new line parameters for near ir methane and the oxygen a band presented by linda r brown jpl l.
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New Line Parameters for Near-IR Methane and the Oxygen A-Band presented by Linda R. Brown (JPL). World-wide Effort Belgium, Canada, France, Germany, Netherlands, Russia, Switzerland, United States CH 4 : BOUDON et al., NIKITIN et al. , QUACK et al., FRANKENBERG et al.,

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new line parameters for near ir methane and the oxygen a band presented by linda r brown jpl

New Line Parameters for Near-IR Methane and the Oxygen A-Bandpresented byLinda R. Brown (JPL)

World-wide Effort

Belgium, Canada, France, Germany, Netherlands,

Russia, Switzerland, United States

CH4:BOUDON et al., NIKITIN et al. , QUACK et al., FRANKENBERG et al.,

ANTONY et al., SMITH et al., PREDOI-CROSS et al., TRAN et al.

KASSI et al., GAO et al., LIU et al.

O2: TRAN et al., PREDOI-CROSS et al., ROBICHAUD et al., BROWN et al.

JPL: Part of the research described in this paper was performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA).

methane the polyads

Global fit

METHANE: The Polyads

1.7 μm

2.3 μm

new

From Boudon et al. EGU 2008

much improved analyses using really cold data
Much improved analyses using really cold data

►Near-IR spectra at 78 K permitted more Octad bands to be assigned.

►Higher order terms were added to Hamiltonian models for Global fit.

Doppler-limited spectra from a Bruker FTS in Zurich (M. Quack) 2700 - 8000 cm-1

Reduced energy (cm-1) vs J: Many new assignments found usingcold (78 K) spectra.

←Pentad

← Octad

Modeling the line positions improved by factor of 10!

Better predictedspectrum

Tetradecad

Isocad →

12 ch 4 global modeling 0 4800 cm 1
12CH4 Global modeling: 0–4800 cm-1

Albert et al. (almost submitted)

octad measured line intensities
Octad: measured line intensities

Needed to obtain bettermodelling of line intensities

top:Log of measured line intensitiesbottom:%(observed – calc)

NEED: More and better measurements of weak lines (including 13CH4)!

12 ch 4 4800 6300 cm 1 formerly intractable must assign and model 60 sub vibrational bands
12CH4: 4800 - 6300 cm-1:formerly intractable Must assign and model 60 sub-vibrational bands

2ν3 good for ground-based retrievals

  • HITRAN 1992: Margolis 1988, 1990: 5500-6184 cm-1: 2684 stronger lines with many empirical lower states
  • HITRAN 2004: Brown 2005: line positions, weaker intensities: for 4800-5500, 6184 – 9200 cm-1

(empirical E″ lostin reformating)

H2O ←

Tetradecad

4800 cm-1 6400

NEW Hope: FTS and CRDS spectra at 78 Kelvin.

▪Quack et al.

FTS spectra at 78 K : line positions & assignments

▪ Liu et al., Gao et al., Kassi et al.

CRDS: Intensities and empirical lower state energy 5852-6181 cm-1

▪Frankenberg et al.

FTS spectra 5998 – 6130 cm-1 (with N2- pressure broadening)

Best hope for HITRAN 2008: USE EMPIRICAL LINELISTS?

from Kassi et al. accepted

ch 4 6600 7700 cm 1 intractable region must assign and model 134 sub vibrational bands
CH4: 6600 - 7700 cm-1:~intractable region Must assign and model 134 sub-vibrational bands

Cold spectra:

hope to see new assignments by inspection!

or

Solve for empirical lower state energies using line intensities measured

at different temperatures

Kassi, Gao, Romanini and Campargue (in press).

3 2 1

Q

Need theoretical modeling to understand assignments!

new pressure broadening for methane
New Pressure Broadeningfor Methane

• 7 μm: measured widths, shifts, temp. depend., Line mixing Benner, Devi, Predoi-Cross, Smith….. - in prep.

• 3.3 μm ν3: theoretical calculation of widths, shifts and temperature dependence of widths for A and F

Antony et al. J. Mol. Spectrosc. in press

• 1.6 μm N2-widths and shifts of stronger lines above 5998 cm-1

Frankenberg et al. Atmos. Chem. Phys.-accepted.

• Line mixing: weak but needed in atmospheric retrievals:

Smith et al. (poster) v4

Tran et al. JQSRT 2006 v4 and v3

Predoi-Cross et al. JMS 2007 v2+v3

Mondelain et al. 2007, 2008 P9 of v3 : temp dependence= 1.2 – 1.5

line mixing required
LINE MIXING + REQUIRED

Mondelain et al. 2008:Atmospheric spectra

►Measured and calculated transmissions

at a tangent height of ~ 18 km.

►Fitting residuals (observed–calculated)

are (from top to bottom)

1) Voigt model with HITRAN values

2) Voigt model with their new line mixing

3) Voigt model with their new temperature

dependence exponent

4) a hard model without line mixing

(using their new values)

5) a hard model (Rautian) with line mixing and their new temperature dependence exponents.

Need Line mixing (Rosenkranz)ζ

and Dicke Narrowingβ

methane for hitran 2008 under construction
Methane for HITRAN 2008under construction

REGION (cm-1)NEW POSITIONS AND INTENSITIES

  • 0 - 4800: 12CH4 global fit
          • (nothing new for 13CH4)
  • 3300- 3700: CH3D (and maybe at 6600 cm-1)
  • 4800- 7700: lots of work in progress, but not ready
  • NEW Voigt Broadening Parameters

Apply ν3 calculated widths and temp. dep

Then replacewith available measurements

New N2-broadening at 1.66 um + ???

(3000 out of 250000 transitions)

  • Estimate shifts and use limited measurements
  • Line mixing: tbd ??
oxygen a band at 760 nm 13122 cm 1
Oxygen A - Band at 760 nm (13122 cm-1)
  • New effort by Tran & Hartmann:
  • Still Ordinary Voigt
  • Full W-matrix Line mixing but with

different line broadening parameters

  • used empirical expression for widths from Yang et al. 2005
  • Revised Collision Induced Absorption (CIA)
  • But still a problem:

Can’t retrieve right O2 abundance

inaccurate line parameters?

missing isotopes?

wrong line shapes?

(a)Ground-based Atmospheric spectra

Park Falls FTS (P. Wennberg)

Voigt only :

LINE MIXING REQUIRED!!!

(b)Tran et al. JGR-Atmos 2006

(c)New: Tran and Hartmann

( in press)

slide16
Oxygen A - Band at 760 nm using NIST CRDS (Joe Hodges)Line intensities and positions of P branch retrieved with Galatry profile:

Line positions calibrated with atomic K transitions

With accuracies better than 0.00005 cm-1

NIST/Caltech/JPL:Robichaud et al. 2008

Intensities measured with NIST samples

Ratio of Ints. Others/HITRAN

30 MHz = 0.001 cm-1

Should lower calculated intensities:

Compared to HITRAN 2004:

NIST CRDS is-0.8%

Average of 9 studies is-1.3%

(how much of this difference is due to

the different line shapes used?)

HITRAN line positions (B&P) are within 0.0007 cm-1 of NIST calibrated measurements.

oxygen a band at 760 nm air widths
Oxygen A - Band at 760 nm Air-widths

Different line shapes produce different values of air-widths:

Red: line mixing with speed dependence

Green: Voigt with Dicke Narrowing &

No line mixing (NIST CRDS)

Blue: Voigt with line mixing

Which set gives the best accuracies?

Above: Robichaud et al. 2008

Air-widths: refit to Yang empirical eq.

o 2 pressure shifts uncertain because of calibration of wavenumber scale and or line shape choices
O2 Pressure shifts:uncertain because of calibration of wavenumber scale and/or line shape choices?

Ciurylo and Szudy, JQSRT 1997

Alternative to Voigt profiles

Dicke narrowing?

Speed dependence?

Need consensus about best line shape!

From Predoi-Cross in press

isotopologues of the oxygen a band at 760 nm
Isotopologues of the Oxygen A - Band at 760 nm

Work in progress at NIST/Caltech (Robichaud et al. in prep.)

Isotopologues measured with enriched samples using CRDS

Positions, many intensities and some “self-broadened” line widths

New results for 16O18O and 16O17O will be provided to HITRAN with broadening from the main isotope applied.

oxygen a band at 760 nm weak line mixing first order coefficients
Oxygen A - Band at 760 nm Weak line mixing: first order coefficients

Left: measured with

speed dependence Voigt vs Voigt

Black: ECS calculated mixing

Gray: Measured Predoi-Cross et al.

Measured using

Speed depend.

Voigt

or Voigt

R & P similar to Q at each m

Predoi-Cross et al. in press

Tran and Hartmann in press

oxygen a band at 760 nm new effort with kitt peak fts lab spectra
Oxygen A - Band at 760 nmNew effort with Kitt Peak FTS lab spectra:

Combine Kitt Peak FTS lab data from Brown and Plymate (2000) with new higher pressure scans up to ~ 3 atm.

Brown, Pine, Miller

Best fit using

Rautian (narrowing) with

weak line mixing

o 2 test with synthetic spectra at infinite resolution
O2: test with synthetic spectra at infinite resolution

Black: synthetic spectrum calculated by Pine using Tran et al. 2006 code Line mixing is full “w” matrix.

Pressure = 1 atm of air; path = 1 km

Lower panels are differences between top and other calculated spectra (offset by successive increments of - 0.2) --------------------------------------------Green: shows Pine’s software computes the same spectrum as Tran’s code

Rust: only Voigt used.

Teal: difference with W-matrix and Rosenkranz line mixing

Purple: Rosenkranz line mixing adjusted to match the top spectra

Brown: 4 other synthetic spectra o were computed at different gas conditions and fitted as test data using multi-spectrum fitting.

Didn’t quite match R branch band head.

Voigt inadequate!

Rosenkranz: good enough for atmosphere?

o 2 a band for hitran 2008
O2 A-band for HITRAN 2008:
  • Positions: use Robichaud et al. (NIST-CRDS): isotopes too
  • Intensities: scaleusing Robichaudet al. or average of many: ±0.5%
  • Widths: empirical expression Robichaud or Predoi-Cross model
  • Shifts: ???????? Dependences on line shape model
  • Dicke narrowing (Robichaud et al. 2008 or Predoi-Cross et al. 2008)
  • Temp. dependence of widths, shifts, mixing, narrowing: ???
  • Line mixing ????

Tran and Hartmann 2008 or Predoi-Cross et al. 2008

  • CIA: Trans and Hartmann (2008)