ACE Spectroscopic Issues for Spectroscopic Issues for the Atmospheric the Atmospheric Chemistry Experiment Chemistry Experiment (ACE) (ACE) Chris Boone, Kaley Walker, and Chris Boone, Kaley Walker, and Peter Bernath Peter Bernath HITRAN meeting HITRAN meeting June, 2008 June, 2008
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ACE Spectroscopic Issues for the Atmospheric Chemistry Experiment (ACE) Chris Boone, Kaley Walker, and Peter Bernath HITRAN meeting June, 2008.
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ACE Spectroscopic Issues for the Spectroscopic Issues for the Atmospheric Chemistry Atmospheric Chemistry
Experiment (ACE)Experiment (ACE)
Chris Boone, Kaley Walker, and Peter Chris Boone, Kaley Walker, and Peter BernathBernath
Satellite mission for remote sensing of Satellite mission for remote sensing of the Earth’s atmosphere, with a primary the Earth’s atmosphere, with a primary focus on Arctic ozonefocus on Arctic ozone
Developed by the Canadian Space Developed by the Canadian Space AgencyAgency
Launched August 2003, science Launched August 2003, science operations began February 2004operations began February 2004
Operating well, no major problems yet.Operating well, no major problems yet. Currently funded through April 2009.Currently funded through April 2009.
ACESolar OccultationSolar Occultation
ACE
InstrumentsInstruments
Infrared Fourier Transform Spectrometer Infrared Fourier Transform Spectrometer operating between 2 and 13 microns with a operating between 2 and 13 microns with a resolution of 0.02 cmresolution of 0.02 cm-1-1 ( ( 25 cm MPD) 25 cm MPD)
2-channel visible/near infrared Imagers, 2-channel visible/near infrared Imagers, operating at 0.525 and 1.02 micronsoperating at 0.525 and 1.02 microns
In July 2006, HITRAN released a complete replacement for HNO3, based on the work of Flaud et al., [2006] “MIPAS database: Validation of HNO3 line parameters using MIPAS satellite measurements”, ACP, 6, 5037-5048, 2006
How well does this new linelist describe the HNO3 absorption?
Examples of missing HNOExamples of missing HNO33 bandsbands
Fits to MkIV balloon spectra acquired at 22-23 km tangent altitude inside the polar winter vortex showing various missing HNO3 bands.
nu1+nu9
nu12nu3
HNOHNO33 Summary (Geoff Toon) Summary (Geoff Toon)July 2006 HNO3 update is an improvement on HITRAN 2004:• Reduced inconsistencies between 900 and 1700 cm-1 bands• Improved fits to the 900 and 1200 cm-1 regions• Introduced a J-dependent widths (900 cm-1 region only)
But serious deficiencies remain:• nu3 band at 1300 cm-1 (the strongest) is still problematic• Strength of 1205 cm-1 band is too small (20%)• No lines above 1770 cm-1 (e.g. nu1 fundamental at 3550 cm-1)• Missing the vast majority of overtone and combination bands, • Missing most hot bands and all heavy isotopologs• HNO3 widths are all constant, except for the 900 cm-1 region
HNO3 spectroscopic deficiencies are a major obstacle to further progress in the use of solar occultation spectra to measure or detect trace gases (e.g. SO2, HDO, H2CO, HOCl, OH, HO2)
ACEPseudolinesPseudolines
-80 -60 -40 -20 0 20 40 60 800
5
10
15
20
25
30
35
40
Latitude (degree)
Alt
itu
de
(km
)
5
10
15
20
25
30
35
40
45
50
55
COCl2 COClF
Eventually want real spectroscopic parameters (or cross sections) for these molecules. For now, pseudolines allow retrievals.
ACE
HH22O spectroscopic O spectroscopic parametersparameters
Below about 15 km, HBelow about 15 km, H22O lines in the ACE-O lines in the ACE-FTS spectra exhibit bad w-shaped residuals.FTS spectra exhibit bad w-shaped residuals.
At least partially deviations from the Voigt At least partially deviations from the Voigt lineshape, but there could also be a lineshape, but there could also be a contribution from poor spectroscopic contribution from poor spectroscopic parameters (very weak lines).parameters (very weak lines).
Very bad consistency between lines.Very bad consistency between lines. Determine parameters from the ACE-FTS Determine parameters from the ACE-FTS
spectra (not the ideal solution). spectra (not the ideal solution).
ACEHH22O (continued)O (continued)
Parameters of interest are the pressure Parameters of interest are the pressure broadening (including a temperature broadening (including a temperature dependence), intensity, and pressure shift.dependence), intensity, and pressure shift.
Using many different occultations, initially Using many different occultations, initially attempted to determine both broadening attempted to determine both broadening parameter and its temperature parameter and its temperature dependence, but that didn’t work out well dependence, but that didn’t work out well (took a week to converge, sometimes (took a week to converge, sometimes didn’t converge).didn’t converge).
Fix temperature dependence (HITRAN).Fix temperature dependence (HITRAN). Choose a single line for “calibration.”Choose a single line for “calibration.”
ACE
0
0.2
0.4
0.6
0.8
1
1.2
1987 1987.2 1987.4 1987.6
29.8 km
28.1 km
26.4 km
24.9 km
23.3 km
22.0 km
20.5 km
19.2 km
17.8 km
16.7 km
15.7 km
14.6 km
13.7 km
12.7 km-0.015
-0.01
-0.005
0
0.005
0.01
0.015
0.02
1987 1987.2 1987.4 1987.6
29.8 km
28.1 km
26.4 km
24.9 km
23.3 km
22.0 km
20.5 km
19.2 km
17.8 km
16.7 km
15.7 km
14.6 km
13.7 km
12.7 km
-0.015
-0.01
-0.005
0
0.005
0.01
0.015
0.02
1987 1987.2 1987.4 1987.6
29.8 km
28.1 km
26.4 km
24.9 km
23.3 km
22.0 km
20.5 km
19.2 km
17.8 km
16.7 km
15.7 km
14.6 km
13.7 km
12.7 km
HITRAN: pbhw = 0.0927
NEW: pbhw = 0.1000
All residuals shown are from sr10909 (a tropical occultation).
ACE
Does changing broadening Does changing broadening parameters affect VMR?parameters affect VMR?
Use the line at 1987.34 cm-1 to calibrate those at lower altitudes. Note: minimal occultation set. Final values will be derived from a set of 95 tropical occultations
0
0.2
0.4
0.6
0.8
1
1.2
1959.2 1959.3 1959.4 1959.5 1959.6 1959.7 1959.8
24.9 km
23.3 km
22.0 km
20.5 km
19.2 km
17.8 km
16.7 km
15.7 km
14.6 km
13.7 km
12.7 km
11.9 km
11.1 km
10.3 km
9.5 km
8.7 km
8.1 km
7.5 km
6.9 km
6.2 km
-0.02
-0.015
-0.01
-0.005
0
0.005
0.01
0.015
0.02
0.025
0.03
1959.2 1959.3 1959.4 1959.5 1959.6 1959.7 1959.8
24.9 km
23.3 km
22.0 km
20.5 km
19.2 km
17.8 km
16.7 km
15.7 km
14.6 km
13.7 km
12.7 km
11.9 km
11.1 km
10.3 km
9.5 km
8.7 km
8.1 km
7.5 km
6.9 km
6.2 km
-0.02
-0.015
-0.01
-0.005
0
0.005
0.01
0.015
0.02
0.025
0.03
1959.2 1959.3 1959.4 1959.5 1959.6 1959.7 1959.8
24.9 km
23.3 km
22.0 km
20.5 km
19.2 km
17.8 km
16.7 km
15.7 km
14.6 km
13.7 km
12.7 km
11.9 km
11.1 km
10.3 km
9.5 km
8.7 km
8.1 km
7.5 km
6.9 km
6.2 km
before
after
Simultaneously fit with the line at 1987.34 cm-1 using multiple rays across the field of view.
The line at 1987.34 cm-1 would have been more consistent with the other two strong lines without the change in broadening parameter.
Note: different # of data points averaged for the two lines for this altitude
ACE
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
1207 1207.1 1207.2 1207.3 1207.4 1207.5 1207.6
14.6 km
13.7 km
12.7 km
11.9 km
11.1 km
10.3 km
9.5 km
8.7 km
8.1 km
7.5 km
6.9 km
6.2 km
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
1207 1207.1 1207.2 1207.3 1207.4 1207.5 1207.6
14.6 km
13.7 km
12.7 km
11.9 km
11.1 km
10.3 km
9.5 km
8.7 km
8.1 km
7.5 km
6.9 km
6.2 km0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
1207 1207.1 1207.2 1207.3 1207.4 1207.5 1207.6
14.6 km
13.7 km
12.7 km
11.9 km
11.1 km
10.3 km
9.5 km
8.7 km
8.1 km
7.5 km
6.9 km
6.2 km
HITRAN: pbhw = 0.0814, strength = 1.4e-24
NEW: pbhw = 0.0986, strength = 2.83e-24 (+102%)
before
after
H2O
ACE
0
0.2
0.4
0.6
0.8
1
1.2
955 955.1 955.2 955.3 955.4 955.5
14.6 km
13.7 km
12.7 km
11.9 km
11.1 km
10.3 km
9.5 km
8.7 km
8.1 km
7.5 km
6.9 km
6.2 km
HITRAN: pbhw = 0.0702, strength = 2.98e-24
NEW: pbhw = 0.0877, strength = 4.09e-24 (+37%)
-0.07
-0.05
-0.03
-0.01
0.01
0.03
0.05
955 955.1 955.2 955.3 955.4 955.5
14.6 km
13.7 km
12.7 km
11.9 km
11.1 km
10.3 km
9.5 km
8.7 km
8.1 km
7.5 km
6.9 km
6.2 km
-0.07
-0.05
-0.03
-0.01
0.01
0.03
0.05
955 955.1 955.2 955.3 955.4 955.5
14.6 km
13.7 km
12.7 km
11.9 km
11.1 km
10.3 km
9.5 km
8.7 km
8.1 km
7.5 km
6.9 km
6.2 km
ACE
Big changes in the weakest Big changes in the weakest HH22O linesO lines
Line (cm-1)
HITRAN pbhw
NEW pbhw
HITRAN strength
NEW strength
strength change
HITRAN pshift
NEW pshift
1959.63
.0845 .1007 6.21e-24
6.71e-24
+8% .00151 -.0188
955.25 .0702 .0877 2.98e-24
4.09e-24
+37%
1207.27
.0814 .0986 1.40e-24
2.83e-24
+102%
941.02 .0732 .0872 1.88e-24
2.75e-24
+46%
944.86 .0419 .0469 1.26e-24
1.87e-24
+48%
944.95 .0358 .0485 4.24e-25
7.43e-25
+75%
955.69 .0407 .0496 1.63e-24
2.32e-24
+42% .00006 -.00318
1214.96
.0768 .0929 7.75e-24
8.37e-24
+8%
2732.49
.0651 .0821 9.84e-25
1.70e-24
+73%
2912.38
.0660 .0787 5.93e-25
1.12e-24
+89%
2912.47
.0688 .0763 3.58e-24
4.32e-24
+21%
ACEHH22O summaryO summary
Huge changes in intensities for the Huge changes in intensities for the lines used to retrieve Hlines used to retrieve H22O at lowest O at lowest altitudes.altitudes.
Generate parameters from 95 tropical Generate parameters from 95 tropical occultations (instead of just 4).occultations (instead of just 4).
HH22O is an interference for a lot of other O is an interference for a lot of other molecules in the troposphere. Try to molecules in the troposphere. Try to improve the spectroscopic parameters improve the spectroscopic parameters for those Hfor those H22O lines as well.O lines as well.
ACECHCH44 line mixing? line mixing?
0
0.2
0.4
0.6
0.8
1
1.2
2914.15 2914.35 2914.55 2914.75 2914.95 2915.15
Wavenumber (cm-1)
Tra
nsm
itta
nce
19.5 km
18.2 km
17.1 km
16.0 km
14.9 km
14.0 km
13.3 km
12.5 km
11.7 km
10.6 km
9.7 km
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
0.05
2914.15 2914.35 2914.55 2914.75 2914.95 2915.15
Wavenumber (cm-1)
Res
idu
als
(Ob
s -
Cal
c)
19.5 km
18.2 km
17.1 km
16.0 km
14.9 km
14.0 km
13.3 km
12.5 km
11.7 km
10.6 km
9.7 km
Red curve is the contribution in the window from NO2. Line mixing in weak CH4 lines could yield problems with low altitude NO2, HCl, and CH4, plus weak absorbers H2CO, CH3Cl, acetone,….
ACE
CC22HH66
CH3Cl, average of 20 tropical occultations
0
5
10
15
20
25
30
35
0.0 0.2 0.4 0.6 0.8 1.0
Volume mixing ratio (ppbv)
Alt
itu
de
(km
)
With C2H6Without C2H6
Residuals in CH3Cl window (near 2967 cm-1) without C2H6.
Red curve is the C2H6 contribution in this window, calculated from Geoff Toon’s pseudolines. No C2H6 data near 2967 cm-1 for HITRAN (including C2H6 update).
Lack of C2H6 in calculated spectrum yields overestimate of CH3Cl
ACECFC-12CFC-12
?
Near 922 cm-1 Near 1161 cm-1
ACE
Lineshape problem in Lineshape problem in CO?CO?
CO lines
ACEHCl calibration?HCl calibration?
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
0.05
2980.75 2980.85 2980.95 2981.05 2981.15 2981.25
Wavenumber (cm-1)
Res
idu
als
(Ob
s -
Cal
c)
49.3 km
46.8 km
44.2 km
41.7 km
39.3 km
36.9 km
34.8 km
32.7 km
30.8 km
28.9 km
27.2 km
25.6 km
24.1 km
19.5 km
18.2 km
0
0.2
0.4
0.6
0.8
1
1.2
2980.75 2980.85 2980.95 2981.05 2981.15 2981.25
Wavenumber (cm-1)
Tra
nsm
itta
nce
49.3 km
46.8 km
44.2 km
41.7 km
39.3 km
36.9 km
34.8 km
32.7 km
30.8 km
28.9 km
27.2 km
25.6 km
24.1 km
19.5 km
18.2 km
-0.04
-0.03
-0.02
-0.01
0
0.01
0.02
0.03
0.04
0.05
2980.75 2980.85 2980.95 2981.05 2981.15 2981.25
Wavenumber (cm-1)
Res
idu
als
(Ob
s -
Cal
c)
49.3 km
46.8 km
44.2 km
41.7 km
39.3 km
36.9 km
34.8 km
32.7 km
30.8 km
28.9 km
27.2 km
25.6 km
24.1 km
19.5 km
18.2 km
HITRAN
HCl
Residuals with HCl line 2981.0017 2981.0001 cm-1
2703.0114 2703.0098 cm-1
2752.0364 2752.0346 cm-1
HCl problem or other molecules?
ACESummarySummary
HNOHNO33 problems. Internal consistency. problems. Internal consistency. Bad residuals degrading results for other Bad residuals degrading results for other molecules, preventing SOmolecules, preventing SO22 retrievals. retrievals.
HNOHNO33 pseudolines to allow SO pseudolines to allow SO22 retrieval? retrieval?