ATMOSPHERIC TEMPERATURE SOUNDING. If radiation is selected in a sounding channel for which. and we define a function K(z) =. - PowerPoint PPT Presentation
dz dz d z T B L 0 ) ( )) ( , ( ) ( ATMOSPHERIC TEMPERATURE SOUNDING iation is selected in a sounding channel for which we define a function K(z) = dz d When the primary absorber is a well mixed gas (e.g. oxygen or CO 2 ) with known concentration it can be seen that the measured radiance is essentially a weighted average of the atmospheric temperature profile, or dz z K z T B L 0 ) ( )) ( , ( ) ( unction K(z) that defines this vertical average is known as a TING FUNCTION
Transcript
dzdz
dzTBL
0
)())(,()(
ATMOSPHERIC TEMPERATURE SOUNDING
If radiation is selected in a sounding channel for which
and we define a function K(z) =
dz
d
When the primary absorber is a well mixed gas (e.g. oxygen or CO2) with known concentration it can be seen that the measured radiance is essentially a weighted average of the atmospheric temperature profile, or
dzzKzTBL
0
)())(,()(
The function K(z) that defines this vertical average is known as a
WEIGHTING FUNCTION
CO2slicing: weighting functions
Bands w/greater CO2 absorptionhave weighting functions more
sensitive to high clouds
S. Platnick, ISSAOS ‘02Example spectra (~ 12.65-14 µm)
MODIS CO2 band weighting functions
1000
100
10
0.0 0.2 0.4 0.6 0.8 1.0
Pre
ssu
re (
mb
)
Weighting Function dt(,p)/d ln p
Channel 32 33 34 35 36
Central Wavelength (µm)
12.020 13.335 13.635 13.935 14.235
36
1.2
35
34
33
321000
100
10
0.0 0.2 0.4 0.6 0.8 1.0
Pre
ssu
re (
mb
)
Weighting Function dt(,p)/d ln p
Channel 32 33 34 35 36
Central Wavelength (µm)
12.020 13.335 13.635 13.935 14.235
36
1.2
35
34
33
32
BT in and out of clouds for MODIS CO2 bands
S. Platnick, ISSAOS ‘02
1000
100
10
0.0 0.2 0.4 0.6 0.8 1.0
Pre
ssu
re (
mb
)
Weighting Function dt(,p)/d ln p
Channel 32 33 34 35 36
Central Wavelength (µm)
12.020 13.335 13.635 13.935 14.235
36
1.2
35
34
33
321000
100
10
0.0 0.2 0.4 0.6 0.8 1.0
Pre
ssu
re (
mb
)
Weighting Function dt(,p)/d ln p
Channel 32 33 34 35 36
Central Wavelength (µm)
12.020 13.335 13.635 13.935 14.235
36
1.2
35
34
33
32
CO2slicing: weighting functions
Bands w/greater CO2 absorptionhave weighting functions more
sensitive to high clouds
S. Platnick, ISSAOS ‘02Example spectra (~ 12.65-14 µm)
MODIS CO2 band weighting functions
1000
100
10
0.0 0.2 0.4 0.6 0.8 1.0
Pre
ssu
re (
mb
)
Weighting Function dt(,p)/d ln p
Channel 32 33 34 35 36
Central Wavelength (µm)
12.020 13.335 13.635 13.935 14.235
36
1.2
35
34
33
321000
100
10
0.0 0.2 0.4 0.6 0.8 1.0
Pre
ssu
re (
mb
)
Weighting Function dt(,p)/d ln p
Channel 32 33 34 35 36
Central Wavelength (µm)
12.020 13.335 13.635 13.935 14.235
36
1.2
35
34
33
32
ρ1,T1,P1
Cross section [m2]
ρ2,T2,P2
>
ρ3,T3,P3
>
ρ4,T4,P4
>ρ5,T5,P5
>
CO2slicing: weighting functions
Bands w/greater CO2 absorptionhave weighting functions more
sensitive to high clouds
S. Platnick, ISSAOS ‘02Example spectra (~ 12.65-14 µm)
MODIS CO2 band weighting functions
1000
100
10
0.0 0.2 0.4 0.6 0.8 1.0
Pre
ssu
re (
mb
)
Weighting Function dt(,p)/d ln p
Channel 32 33 34 35 36
Central Wavelength (µm)
12.020 13.335 13.635 13.935 14.235
36
1.2
35
34
33
321000
100
10
0.0 0.2 0.4 0.6 0.8 1.0
Pre
ssu
re (
mb
)
Weighting Function dt(,p)/d ln p
Channel 32 33 34 35 36
Central Wavelength (µm)
12.020 13.335 13.635 13.935 14.235
36
1.2
35
34
33
32
CO2slicing: weighting functions
Bands w/greater CO2 absorptionhave weighting functions more
sensitive to high clouds
S. Platnick, ISSAOS ‘02Example spectra (~ 12.65-14 µm)
MODIS CO2 band weighting functions
1000
100
10
0.0 0.2 0.4 0.6 0.8 1.0
Pre
ssu
re (
mb
)
Weighting Function dt(,p)/d ln p
Channel 32 33 34 35 36
Central Wavelength (µm)
12.020 13.335 13.635 13.935 14.235
36
1.2
35
34
33
321000
100
10
0.0 0.2 0.4 0.6 0.8 1.0
Pre
ssu
re (
mb
)
Weighting Function dt(,p)/d ln p
Channel 32 33 34 35 36
Central Wavelength (µm)
12.020 13.335 13.635 13.935 14.235
36
1.2
35
34
33
32
CO2slicing: weighting functions
Bands w/greater CO2 absorptionhave weighting functions more
sensitive to high clouds
S. Platnick, ISSAOS ‘02Example spectra (~ 12.65-14 µm)
