Lecture 3 Extra-terrestrial Shortwave Radiation • Reflected shortwave ...

Lecture 3

Extra-terrestrial Shortwave Radiation    

Reflected shortwave radiation is planetary albedo Albedo is NOT longwave radiation α=1, body reflects everything α=0, body reflects nothing (absorbs)

Planetary Albedo  

Typically around 31% of incoming solar radiation in reflected or backscattered by the atmosphere Typically 23% of incoming solar radiation is absorbed by the atmosphere

Terrestrial Longwave Radiation

 

Deficit on energy in the atmosphere, and a surplus at the surface Transfer mechanisms are through sensible (7) and latent heat (24)

Convection Convection in the atmosphere is the vertical interchange of air masses in the atmosphere, taking thermal and latent energy with them 

Phase change of water

Free Convection: Warm/moist buoyant air rising through cooler (drier) air Forced Convection: Air mechanically forced upwards due to objects or topography

Latent Heat Process

ICE

LIQUID

Calculating Instantaneous Energy Balance Albedo = K↑/K↓ K↓= S (direct) + D (diffuse)

VAPOR

Rn = H + LE + G H = sensible heat flux LE = latent heat flux G = soil heat flux

Sign Convention Radiative Fluxes  

Positive when they represent a gain to the surface Rn, K, L fluxes

Non Radiative Fluxes  

Positive when they are directed away from the surface H, LE, G fluxes