Environmental Engineering Reference
In-Depth Information
14
12
10
8
Day
Night
6
4
2
0
−
20
−
15
−
10
−
5
0
5
10
(T11
−
T3.9) (K)
Fig. 19.4
(
T
s
T
11
) vs. (
T
11
T
3.9
) distribution, where
T
11
and
T
3.9
are the GOES brightness
temperature at channels 4 and 2 and
T
s
is the skin temperature
Surface Type
Configuration
Input (looping)
parameters
Atmospheric
profiles
MODTRAN 4.3
Simulation
Radiative Transfer Model (RTM)
Start
Simulation
Analysis
TOA
Brightness
temperature
TOA
radiances
Fig. 19.5
Radiative transfer simulation procedure
The coefficients in (
19.41
) may depend on surface type or emissivity, since the
surface bidirectional reflectivity is related to it. In the window channels, the major
absorbing gas is the water vapor, but neglect of absorption from CH
4
and N
2
O in the
GOES 3.9-
m channel can contribute to additional errors. Estimating atmospheric
CH
4
and N
2
O amounts is difficult. To allow for the effect of all absorbers in this
channel, we propose to use the brightness temperature
T
3.9
to replace
μ
ρ
b
θ
s
; θ
ð
Þ
us in
(
19.41
), by modifying the coefficients in this equation as follows:
T
0
3
:
9
T
3
:
9
c
0
0
ðlÞþc
0
1
ðlÞT
3
:
9
cos
θ
s
(19.42)
Search WWH ::
Custom Search