Development of Solar Channel Calibration for COMS and ...
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Byung-Ju ‘B.J.’ Sohn School of Earth and Environmental Sciences Seoul University, Korea [email protected] Development of Solar Channel Calibration for COMS and Application to MTSAT-1R
Transcript of Development of Solar Channel Calibration for COMS and ...
Byung-Ju ‘B.J.’ Sohn School of Earth and Environmental Sciences
Seoul University, [email protected]
Development of Solar Channel Calibration for COMS and
Application toMTSAT-1R
Calibration coefficientsCalibration coefficientsMonitoring parameters
(Mean Bias,RMSE)
Monitoring parameters(Mean Bias,
RMSE)
Twice a month
VISCO IRCVISCD VISCC
Simulated radiances vsCOMS digital counts
Simulated radiances vsCOMS digital counts
NCEP SSWNCEP TPW
OMI Total ozonePigment concentration
MODIS AOT
6S6S
MODIS and COMS Response function
TIGR 2000
RTTOVRTTOV
NCEP TPWOMI Total ozoneMODIS BRDF
6S6S
MODIS cloud products(Cloud top pressure,
Effective radius,COT)
SBDARTSBDART
COMS counts vs MODISbrightness temp.
COMS counts vs MODISbrightness temp.
COMS countsGeometric data
MODIS radiancesGeometric data
Scene check
Clear Clear ClearCloudy
Daily dataacquisition
Criteria
Brightness @ band 1 20% 15% 15%
Brightness @ band 2 30% 25% 25%
Brightness @ band 4 10% 5% 5%
Annual mean σ 0.06 0.08 0.12
Spatial mean σ 0.06 0.08 0.08
NDVI 0.2 0.25 0.25
Simpson Desert
Nullabor Plain
Gibson Desert
Tanami Desert
Great Artesian Basin
Great Victoria Desert
Strzelecki Desert
Desert targets selection
Longitude
136.6 136.8 137.0 137.2 137.4 137.6 137.8 138.0
Latit
ude
-26.4
-26.2
-26.0
-25.8
-25.6
-25.4
-25.2
-25.0
A
B C DE FG H I
J
K
Selected targets
555 nm405060708090
100
SeaWiFS 6S Cal.
Julian Day in 20050 30 60 90 120 150 180 210 240 270 300 330 360
Erro
r (%
)
-20-10
0102030
670 nm
Rad
ianc
e (W
m -2
)
6080
100120140160180
SeaWiFS 6S Cal.
765 nm
Julian Day in 20050 30 60 90 120 150 180 210 240 270 300 330 360
6080
100120140160
SeaWiFS 6S Cal.
@ 555 nm@ 670 nm@ 765 nm
@ Target B
Error = (Cal. – Obj.)/Obj.X100
F
Erro
r
-60-40-20
0204060
G
Erro
r
-60-40-20
0204060
H
Erro
r (%
)
-60-40-20
0204060
I
Julian Day in 20050 30 60 90 120 150 180 210 240 270 300 330 360
Erro
r (%
)
-60-40-20
020406080
B
Erro
r (%
)
-60-40-20
0204060
C
Erro
r (%
)
-60-40-20
0204060
D
Erro
r (%
)
-60-40-20
0204060
E
Julian Day in 20050 30 60 90 120 150 180 210 240 270 300 330 360
Erro
r (%
)
-60-40-20
0204060
@ 555 nm@ 670 nm@ 765 nm
Results @ other targets
Spectral difference : MODIS vs. MTSAT 1R
Conversion Spectral BRDF
MODIS BRDF Parameters
ASTERSpectral albedo
Wavelength [μm]
0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 2.2
Surf
ace
albe
do
0.0
0.2
0.4
0.6
Wavelength [μm]
0.5 1.0 1.5 2.0 2.5
Surf
ace
albe
do
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Original ASTERAdjusted ASTERMODIS
Type Selection2, MODIS ASTERm b Rα α= +
Spectral BRDF parameter
, , ( , target,time)iso vol geof λ
Adjustment
αλ
ASTER spectral albedo@solar zenith angle = 10o
),,( vs φθθ
Spectral conversion
0
07.337~344
0 100 200 300 400 5000
50
100
150
200 2
200 2
Application to MTSAT 1R
MODIS BRDF Products• MODIS BRDF parameters
(MOD43C1) converted spectral BRDF parameters
• Temporal resolution : every 8 days
• Spatial resolution :0.05°
X 0.05°
MTSAT 1R HRIT• Full disk observation • Geometric and radiometric calibration done• 10 bit, (Digital count from 1 to 1024)• Spatial resolution 1 X 1 km2
Digital Count
Sim
ulat
ed R
adia
nce
(Wm
-2μm
-1sr
-1)
07.313~320
0 100 200 300 400 5000
50
100
150
20007.321~328
0 100 200 300 400 5000
50
100
150
20007.329~336
0 100 200 300 400 5000
50
100
150
20007.337~344
0 100 200 300 400 5000
50
100
150
20007.345~352
0 100 200 300 400 5000
50
100
150
20007.353~360
0 100 200 300 400 5000
50
100
150
200
07.361~365
0 100 200 300 400 5000
50
100
150
20008.001~008
0 100 200 300 400 5000
50
100
150
20008.009~016
0 100 200 300 400 5000
50
100
150
20008.017~024
0 100 200 300 400 5000
50
100
150
20008.025~032
0 100 200 300 400 5000
50
100
150
20008.033~040
0 100 200 300 400 5000
50
100
150
200
08.041~048
0 100 200 300 400 500
Sim
ulat
ed R
adia
nce
(Wm
-2 μ
m-1
sr-1
)
0
50
100
150
20008.049~056
0 100 200 300 400 5000
50
100
150
20008.057~064
0 100 200 300 400 5000
50
100
150
20008.065~072
0 100 200 300 400 5000
50
100
150
20008.073~080
0 100 200 300 400 5000
50
100
150
20008.081~088
0 100 200 300 400 5000
50
100
150
200
08.089~096
0 100 200 300 400 5000
50
100
150
20008.097~104
0 100 200 300 400 5000
50
100
150
20008.105~112
0 100 200 300 400 5000
50
100
150
20008.113~120
0 100 200 300 400 5000
50
100
150
20008.121~128
0 100 200 300 400 5000
50
100
150
20008.129~136
0 100 200 300 400 5000
50
100
150
200
08.137~144
0 100 200 300 400 5000
50
100
150
20008.145~152
0 100 200 300 400 5000
50
100
150
20008.153~160
Digital count0 100 200 300 400 500
0
50
100
150
20008.161~168
0 100 200 300 400 5000
50
100
150
20008.169~176
0 100 200 300 400 5000
50
100
150
20008.177~184
0 100 200 300 400 5000
50
100
150
200
MTSAT 1R Radiance vs. Digital count
Provided cal. coeff.Regression line
Simulate radiance vs. Digital count
JMA providedCalibration coefficients
2007.11
0 100 200 300 400 500
Sim
ulat
ed R
adia
nce
0
50
100
150
2002007.12
0 100 200 300 400 5000
50
100
150
2002008.01
0 100 200 300 400 5000
50
100
150
2002008.02
0 100 200 300 400 5000
50
100
150
200
2008.03
0 100 200 300 400 5000
50
100
150
2002008.04
0 100 200 300 400 5000
50
100
150
2002008.05
Digital Count 0 100 200 300 400 500
0
50
100
150
2002008.06
0 100 200 300 400 5000
50
100
150
200
2007 2008 Month
Nov Dec Jan Feb Mar Apr May Jun
CAL
Coe
ff.
0.400.420.440.46
2007 2008 Month
Nov Dec Jan Feb Mar Apr May Jun
R2
0.96
0.98
1.00
2007 2008 Month
Nov Dec Jan Feb Mar Apr May Jun
RM
SE
2.00
4.00
6.00
8.00
Monthly linear regressionwith a fixed intercept as 0
Selection of DCCs
Considering seven temperature profiles, cold CTT less than 190K can be explained only by DCCs involving strong upward motion lacking of exchange with environmental air.
Temperature (K)
150 200 250 300 350
Hei
ght (
km)
0
20
40
60
80
100AIRS JAN2007 TROMLSMLWSASSAWUS62
190K
Temperature profiles
TB11
≤ 190K
SEVIRI 0.640 μm Image
Criteria: TB11 ≤
190K, STD9×9 of TB11 ≤
1K
COT, Re Characteristics of DCCs (TB ≤ 190K) from MODIS
More than 90% pixels show COT=100, which means that real COT could be larger than 100.
65.3%About 70% of pixels show COT > 150.
Sensitivity of 0.646 μm reflectance to COT
@ λ
= 0.64 μm re = 15 μm, x =150re = 20 μm, x = 200re = 25 μm, x = 250
Sensitivity of 0.646 μm reflectances to COT (SZA=30°)
Cloud bidirectional reflectance distribution function (BRDF) varies up to 5% when COT increases from 100 to 200 while BRDF changes up to 2.5% when COT increases from 200 to 400.
If we assume the COT to be 200 while real COTs range from 100 to 400, then BRDF error caused by uncertain COT values would be less than 5%.
Sensitivity of 0.646 μm reflectance to re (SZA=30°, COT=200)
Error range < ±2%
Satellite data
Well-calibrated IR band (11 μm)
TB11
Selected DCC pixels
Assumption of input parametersCOT=200, re = 20 μm,
Cloud height from TB11Standard atmospheric profile
Simulated visible radiances
Threshold conditions
Yes
No
Observed visible radiances
Vicarious calibration(Monitoring of pre-existing calibration system)
Cloud radiative transfer modeling
Visible band (0.6 μm)Same FOV
DCC-based vicarious calibration for visible channels
Simulated MODIS reflectances (re =20 μm, COT=200 )Terra Aqua
(Cal. - Obs.)/Obs. x 100 (%)
-30-20-100102030
Freq
uenc
y (%
)
0
5
10
15
20
25
30JAN 2006FEB 2006MAR 2006APR 2006MAY 2006JUN 2006
(Cal. - Obs.)/Obs. x 100 (%)
-30-20-100102030
Freq
uenc
y (%
)
0
5
10
15
20
25
30JAN 2006FEB 2006MAR 2006APR 2006MAY 2006JUN 2006
MODIS Band 1 (0.646 μm)
Observed reflectance
0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
Cal
cula
ted
refle
ctan
ce
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
-5%
+5%
MODIS Band 1 (0.646 μm)
Observed reflectance
0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2
Cal
cula
ted
refle
ctan
ce
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
-5%
+5%
Terra Aqua
MO
DIS
ban
d 1
(0.6
46 μ
m) R
adia
nce
300
350
400
450
500
550
ObservedCalculated
Julian day
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180
Rel
ativ
e er
ror (
%)
-10
-5
0
5
10
# of
pix
els
0
2000
4000
6000
8000
10000
12000
ERROR (%) = (cal. – obs.)/obs. X 100 (%)
Time series of simulated vs. observed MODIS radiance(Terra)
MO
DIS
ban
d 1
(0.6
46 μ
m) r
adia
nce
300
350
400
450
500
550
observedcalculated
Julian day
0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180
ER
RO
R (%
)
-10
-5
0
5
10
# of
pix
els
0
2000
4000
6000
8000
10000
12000
Time series of simulated vs. observed MODIS radiance(Aqua)
ERROR (%) = (cal. – obs.)/obs. X 100 (%)
