MIPAS Validation Summary
Herbert Nett
- Plenary Session -
MIPAS Validation Review - ESRIN - 9–13 December 2002
ESTEC / EEM-PPP
Page 1
Measured NESR0
MIPAS NESR 0
(High Resolution Calibrated Spectrum)
1.0E-07
NESR (W cm -2 sr-1 cm)
In-Flight (223K)
Requirement
On-Ground (231K)
1.0E-08
1.0E-09
500
700
900
1100
1300
1500
1700
1900
2100
2300
2500
Wavenumber (cm -1)
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 2
Radiometric Performance
Radiometric Accuracy
Wavenumber range [cm-1]
value
In-flight validation
685 - 970
2 * NESRT+ 5 % [true source radiance]
Ok
1570 - 2410
2 * NESRT+ 1 % [true source radiance]
Ok
Dynamic range (BB source)
(0 – 230) K
Ok
 Critical aspects
 ice contamination on focal plane optics
 non-Linearity of detectors in bands A, AB and B
-> strongest impact in band A !
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 3
Level 2 algorithm verification: critical aspects
 variabilities in target gas signatures (latitudinal, day/night
dependencies, perturbed chemistry …)
 knowledge of systematic error sources (modelling of instrumental errors,
interfering species, spectroscopic errors, Non-LTE ...)
 code robustness wrt instrumental effects & extreme atmospheric conditions
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 4
Results of orbit #504 retrievals: all species
Altitude [km]
VMR (ppmv)
Water vapour
Ozone
CH4
HNO3
N 2O
NO2
Orbital coordinate [deg]
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 5
Summary: MIPAS Level 2 error budgets
Target
parameter,
species
retrieval
range [km]
temperature
estimated error (global average)
dominating error
(sys only)
ESD
Total
(random+sys)
12 - 68
1-2K
2–5K
ILS, Hitran, O3
pressure
12 – 68
1–3%
3–6%
Hitran, GAIN, O3,
O3
12 – 60
4 – 23 %
8 – 30 %
ILS, Tem, Hitran
HNO3
12 – 42
3 – 37 %
7 – 44 %
Hitran, Tem, ILS
H2 O
12 – 60
4 – 24 %
16 – 49 %
Hitran, GRA, Tem
CH4
12 – 60
6 – 20 %
11 – 29 %
Tem, GRA, Hitran
N2O
12 – 47
8 – 26 %
13 – 29 %
Tem, Hitran, GRA
NO2
24 – 47
11 – 27 %
13 – 65 %
NLTE, Tem, GRA
[ Extracted from presentation
A. Dudhia / U. of Oxford ]
GAIN: gain cal error
GRA: horizontal T gradient
ILS: ILS shape error
MIPAS Validation Review - ESRIN - 9–13 December 2002
Tem: temperature error
Hitran: spectrocopy error
NLTE: Non-LTE effects
Page 6
By: H. Oelhaf / FZ-IMK
MIPAS-B2 vs. MIPAS-Envisat Comparisons
-2 0 2210
215
220
225
230
235
240
245
250
255
260
1
-2
265
1
-1
0
1
2
10
MIPAS-B: 24-Sep-2002 22:21:42
MIPAS: 24-Sep-2002 22:07:49
Sonde: 24-Sep-2002 19:37
MIPAS-Difference
100
100
220
225
230
235
240
245
250
255
260
265
Pressure (hPa)
Pressure (hPa)
10
215
4
5
6
7
8
9
10
1
Aire: 24 September 2002
MIPAS-B: 24-Sep-2002 22:21:42
MIPAS: 24-Sep-2002 22:07:49
MIPAS-Difference
Temperature
-2 0 2210
3
1
10
10
HNO3
100
100
-2
-1
0
Temperature (K)
MIPAS Validation Review - ESRIN - 9–13 December 2002
1
2
3
4
5
6
7
8
9
10
HNO3 Volume Mixing Ratio (ppbv)
Page 7
NDSC /O3 sonde & MW radiometer
Payerne (av., after 13 Nov)
NDSC / Lidar
OHP
Lauder (NZ)
By: J.C. Lambert, V. Soebijanta, BIRA/IABS
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 8
By: A. Dethof / ECMWF
MIPAS temperatures
 Good agreement of MIPAS temperatures with ECMWF analyzed
temperatures over large part of stratosphere (diff < 2%)
 Largest differences at 0.1 hPa (ECMWF model top)
 MIPAS too cold at bottom end of profiles especially in tropics
(cloud contamination?). Improvement after upgrade on 13.11.2002.
 Very robust. Same features seen every week.
Global averages, 11.-17.11.2002
MIPAS
Departures
MIPAS - EC
ECMWF
Improvement
after 13.11.02
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 9
By: A. Dethof / ECMWF
MIPAS Ozone
 Reasonable agreement with ECMWF ozone over large part of stratosphere
 Some differences might be explained by known ECMWF model bias:
e.g. – tropical O3 max. lower in ECMWF than MIPAS
- 90-65ºN: ECMWF > MIPAS over large part of stratosphere
 Unrealistically large MIPAS ozone values in lower stratosphere
(cloud contamination?). Improvement after upgrade on 13.11.2002.
4.-10.11.02
ECMWF
25.11.-1.12.02
MIPAS
Improvement
after 13.11.02
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 10
Cloud top height distribution in MIPAS measurements
(~4100 profiles, 7 – 25 Sep 2002)
By: J. Remedios/
U. Of Leicester
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 11
MIPAS L2: Geophysical validation
Target parameter
T, H2O, O3
Category
Sat. I/C & assimilation:
ECMWF, UKMet Office,
BASCOE/4D, HALOE,
ODIN
Result / Status
T:
good agreement (typ < 2%)
O3: good, small bias (+ 1...2 ppmv)
H2O: 5 … 15% bias h > 55 km, < 20 km
T, H2O, O3, HNO3,
CH4, N2O, NO2
Balloons, aircrafts:
MIPAS-B2, TRIPLE (insitu) M-55 (IR/FIR & insitu)
T:
good agreement (~ 1K)
O3 :
good, small bias(+)
H2O: too high h > 55 km, too low < 20 km
HNO3: bias (-)
CH4 : bias (+) for h < 25 km
CH4, N2O, NO2: tendency to oscillations
H2O, O3, HNO3,
CH4, N2O, NO2
Ground-based:
good agreement for O3
FTIR, LIDAR, MWR
other species: analysis ongoing
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 12
MIPAS L2: Geophysical validation / summary
temperature:
O3 :
H2O:
HNO3:
CH4, N2O, NO2:
ACVT-MASI:
good agreement with correlative measurements
& analyses
generally good agreement, bias +1…2 ppmv (?) -> spect. database
too high > 55 km -> Non-LTE (?)
too low < 20 km
-> cloud contamination, MW choice, conv. thresholds
bias (-)
-> updated spectroscopic data (mipas_hitran v2 -> v3)
will yield ~ 10 % higher mixing ratios
tendency to vertical oscillations -> T error propagation (‘F’ - ‘R’ difference
in detector NL correction/band A)
“the MIPAS data set (including also HNO3, CH4, NO2) is the only data set that
is self-consistent and can be included in existing assimilation systems”
,
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 13
Retrieval altitude-range
-75°
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 14
Lessons learned / critical areas




potential for reduced total errors by extended MW selection (pT, H2O, …)
perturbations in non-regularised profile retrievals due to oscillations
in ‘fw’ – ‘rev’ sweep radiances
(re-check after enhanced NL correction scheme in place)
extension of retrieval height range towards higher and lower limb heights will
improve the profile accuracy also within the nominal height interval
inaccuracies in spectroscopic line data (incl. error correlations)
-> essential also for gephysical validation (HNO3 …)
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 15
Baseline modifications: L2 algorithm
subject
handle sweeps at low altitudes & low latitudes by constraining
base profile correction in pT
handling of single microwindow OMs
Status / IPF
PDS implementation
in progress
(-> Feb 2003, tbc)
recursive pT & H2O retrievals
cloud detection & filtering of L1B input during L2 pre-processing
report cloud index profiles in Level 2
report IG profile information in Level 2
extend retrieval range to < 12 km & 68 km
extend microwindow selection for pT & H2O
other modification (tbd, result of ACVT activities)
MIPAS Validation Review - ESRIN - 9–13 December 2002
approach:
Detailed definition &
prototyping
-> start early 2003 (tbc)
Page 16
MIPAS error budgets

Re-assess total budgets, take into account:
- mean profiles and variabilities of contaminants
- impact of assumed profile shape above highest tangent altitude
- impact of convergence thresholds
Reporting
ESD & temperature error propagation -> Level 2 products
Systematic components (HITRAN, NLTE, gain, ..)
-> ’off-line’ information, could be provided as TN & coded data sets (as
done for MIPAS Averaging Kernels)
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 17
Conclusions
• MIPAS in-flight calibration & characterisation tasks completed (some
activities & documentation under finalisation)
• geophysical validation: first intercomparison results available (ground-based,
balloon sensors, assimilation studies, …)
• instrument in excellent health, consolidated L0 -> L2 processing chain
• stable algorithm baseline (May ‘02->), only minor changes in aux data
• important update 13 Nov (LOS pointing correction, L2 tuning parameters)
• algorithm update in progress (pT/H2O loop, cloud detection)
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 18
Recommendations
• Level 1B
-> release ok
• Level 2:
-> release after update of IPF (incl. cloud detection,
pT-H2O iteration loop, mipas_hitran v.3.0)
• Essential:
supply MIPAS data users with
- total error budgets
- averaging Kernels
- spectroscopic database
- reports on geophysical validation campaigns
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 19
The MIPAS Calibration & Algorithm Verification Team
P. Mosner/R.Gessner
Astrium/D
G. Perron, G. Aubertin ABB BOMEM
Th. Fiksel
DJO
S. Bartha
Astrium/D
B. Carli, P. Raspollini
IFAC-CNR
M. Carlotti, M. Ridolfi U. of Bologna
B. Dinelli
ISAC-CNR
A.Dudhia, C.D. Rodgers Univ. of Oxford
J.M. Flaud
LPM/Paris
M. Hoepfner/H. Oelhaf FZ-IMK
T.v. Clarmann
FZ-IMK
M. Lopez-Puertas
IAA
M. Birk/G. Wagner
DLR-IMF
J.J. Remedios/R. Spang Univ. of Leicester
G. Schwarz
DLR-IMF
[ instrument engineering / operations ]
[ ESL / Level 1B ]
[ L1B&2 s/w engineering ]
[ L2 s/w engineering ]
[ ESL / Level 2 ]
[ ESL / Level 2 ]
[ ESL / Level 2 ]
[ ESL / Level 2; project AO # 323 ]
[ ESL / Level 2 ]
[ ESL / Level 2 ]
[AO#145 & AMIL2DA / L1B&2 analysis ]
[ project AO # 304 / L2 analysis ]
[ project AO # 652 / L1B analysis ]
[ project AO # 357 / L1B&2 analysis ]
[ ESL / Level 2 ]
ESTEC: J.C. Debruyn, A. Burgess (now U. Oxford), J. Langen, M. Sanchez, H. Nett
ESOC: A. O’Connell (now EUMETSAT), D. Patterson , F. Diekmann, A. Rudolph
MIPAS Validation Review - ESRIN - 9–13 December 2002
Page 20