1 TCCON at Caltech, May 2008 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., ANTONY et al., SMITH et al., PREDOI-CROSS et al., TRAN et al. KASSI et al., GAO et al., LIU et al. O 2 : 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).

HITRAN 2008 METHANE: The Polyads  Global fit  new From Boudon et al. EGU μm 2.3 μm

HITRAN 2008 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) cm -1 Reduced energy (cm -1 ) vs J: Many new assignments found using cold (78 K) spectra. Modeling the line positions improved by factor of 10! Better predicted spectrum ←Pentad ← Octad Tetradecad Isocad →

HITRAN CH 4 Global modeling: 0–4800 cm -1 Albert et al. (almost submitted)

HITRAN 2008 Octad: measured line intensities top: Log of measured line intensities bottom: %(observed – calc) NEED: More and better measurements of weak lines (including 13 CH 4 )! Needed to obtain better modelling of line intensities

HITRAN CH 4 : cm -1 : formerly intractable Must assign and model 60 sub-vibrational bands from Kassi et al. accepted 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 cm -1 ▪ Frankenberg et al. FTS spectra 5998 – 6130 cm -1 (with N 2 - pressure broadening) Best hope for HITRAN 2008: USE EMPIRICAL LINELISTS? Tetradecad 2ν 3 good for ground-based retrievals ↔ H 2 O ← 4800 cm HITRAN 1992: Margolis 1988, 1990: cm -1 : 2684 stronger lines with many empirical lower states HITRAN 2004: Brown 2005: line positions, weaker intensities: for , 6184 – 9200 cm -1 (empirical E″ lost in reformating)

HITRAN 2008 CH 4 : 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). Q Need theoretical modeling to understand assignments!

HITRAN 2008 Status of 12 CH 4 Parameters Polyad / Spectral regionLine positionsLine intensitiesLine shape 1 – Ground state 0–200 cm -1 (> 50  m) Complete analysis, J ≤ 24 Few measurements to confirm analysis 2 – Dyad 1000–1800 cm -1 (5.6–10.0  m) Complete analysis, J ≤ 23 Complete analysis with 9 hot bands Old & New measurements 3 – Pentad 2200–3300 cm -1 (3.0–4.6  m) Complete analysis, J ≤ 18 Cold band ok; few hot band intensities Old meas. & New theory ν 3 only 4 – Octad 3700–4800 cm -1 (2.0–2.7  m) Good analysis, Cold bands J ≤ 17 ~ Better analysis, cold bands only ~ 1100 air- widths and shifts 5 – Tetradecad 5400–6300 cm -1 (1.6–1.9  m) Incomplete analysis, J ≤ 10 Partial analysis, cold bands only A few hundred new measurements 6 – Icosad 6600–7700 cm -1 partial analysis of 1 band? measurements but No prediction Upper polyads > 7800 cm -1 (< 1.28  m) ??

HITRAN 2008 Methane Work in Progress

HITRAN 2008 New Pressure Broadening for Methane 7 μm: measured widths, shifts, temp. depend., Line mixing Benner, Devi, Predoi-Cross, Smith….. - in prep. 3.3 μm ν 3 : 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 N 2 -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) v 4 Tran et al. JQSRT 2006 v 4 and v 3 Predoi-Cross et al. JMS 2007 v 2 +v 3 Mondelain et al. 2007, 2008 P9 of v 3 : temp dependence= 1.2 – 1.5

HITRAN 2008 Line mixing calculations for methane

HITRAN 2008 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 Narrowing β

HITRAN 2008 Methane for HITRAN 2008 under construction REGION (cm -1 ) NEW POSITIONS AND INTENSITIES : 12 CH 4 global fit – (nothing new for 13 CH 4 ) : CH 3 D (and maybe at 6600 cm -1 ) : lots of work in progress, but not ready NEW Voigt Broadening Parameters Apply ν 3 calculated widths and temp. dep Then replace with available measurements New N 2 -broadening at 1.66 um + ??? (3000 out of transitions) Estimate shifts and use limited measurements Line mixing: tbd ??

HITRAN 2008 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 Revised Collision Induced Absorption (CIA) But still a problem: Can’t retrieve right O 2 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)

HITRAN 2008

Oxygen A - Band at 760 nm using NIST CRDS (Joe Hodges) Line intensities and positions of P branch retrieved with Galatry profile: 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 cm -1 of NIST calibrated measurements. NIST/Caltech/JPL: Robichaud et al Intensities measured with NIST samples Line positions calibrated with atomic K transitions With accuracies better than cm MHz = cm -1 Ratio of Ints. Others/HITRAN

HITRAN 2008 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 Air-widths: refit to Yang empirical eq.

HITRAN 2008 O 2 Pressure shifts: uncertain because of calibration of wavenumber scale and/or line shape choices? Alternative to Voigt profiles Dicke narrowing? Speed dependence? Need consensus about best line shape! Ciurylo and Szudy, JQSRT 1997 From Predoi-Cross in press

HITRAN 2008 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 16 O 18 O and 16 O 17 O will be provided to HITRAN with broadening from the main isotope applied.

HITRAN 2008 Oxygen A - Band at 760 nm Weak line mixing: first order coefficients Left: measured with speed dependence Voigt vs Voigt Predoi- Cross et al. in press Tran and Hartmann in press Measured using Speed depend. Voigt or Voigt R & P similar to Q at each m Black: ECS calculated mixing Gray: Measured Predoi-Cross et al.

HITRAN 2008 Oxygen A - Band at 760 nm New 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

HITRAN 2008 O 2 : test with synthetic spectra at infinite resolution 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? Black: synthetic spectrum calculated by Pine using Tran et al code Line mixing is full “w” matrix. Pressure = 1 atm of air; path = 1 km

HITRAN 2008 O 2 A-band for HITRAN 2008: Positions: use Robichaud et al. (NIST-CRDS): isotopes too Intensities: scale using Robichaud et 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 or Predoi-Cross et al. 2008) Temp. dependence of widths, shifts, mixing, narrowing: ??? Line mixing ???? Tran and Hartmann 2008 or Predoi-Cross et al CIA: Trans and Hartmann (2008)