6.1-6.3
暂无描述。系统推荐的高质量记忆内容，适合每天坚持背诵学习。
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what drives weather and climate?
almost 100% energy flows from sun - a little from molten core and tidal energy
~__% of sun’s rays are reflected back from earth’s surface
30%
albedo
fraction of sun’s energy reflected or scattered back into space - reflected from earth’s surface or atmosphere - contributes to E’s energy balance
~__ % of absorbed energy flows through the hydrologic cycle
50%
how is energy absorbed/released in the hydrologic cycle?
• evaporation = water takes up energy • precipitation from freshwater = water releases energy
where are the effects of climate change the worst?
polar regions
shorter wavelength =
higher temp
steady balance of earth’s energy
constant flow of energy in/out = constant avg temps - amnt of energy from sun –> earth = amnt of energy from earth –> space - keeps temperatures cooler
earth emits ___
blackbody radiation
what wavelength(s) of light does earth radiate?
infrared light region = > 700 nm (earth = ~10,000 nm)
what wavelength(s) of light does the sun radiate?
visible light region = (400-700 nm)
energy flux from sun (S0) =
• amount of light/area • = 1370 Wm^-2
Stefan Boltzmann law
rate at which blackbody radiates energy 4th power of absolute temp
Stefan boltzmann equation
S = kT4 - k = 5.67 x 10^-8 Wm^-2 x K^4
what is earth’s surface temp?
288 °K = 15 °C
greenhouse effect
atmosphere traps heat from radiating back = raises surface temp - makes planet habitable (prevents world from freezing) - enhanced too much, CO2 and ghgs increase trapping
Total energy from sun =
15.1 x 108 TWh (terawatt hours)
total energy reflected by atmosphere =
3.9 x 108 TWh
photosynthesis energy =
0.024 x 108 TWh
infrared radiation
earth re-radiates energy as infrared radiation - beyond visible light spectrum - long wavelength radiation = carrying heat
blackbody radiation
radiation emitted from source that doesn’t generate any energy of its own (ex: earth doesn’t generate it’s own energy; receives from sun) - amnt/type of energy emitted by objects at a certain temp
infrared light wavelengths
> 700 nm
visible light wavelengths
400-700 nm
UV light wavelengths
< 400 nm