1. THE ATMOSPHERIC CHEMISTRY EXPERIMENT (ACE): CO, CH4 AND N2O ISOTOPOLOGUES
Peter Bernath1,2, Eric Buzan1, Chris Beale1, Mahdi Yousefi1 and Chris Boone2
1Old Dominion University, Norfolk, VA
2University of Waterloo, Waterloo, ON

2. Satellite Remote Sensing Special Issue (JQSRT)
19 papers in total including a substantial number on spectroscopy;
HITRAN Special Issue will be open for submissions from Oct. 1, 2016 to Jan. 15, 2017
The Reference Forward Model (RFM)
Anu Dudhia
OH Meinel band quenching coefficients derived from satellite observations
Patrick Sheese
LEVEL: A Computer Program for Solving the Radial Schroedinger Equation for Bound and Quasibound Levels
Robert Le Roy
Tropospheric Emissions: Monitoring of Pollution (TEMPO)
Peter Zoogman
Global climatology based on the ACE-FTS version 3.5 dataset: Addition of mesospheric levels and carbon-containing species in the UTLS
Kaley Walker
New and improved infrared absorption cross sections and ACE-FTS retrievals of carbon tetrachloride (CCl4)
Jeremy Harrison
Optimized approach to retrieve information on atmospheric carbonyl sulfide (OCS) above the Jungfraujoch station and change in its abundance since 1995
Bernard Lejeune
Retrieval of HCFC-142b (CH3CClF2) from ground-based high-resolution infrared solar spectra: atmospheric increase since 1989 and comparison with surface and satellite measurements
Manu Mahieu
ACE-FTS ozone, water vapour, nitrous oxide, nitric acid, and carbon monoxide profile intercomparisons with MIPAS and MLS
The Atmospheric Chemistry Experiment (ACE)
Peter Bernath
PGOPHER: A Program for Simulating Rotational, Vibrational and Electronic Spectra.
Colin Western
Fast radiative transfer using monochromatic look-up tables
Robert Vincent
dParFit: A Computer Program for Fitting Diatomic Molecule Spectral Data to Parameterized Level Energy Expressions
Robert Le Roy
A Computer Program to Fit Pointwise Potentials to Selected Analytic Function
Multispectrum analysis of the Oxygen A-band
Brian Drouin
A Computer Program Implementing the First-Order RKR Method for Determining Diatomic Molecule Potential Energy Functions
Spectroscopic line parameters of 12CH4 for atmospheric composition retrievals in the cm^-1 region
Robab Hashemi
WINDII on UARS in the context of SCISAT and Odin
Gordon Shepherd
A Computer Program to Fit Diatomic Molecule Spectral Data to Potential Energy Functions
Temperature-dependent absorption cross-sections of 2,2,3,3,3-pentafluoropropanol
Paul Godin

3. MOLLIST Website

4. ACE Satellite (Limb View)
Bernath et al., GRL, 32, L15S01 (2005)

5. ACE-FTS Version 3.5 Species
Tracers: H2O, O3, N2O, NO, NO2, HNO3, N2O5, H2O2, HO2NO2, N2
Halogen-containing gases: HCl, HF, ClONO2, CFC-11, CFC-12, CFC-113, COF2, COCl2, COFCl, CF4, SF6, CH3Cl, CCl4, HCFC-22, HCFC-141b, HCFC-142b
Carbon-containing gases: CO, CH4, CH3OH, H2CO, HCOOH, C2H2, C2H4, C2H6, OCS, HCN as well as pressure and temperature from CO2 lines
Isotopologues: H218O, H217O, HDO, O13CO, OC18O, OC17O, O13C18O, 18OO2, O18OO, O17OO, N15NO, 15NNO, N218O, N217O, 13CO, C18O, C17O, 13CH4, CH3D, OC34S, O13CS
Research species: ClO, acetone, PAN, HFC-23, acetonitrile, etc.
Isotopic fractionation of CO, CH4 and N2O: Chris Beale, Eric Buzan and Mahdi Yousefi (Old Dominion University)

6. ACE
WACCM δD
CH4 is an important greenhouse gas; isotopologues give new information on atmospheric chemistry and dynamics
δ13C

7. 323, (2016)
ACE
WACCM

8. N2O Isotopologues
N2O is an important greenhouse gas with GWP of 300 (3rd in terms of radiative forcing after CO2 and CH4)
Most significant ozone-depleting substance not controlled by the Montreal Protocol
Inert in the troposphere but is photolyzed in the stratosphere and reacts with O(1D) to make NO
Main sources are from soil and oceans (byproduct of microbial nitrification and denitrification processes)
ACE-FTS discovered a new upper atmospheric source from energetic particle precipitation (N + NO2 and N2* + O2 reactions) Semeniuk et al & Sheese et al. 2016
ACE-FTS measures N2O, 15NNO, N15NO and NN18O
Isotopologues provide information on atmospheric chemistry and dynamics

9. ACE N2O spectra at 15.5 km tangent altitude, 2ν3 mode 2563 cm-1

10. Upper Atmospheric N2O Destruction
N2O + hν → N2 + O(1D) 90%
N2O + O(1D) → N2 + O %
N2O + O(1D) → 2NO %

11. Isotopologues: Isotopic Molecules
15Rref = (N2, air)
18Rref = (Vienna standard mean ocean water)
325 ppb
2013 IPCC report

12. Isotopic Fractionation (Blake et al. 2003)
Within the Born-Oppenheimer approximation, the potentials
are the same. Heavier isotopologue has a lower ZPE, narrower
wavefunction and a shorter r0 bond length for an anharmonic
potential; this leads to a change in the absorption cross section.

13. N2O Isotopic FractionationJ
14N15N16O fractionation observed and calculated
N2O + hν → N2 + O(1D)
εi = (σi/σ – 1) x 1000
T=284 K
T=233 K
d[N2O]/dt = - J[N2O]
J = ∫σφFdλ
σ, absorption cross section
φ=1, quantum efficiency
F, actinic flux
Schmidt et al. 2011

14. ACE N15NO and 15NNO δ-values
Older air over the poles shows more fractionation and an increase in the heavier isotopologues.

15. N2O Isotopologue Validation
Kaiser et al. 2006, ACP 6, 3535:
balloon data over France

16. Whole Atmosphere Climate Community Model (WACCM)
Atmosphere component of Community Earth System Model (CESM)
Simulates physics and chemistry for km
4x5 degree resolution for all ACE comparison runs
Each isotopologue treated as a separate species
13CO, 13CH4, CH3D, 15NNO, N15NO, NN18O added with lower boundary conditions; for CO fractionation reactions with OH and photochemistry included; for CH4 fractionation by reaction with OH, Cl and O(1D) added; for N2O fractionation by photolysis and O(1D) added (in progress)
LBC calculated by isotope ratios from Röckmann et al. (2011)
Chemical kinetics constants from JPL publication, 2010

17. N2O Isotopologue Modelling
Ishijima et al. 2015, ACPD 15, 19947
Model δ-values for 15NNO
Observed ACE δ-values for 15NNO
ACE Data
Model

18. 13