Upload
warren
View
21
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Exchange Processe s Between the Earth‘s Surface and the Atmosphere. Energy budget Boundary layers Observations. Climatic system: Open components Coupling between individual components Boundary layers (fluxes of matter, energy and momentum). Energy Budget at the Surface - PowerPoint PPT Presentation
Citation preview
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