and water, moves
energy from the surface back
to the atmosphere