Validation of the forward/inverse physical scheme
ϕ-IASI
with NAST-I and IMG data.
A. Carissimo
G. Grieco
G. Masiello
DIFA: Department of Environmental
Engineering and Physics.
University of Basilicata. Potenza, Italy.
C. Serio
U. Amato
I. DeFeis
IAC: Institute of Applied Mathematics.
CNR, Napoli, Italy
V. Cuomo
M. Viggiano
IMAA: Institute of Methodology for
Environmental Analysis. CNR.
Tito Scalo, Potenza, Italy.
ITSC-15, Maratea, Italy, 3-10
October 2006
Forward/Inverse Tools
The φ-IASI package
„
σ-IASI: forward model
δ-IASI: physical inverse scheme
ν2-IASI: neural network inversion scheme
ε-IASI: EOF based regression scheme
„
γδσ-IASI: Cloud Detection Scheme
„
„
„
„
„
Masiello et al. JQSRT, Vol 77/2, 131-148, 2003
Masiello, et al. Appl. Opt. 43, 2004
ITSC-15, Maratea, Italy, 3-10 October 2006
REFERENCE FRAME
„
IASI project: Infrared Atmospheric
Sounding Interferometer
Fourier
Transform spectrometer with a
sampling rate of 0.25 cm-1
spectral coverage: 640 to 2760 cm-1
„
METOP/1, launch 7 October 2006 (?)
(ESA/EUMETSAT EPS programme).
ITSC-15, Maratea, Italy, 3-10 October
2006
IMG: Interferometric Monitoring of Greenhouse Gases
(0.05 cm-1 sampling rate), ADEOS/1 platform
ITSC-15, Maratea, Italy, 3-10 October 2006
NAST-I observations from the CAMEX/3 and EAQUATE
experiments
NAST-I (NPOESS Airborne Sounder Testbed, infrared interferometer)
Spectral sampling of ≈ 0.24 cm-1
Spectral coverage witch matches that of IASI (645 to
2760 cm-1).
‰
CAMEX 3 (Convection and Moisture Experiment 3)
„
‰
Data acquired during the Atlantic basin tropical cyclone field
validation NASA ER-2 flight (during local nighttime,
September 13-14, 1998) over Andros Island, Bahamas.
EAQUATE (European AQUA Thermodynamic
Experiment)
„
Data acquired during the Italian field validation Proteus flight
(3-11 September, 2004)
ITSC-15, Maratea, Italy, 3-10 October 2006
σ-IASI Consistency Check
based on
NAST-I scan #298 (Nadir)
ITSC-15, Maratea, Italy, 3-10
October 2006
ITSC-15, Maratea, Italy, 3-10
October 2006
ITSC-15, Maratea, Italy, 3-10
October 2006
ITSC-15, Maratea, Italy, 3-10
October 2006
ITSC-15, Maratea, Italy, 3-10
October 2006
Eaquate Campaign
NAST-I spectrum recorded over a
plant canopy
ITSC-15, Maratea, Italy, 3-10
October 2006
AFTER: Mark Shephard, Tony Clough, Jennifer Delamere, Karen
Cady-Pereira, and Eli Mlawer,Atmospheric and Environmental Research
(AER), Inc.,
http://bernath.uwaterloo.ca/ASSFTS/Media/ASSFTS%20Presentations/pdfPres/Shephard.pdf
ITSC-15, Maratea, Italy, 3-10
October 2006
The inverse scheme
( v − v g )t L( v − v g )
Min!
Subject to :
( R − F ( v )) t S −1 ( R − F ( v )) ≤ χ α2
L = B
−1
[
Q( v) = (R − F ( v)) S (R − F ( v)) + γ ( v − v g ) B ( v − v g )
t
−1
t
vˆ n + 1 = vˆ n − ( ∇ v ∇ v Q ) − 1 ( ∇ v Q )
ITSC-15, Maratea, Italy, 3-10 October
2006
−1
]
Rodgers-like Approach
Tikhonov-like Approach
vˆ − v 0 = (γ B −1 + K t S −1K ) −1 ( K t S −1d − γ B −1q 0 )
q0 = v0 − v g
S v = (γ B −1 + K t S −1K ) −1 (γ 2 B −1 + K t S −1K )( γ B −1 + K t S −1K ) −1
ITSC-15, Maratea, Italy, 3-10 October
2006
Transform the inverse solution to PC space trough SVD of
the resolving kernel:
(details in:
Carissimo et al, 2005, EMS, Vol. 20, 1111-1126
and
EUMETSAT Tech. Rep. EUM/CO/04/1285/RST, Final report, 2004)
−
1
2
1
2
G = S KB ; [U, Α, V] = svd (G)
Component - wise form :
⎧
⎪
αi2
αi
γ
⎪
ˆ
c
(i)
c
i
c
i
c (i ); Rodgers - like
=
(
)
+
(
)
+
⎨
2 true
2 ε
2 b
γ + αi
γ + αi
γ + αi
⎪
⎪
⎩
ITSC-15, Maratea, Italy, 3-10
October 2006
0
0
100
100
γ=0.7
Pressure [mbar]
200
EAQUATE EXPERIMENT
F.G.
0
RAOB Brindisi
Physical Inversion
0
100
γ=1.0
200
100
γ=2.0
200
300
300
300
300
400
400
400
400
500
500
500
500
600
600
600
600
700
700
700
700
800
800
800
800
900
d.o.f.=7.5
900
1000
d.o.f.=7.2
900
1000
-4
-3
-2
10 10 10
-1
10
0
1
10 10
d.o.f.=6.5
900
1000
-4
-3
-2
10 10 10
-1
10
0
1
10 10
γ=70
200
d.o.f.=5.0
1000
-4
-3
-2
10 10 10
-1
10
ITSC-15, Maratea, Italy, 3-10
water
vapour2006
[g/kg]
October
0
1
10 10
-4
-3
-2
10 10 10
-1
10
0
1
10 10
Physical retrieval, H2O
(Initialization by EOF Regression)
EAQUATE experiment
42 NAST-I
spectra have
been inverted
0
100
200
Pressure (mbar)
300
Brindisi RAOB
Retrieved
400
500
600
700
800
900
1000
0
2
4
6
8
10
12
14
H2O mixing ratio (g/kg)
ITSC-15, Maratea, Italy, 3-10
October 2006
16
18
20
Physical retrieval, Temperature
(Initialization by EOF Regression)
EAQUATE experiment
42 NAST-I
spectra have
been inverted
0
100
200
Pressure (mbar)
300
400
500
Brindisi RAOB
Retrieved
600
700
800
900
1000
200
210
220
230
240
250
260
270
Temperature (K)
ITSC-15, Maratea, Italy, 3-10
October 2006
280
290
300
Retrieval Exercise based on NAST-I scan #298 spectrum
FG: from EOF
Regression; Truth: RAOB2
ITSC-15, Maratea, Italy, 3-10
October 2006
Retrieval Exercise based on NAST-I scan #298 spectrum
FG: from EOF
Regression; Truth: RAOB2
ITSC-15, Maratea, Italy, 3-10
October 2006
Physical retrieval, Temperature
(Initialization by EOF Regression)
CAMEX/3
294 NAST-I
spectra have
been inverted
ITSC-15, Maratea, Italy, 3-10
October 2006
Physical retrieval, H2O
(Initialization by EOF Regression)
CAMEX/3
294 NAST-I
spectra have
been inverted
ITSC-15, Maratea, Italy, 3-10
October 2006
Ozone Retrieval from IMG tropical soundings
(details in: Grieco et al JQSRT, Volume 95, Issue 3 (2005) 331-348)
ITSC-15, Maratea, Italy, 3-10
October 2006
Main Conclusions
„
„
ϕ-IASI does work
The quality of state-of-art radiative transfer seems to
be good enough to meet Temperature and H2O
IASI mission objective.
‰
‰
„
In particular no radiosonde tuning was needed to yield
accurate retrieval
Some problems do exist and are mostly confined to the
short wave side of the spectrum (forward modeling?,
spectroscopy?, N2O climatology?)
The Physical inverse scheme improves T and H2O
retrieval independently of the initialization scheme.
ITSC-15, Maratea, Italy, 3-10 October 2006