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Definition
A) Earth supports life b/c of its climate
B) Water, nec. for life, exists in all 3 states of matter only on Earth to our knowledge
C) Venus has surface temp of 460 degrees C (860dF) b/c closer to sun and atmosphere is mostly carbon dioxide (CO2) w/ clouds of sulfuric acid; Thanks to radar on board USA's Magellan space probe which began orbiting Venus n 1990, we know: surface of Venus hot and dry; mntns, valleys, plains, and thousands of active volcanoes; few impact craters, meaning surface may be less than 1 billion years old; strange ringlike structures called "coronae" that range from about 95-360 miles in diameter; coronae believed to form when hot material from inside the planet rises to the surface
D) Mars has ave. surface temp of -55dC (-67dF) b/c further from sun and Mars has CO2, but atmosphere is very thin; also has clouds and ice at its north pole |
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| absorb certain wavelengths of longwave radiation thereby heating the gases; the heated greenhouse gases re-radiate heat back to Earth; our most abundant greenhouse gas is water vapor (usually 0-4% in atmosphere); carbon dioxide is our most important anthropogenic gas, BUT, there are natural sources of CO2 as well, other than just human activity; other greenhouse gases include methane, nitrous oxide, and ozone; we couldn't live w/out greenhouse exits, they keep our temps w/in ranges that support life, greenhouse effect NOT the same as global warming, but if you increase the amount of greenhouse gases in atmosphere, atmosphere will get warmer |
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| electromagnetic radiation/ electromagnetic wave |
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Definition
| an electromagnetic wave is an increasing disturbance consisting of oscillating (alternating) electric and magnetic fields that are perpendicular to each other; sun gives off electromagnetic radiation in different wavelengths |
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| distance from crest to crest of a wave |
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| electromagnetic radiation travels at the speed of light which in a vacuum is: 3.00 X 10^8m/s. speed is designated by the symbol c |
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| the number of wave crests that pass a designated point in 1 second. frequency designated by symbol "y" |
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| equation for speed of an electromagnetic wave |
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| "y" X "λ"=c... frequency times wavelength equals speed; if you keep speed constant (which it is since it's the speed of light in a vacuum), then if wavelength increases, frequency decreases and vice versa. KNOW THIS! |
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| a single "particle" or pulse of electromagnetic radiation, its the smallest independent amoint of energy transmitted by an electromagnetic wave of a given frequency |
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| (E) the amount of energy of a photon is given by the equation E = hy = hc/λ, where h= Planck's constant which is 6.63 X 10^-34 J-s (J-s= Joules-seconds). This says that high frequency, short wavelength photons have high energy and vice versa (low frequency, long wavelength photons have lower energy) |
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| 3 ways to transmit heat energy |
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Definition
| 1) conduction 2) convection 3) radiation |
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Definition
| molecular heat transfer in a solid |
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| molecular heat transfer in a liquid or gas |
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| heat transferred by electromagnetic waves- no medium necessary. This is how the sun transmits heat energy |
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| sun radiates mostly in this spectrum from .4µ to .7µ where µ = 10-6m. |
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| ultraviolet (UV), x-ray, and gamma ray spectrums have shorter wavelengths than the visible spectrum |
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Definition
| have shorter wavelengths than the visible spectrum. sometimes these wavelengths are called "shortwave radiation" but usually this term is referring only to the UV spectrum |
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| infrared (IR), microwave, and radio wave spectrums |
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Definition
| have longer wavelengths than visible spectrum. sometimes these wavelengths called "longwave radiation" but usually this term is referring only to the IR spectrum |
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Term
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Definition
the relationship between the maximum wavelength and temp of the radiating body is given by Wien's Law:. λmax = 2898/ Temperature (K)
where:
λmax = maximum wavelength
Wien's law says that the higher (hotter) the temp, the shorter the wavelength |
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Term
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Definition
E = σ ε T4 where:
E = Total energy (W/m2)
σ = Stefan-Boltzmann constant
(5.67 X 10-8 W/m2 K)
ε = emissivity (varies between 1 and 0)
T = temperature (K)
Says that total energy is MOSTLY dependent on temp and the higher the temp, the more energy is emitted |
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Definition
| a perfect absorber/emitter, meaning that whatever energy a blackbody absorbs, it emits. Example: Earth is considered a blackbody- right now... If Earth absorbs more energy than it emits, it warms and is no longer a blackbody; if Earth emits more energy than it absorbs, it cools and is no longer a blackbody |
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| energy emitted by a blackbody |
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| amount of energy or material that passes thru an area perpendicular to that area per unit time. Units of flux are W/m^2 |
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| temperature scales- 3 of them |
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Definition
1) Fahrenheit (used on surface weather maps in the USA)
2) Celsius (used on the upper air maps in the USA)
3) Kelvin (used in most meteorological calculations) |
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| vertical structure of atmosphere |
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Definition
| pressure decreases with height, but temp alternately decreases/increases w/ height |
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| gases selectively absorb radiation |
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Definition
| note the atmospheric window where longwave radiation from the Earth is emitted back to space: this means we cool by radiation! (also heat by radiation) |
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| planetary energy balance: Earth's surface temp depends on 3 factors |
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Definition
1) solar flux available at the distance of the Earth's orbit (closest to sun in Jan, furthest in July)
2) Earth's reflectivity (albedo)
3) amount of warming provided by the armosphere (greenhouse gases) |
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| What to know about the Earth's Energy Budget diagram |
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Definition
1) as long as the incoming heat energy equals the outgoing, the Earth remains a blackbody
2) 51% of the incoming solar radiation is absorbed by the surface. Absorption=heating!
3) 30% is reflected by to space. called "albedo" and reflected energy DOES NOT heat
4) latent (heat energy necessary to build and break molecular bonds in a state change) and sensible )heat energy you can feel) heat exchanges balance the uneven distribution of heat energy |
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| latitude is the most important control of temperature. due to latitude, incoming solar radiation is unevenly distributed |
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| Early, very simple computer models were used to estimate the amount of incoming versus outgoing radiation: |
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1) called Radiative Convective Models (RCMs)
2) one-dimensional models (vertical)
3) climate system is approximated by averaging the incoming and outgoing solar radiation over Earth's entire surface
4) RCMs can est, the magnitude of the greenhouse effect as a function of the concentration of greenhouse gases in the atmosphere |
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Term
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Definition
1) water vapor feedback very important! it is a greenhouse gas and when water changes state, latent heat energy is either released into the environment or absorbed
2)water vapor must be cooled to its dew point temperature before it condenses and releases the latent heat of condensation
3) if average temp of earth decreased, more water vapor would condense and would fall as rain or snow leaving less water vapor in the atmophere
4) less water in the atmosphere would mean furhter cooling since you are removing water vapor, a greenhouse gas, from the atmosphere |
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Term
| snow and ice feedback loops |
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Definition
1) cool the climate and the amount of snow and ice cover increase
2) this increases albedo which causes further cooling |
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Definition
1) earth's temp increases
2) corresponding increase in the IR flux from the earth going back into space
3) surface temps would start to decrease as more energy is lost into space
4) BUT- this loop can fail if there are large amounts of water vapor (or other gg's) in the atmosphere, meaning we would continue to heat despite the loss of IR radiation at the top of the atmosphere-- called the "runaway Greenhouse effect" |
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