solar energy + energy budget Flashcards
what does the sun emit
Sun = 6000 degrees Celsius – emits high-energy shortwave radiation
- Solar radiation (shortwave) = 200-4000nm (0.2-0.4 um)
what does earth emit
Earth = 15 degrees Celsius – emits low-energy longwave radiation
- Earth radiation (longwave) = 5000-25000nm (5.0-25.0 um)
radiation inputs vs outputs?
input=shortwave
Output = longwave
what are the major chemical components of the atmosphere
Nitrogen – 78.1 limiting
Oxygen – 20.9
Argon – 0.93
Carbon dioxide – 0.04
what do gases in the air absorb?
Gases in the air absorb wavelengths:
CO2 – longwave lengths
H20 – shortwave lengths
what are aerosols
small particles suspended in atmosphere
describe aerosols
Natural (volcanic eruptions, dust, sea salt) or Anthropogenic
(pollution)
- Nuclei for water condensation
- High albedo (reflect incoming shortwave radiation – cooling effect)
describe cloud impact on earth’s radiation budget
Clouds (H20) – complex effects on earths radiation budget
- High albedo (cooling)
- Absorb longwave radiation (warming, greenhouse gases)
why is radiation balanced
Light energy (radiation from sun) overall balances the energy going out because of dynamic
balance in temperature
how is incoming solar radiation budgeted?
Incoming solar radiation (shortwave)=100
- 30% reflected back in space (backscatter by air and clouds)
- 23% absorbed by atmosphere
- 50% reaches earth (less than 1% used by photosynthesis)
why is earth radiatively balanced
As a global long-term average, Earth is close to a state of radiative balance that amount of
incoming (shortwave) = amount of outgoing (shortwave and longwave)
atmosphere radiation budget?
Above atmosphere: 100=30+70 thus balanced b/c of thermodynamics
- Atmosphere: 156 input =156 output
- Surface: 145 input =116 output
what is convection? divided into?
: Heat transfer by turbulent movement of air and water
sensible and latent heat flux
define latent heat flux
Latent heat flux: energy transferred between a surface and the atmosphere by the
evaporation of water or the condensation of water vapor (phase change)
define sensible heat flux
Sensible heat flux: energy conducted from a warm surface to the air immediately above it
and moved upward to the atmosphere (no phase change
define natural greenhouse effect. what is its function?
Natural Greenhouse Effect: warming of atmosphere due to atmospheric absorption (by
radiatively active gases) of longwave radiation
-Maintains earth @ 15 degrees Celsius; without NGHE earth would be @33
degrees colder
What are radiatively active gasses?
Radiatively Active Gases: absorb and re-radiate long wave radiation emitted by Earth (H20,
CO2, CH4, N2O, O3, CFCs)
define mean residence times
Mean residence times (MRT): total mass divided by the flux into or out of the atmosphere over a
given time period
MRT for N2, O2, CO2?
N2 MRT=13 million years
- O2 MRT=10,000 years
CO2 MRT=5 years
what is spatial variation in climate due to
atmospheric structure
describe troposphere?
Ends approximately 10-16km
- Temp declines with height
- Heated from below; absorbs LW radiation emitted from Earth
- WEATHER
describe stratosphere
Above troposphere (to approximately 48km)
- Temp increased with height
- Heated from above (SW solar)
- UV protector, contains O3 which absorbs UV radiation
describe stratopause
- Absorption of incoming radiation by the oxygen
- Filtering of UV radiation takes place
describe thermosphere
Thermosphere:
- Increase in temp b/c of UV
