Energy - Budget Physics Flashcards
What drives atmosphere physics?
Solar energy absorption
What is the equilibrium of the earth-atmosphere system?
Energy recieved of SW visble poriton, re-emitted equally as LW infrared.
What are the two fates of incoming solar radiation?
Reflection by albedo.
Absorption by EA system.
What do estimates of Earth temperature by thermal equilibrium equate to?
255K or -18 degrees
What is Earth temperature when GHG are taken into account?
288K or 14 degree
Where is LW radiation re-emitted?
Middle of troposphere
What drives motion of the atmosphere?
Atmospheric energy transfer.
During infrared transfer from surface to troposphere, what forms does it take?
Sensible heat and Latent heat.
When does latent heat occur?
When water vapor condenses, releasing heat of vaporization.
What is the composition of solar radiation?
341 W where 102 reflects, 161 absorbed by surface.
What is composition of outgoing infrared radiation?
396 W, 40 through atmopsheric radiation and 333 back radiation by GHG
How is excess LW radiation balance?
Re-radiation of LW by GHG re-emission.
What does GHG re-emission result in?
Surplus of energy at 106 W
What further balances excess LW?
Latenet and sensible heat.
What must energy budget be for thermal equilbrium?
Zero
What temperature would earth have to be without latent and sensible heat?
50k warmer.
How much SW is absorbed by atmosphere?
68 W
How is Net Radiative Forcing of Surface calculated?
SW absorption + LW absorption from atmosphere - LW emission, = 106W
How is Net Radiatve Forcing of Atmopshere calculated?
SW absorption + LW absorption from surface - LW emission to surface - LW emission to space = -106W
Net Radiative Forcing
Change when amount of energy entering Earths atmosphere is different from amount of energy leaving it.
What motion does solar/infrared radiation influence?
Vertical
Why is horizontal transfer less uniform?
Must take into account surface properties, geometry and cloud cover.
Optical Properties
Defines how a material interacts with light.
How does incident solar radiation difffer in higher latitudes compared to equatorial?
Perpendicular to equator, whilst at different angles at higher latitudes.
How does TOA pencil distribute in higher latitudes?
Obliquely
What does oblique TOA distribution at higher latitudes mean?
Energy flux entering TOA is different across the incdience.
Pencil of Rays
A geometric construct describing a beam/portion of a beam of EM radiation or charged particles, in the form of a narrow cylindrical beam.
Atmospheric Insolation
Amount of solar radiation recieved by the planet at the TOA
What is insolation dependent on?
Solar zenith angle and day length, both varaible by season and locaiton.
Solar Zenith Angel
The angle between suns ray and vertical direction.
When does insolation maximise at the equator?
At the equinox, decreasing poleward.
How does SW travel distance differ in equator vs higher latitudes?
Direct at equator, at an angle at higher latitudes.
How does albedo differ across earth?
Less at equator due to less ocean coverage, absorbing more SW, whilst higher latitudes have more albedo due to ice covering.
How is tropics supplmeneted in albedo?
Increased albedo due to storm tracks.
How does OLR relate at the equator?
More clouds thus more albedo, whilst at subtropics surrounding convective centres have higher OLR.
Why do subtropics have higher OLR?
Cloud formation inhibition due to sinking motion, compensating rising motion inside ITCZ
How is thermal equilibrium maintained despite differences in latitude heating/cooling?
General circulation.
Solar Zenith Angle
Describes angle between the sun rays and the vertical axis of the planetary body.
Solar Azimuth Angle
This measures angle of the sun by the horizontal plane.
Why is zenith angle important?
In intensity of radiation we recieved from the sun
Whay causes south/north latitude season variation?
The zenith angle
Thermal Equilibirum
Describes how two systems in diathermic contact cause changes in the system by the passage of heat energy.
What is thermal equilibrium determined by?
Zeroth law of thermodynamics
