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

HITRAN meetingHITRAN meetingJune, 2008June, 2008

ACE

Atmospheric Chemistry Atmospheric Chemistry ExperimentExperiment

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

UV / Visible spectrometer (MAESTRO) 0.285 UV / Visible spectrometer (MAESTRO) 0.285 to 1.03 microns, resolution ~1-2 nmto 1.03 microns, resolution ~1-2 nm

SuntrackerSuntracker StartrackerStartracker

ACE

ACE-FTS (ABB-ACE-FTS (ABB-Bomem)Bomem)

Interferometer-side Input optics-side

ACESNRSNR

Courtesy of Ryan Hughes

ACE

COCO22 microwindows microwindows

CO2 microwindow evaluation

-0.0001

0

0.0001

0.0002

0.0003

0.0004

0.0005

0 20 40 60 80 100 120

Altitude (km)

CO

2 V

MR

(p

pv)

Discarded 14 CO2 microwindows.

ACE

Scale COScale CO22 microwindows?microwindows?

0.0003

0.00032

0.00034

0.00036

0.00038

0.0004

0.00042

10 20 30 40 50

Altitude (km)

CO

2 V

MR

(p

pv)

0.0003

0.00032

0.00034

0.00036

0.00038

0.0004

0.00042

10 20 30 40 50

Altitude (km)

CO

2 V

MR

(p

pv)

0.950.960.970.980.99

11.011.021.03

0 10 20 30 40 50 60

microwindow #

scal

ing

fac

tor

0.950.960.970.980.99

11.011.021.03

900 1400 1900 2400

Wavenumber (cm-1)

scal

ing

fac

tor

HITRAN Scaled intensitiesRetrievals from a single microwindow, average of 95 occultations

Sticking with HITRAN.

ACE

HNOHNO33 Internal Internal ConsistencyConsistency

Reduce all HNO3 line intensities in the 1700 cm-1 region by 8.5% for version 3.0 processing.

Average of 95 tropical occultations

0

10

20

30

40

50

60

70

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5

HNO3 VMR (ppbv)

Alt

itu

de

(km

)

900 cm-11700 cm-1

From November 2007June 2008, verifying that we used the updated HNO3 parameters

ACECFCF44 residuals residuals

Large residuals from HNO3. Similar issues with ClONO2.

HNOHNO33 Spectroscopy EvaluationSpectroscopy Evaluation

Geoffrey ToonJet Propulsion Laboratory

California Institute of Technology

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?

HNOHNO33 ground-state ground-state bandsbands

458.2 nu9 580.3 nu7 646.8 nu6 763.2 nu8 879.1 nu5 896.4 2nu9 1031.5 nu7 + nu9 1100.4 nu6 + nu9 1166.3 2nu7 1205.0 nu8 + nu9 1224.6 nu6 + nu7 1288.0 2nu6 1303.2 nu4 1326.2 nu3 1334.6 nu5 + nu9 1340.8 nu7 + nu8 1407.2 nu6 + nu8 1456.5 nu5 + nu7

2467.9 nu2 + nu8 2583.5 nu2 + nu5 2601.2 2nu4 2624.1 nu3 + nu4 2645.1 2nu3 3006.8 nu2 + nu4 3029.7 nu2 + nu3 3412.4 2nu2 3551.7 nu1 4006.9 nu1 + nu9 4123.7 nu1 + nu7 4190.1 nu1 + nu6 4306.3 nu1 + nu8 4421.9 nu1 + nu5 4845.2 nu1 + nu4 4868.1 nu1 + nu3 5250.8 nu1 + nu2 7089.2 2nu1

1515.8 nu5 + nu6 1533.3 2nu8 1639.0 nu5 + nu8 1709.6 nu2 1756.7 2nu5 1757.9 nu4 + nu9 1789.2 nu3 + nu9 1879.7 nu4 + nu7 1902.7 nu3 + nu7 1918.1 nu4 + nu6 1949.1 nu3 + nu6 2061.3 nu4 + nu8 2092.2 nu3 + nu8 2140.5 nu2 + nu9 2177.9 nu4 + nu5 2200.9 nu3 + nu5 2285.3 nu2 + nu7 2351.7 nu2 + nu6

Bold indicates present in July 2006 HITRAN update

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?

10

15

20

25

30

0 10 20 30 40H2O VMR (ppmv)

Alt

itu

de

(k

m)

Broadening changed

HITRAN

101214

1618202224

262830

0.96 0.98 1.00 1.02 1.04 1.06

VMR(changed)/VMR(HITRAN)

Alt

itu

de

(k

m)

Change intensity by ~3%? Still debating this one.

ACE

HITRAN: pbhw = 0.0845, strength = 6.21e-24, pshift = 0.00151

NEW: pbhw = 0.1004, strength = 6.71e-24 (+8%), pshift = -0.0190

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.

ACEInternal consistency?Internal consistency?

Average of 95 tropical occultations

10

15

20

25

30

35

40

0 0.00001 0.00002 0.00003 0.00004 0.00005 0.00006H2O VMR (ppv)

Alt

itu

de

(km

)

1987.34 cm-1

1885.3 cm-11198.18 cm-1

1959.52 cm-1 (before)1959.52 cm-1 (after)

Average of 95 tropical occultations (zoom)

10

15

20

25

30

35

40

0 0.000002 0.000004 0.000006 0.000008 0.00001

H2O VMR (ppv)

Alt

itu

de

(km

)1987.34 cm-1

1885.3 cm-11198.18 cm-1

1959.52 cm-1 (before)1959.52 cm-1 (after)

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?

HH22O weak lines exhibit poor internal O weak lines exhibit poor internal consistency, causes accuracy problems consistency, causes accuracy problems with ACE tropospheric Hwith ACE tropospheric H22O retrievals.O retrievals.

Fix CFix C22HH66, especially missing data regions., especially missing data regions.

CHCH44 line mixing parameters for weak lines. line mixing parameters for weak lines.