Exchange Processe s Between the Earth‘s Surface and the Atmosphere

Exchange Processes Between the Earth‘s Surface and the Atmosphere

1. Energy budget2. Boundary layers3. Observations

Energy Budget at the SurfaceFrad

sfs = FSWs (1-A sfs)-T4+ FLW

Fradsfs is the net radiative flux,

FSWs is the short-wave radiation

A sfs is the albedo is the infrared emissivity,FLW

is the lnog-wave radiation (back radiation)

Climatic system:

Open componentsCoupling between individual componentsBoundary layers (fluxes of matter, energy and momentum)

From the conservation of energy for ideal surface it follows:

Fradsfs - FSH

-FLH -FG

-FM =0

FSH =is the sensible heat flux (differences in temperatures of the surface and the air)

FLH =LeE is the latent heat flux (mostly evaporation)

FG is the sensible heat flux to or from the soil/water (mainly due to heat conduction)

FM = LM(Ms -Fs), melting (Ms) and freezing (Fs) rates

For annual mean conditions: FG =0 and we have for land

Fradsfs - FSH

-LeE-LM(Ms -Fs) =0

zF

Kzt

Tc

zFcT

t

zTKF

FMLFFFFtH

G

G

SSmGLHSHsfsrad

s

)(

)(

Energy budget of a layer

This is valid if there are no sources or sinks of energy within the slab, c-specific heat

This is valid if and c are constant

Variations of temperature can be used to estimate the heat fluxes into the ground

Dynamic Structure of the Atmosphere

zuK

Newtonean law:

0* ln1)(

)(

zzu

kzu

zfKconst

Logaritmic layer

Exchange of Heat Trough Sensible Heat

0013.0

)0()()(

''

dh

hpSH

pHSH

pSH

CC

zzvCcFz

cKF

wcF

Eddy correlation approach

Bulk aerodynamicapproach

Exchange of Heat Trough Water Exchange/Evaporation

)0()()(

''

qzqzvCcEzqKE

wqE

ep

W

)()( zvzvCd

Cd is a function of stability, surface roughnes, etc.

v 0.02-0.04W/m2