1. KIT – University of the State of Baden-Wuerttemberg and National Research Center of the Helmholtz Association Institute for Meteorology and Climate Research IMK ASF www.kit.edu Addition of a second channel for XCO observations to a portable FTIR spectrometer for greenhouse gas measurements Presenter: M. Frey, KIT, IMK-ASF

2. IMK-ASF 2 Outline Introduction / recent COCCON activities Technical setup prototype Atmospheric measurements Summary M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

3. IMK-ASF 3 COCCON service Collaborative Carbon Column Observing Network Network of EM27/SUN spectrometers Check of new instruments at KIT  Alignment check  ILS measurements  Solar measurements with co-located TCCON instrument (full res & low res) Loan of instruments possible for campaign deployment Retrieval algorithm PROFFIT available (training at KIT possible) Central processing of EM27/SUN spectra in planning M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

4. IMK-ASF 4 Recent COCCON activities Campaigns in Paris, Boulder and Tokyo  Talk “Detection of CO 2 and CH 4 megacity emissions using an array of portable FTIR spectrometers” Deployment in remote areas  Gobabeb, Namibia  Gadanki, India (Gadhavi et al.)  Antarctica (short term only) (Pollard et al.)  La Reunion, France (short term only)  Talk by Mahesh “The use of the portable EM27/SUN FTIR spectrometer as a travel standard for the TCCON” New channel for XCO measurements (Hase et al, AMT 2016)  First deployment in recent Indianapolis campaign (Wofsy et al.) M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

5. IMK-ASF 5 Technical setup M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer… F. Hase, M. Frey, M. Kiel, T. Blumenstock, R. Harig, A. Keens, and J. Orphal, „Addition of a channel for XCO observations to a portable FTIR spectrometer for greenhouse gas measurements“ AMT, 2016

6. IMK-ASF 6 Technical setup M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

7. IMK-ASF 7 Solar spectra characteristics Second channel covers 4000 – 5500 cm -1 wavenumber region Transition region coincides with strong water vapour absorption lines Signal to noise ratio 13000 for primary channel, 20000 for secondary channel 4210 – 4320 cm -1 spectral window used for CO analysis Fit residuals due to inadequacies in spectroscopic parameters M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

8. IMK-ASF 8 XCO measurements prototype and reference TCCON spectrometer M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

9. IMK-ASF 9 XCO measurements prototype and reference TCCON spectrometer M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

10. IMK-ASF 10 XCO intraday variability comparison M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

11. IMK-ASF 11 Summary Extension of a existing EM27/SUN spectrometer with a secondary channel for XCO observations Good agreement with TCCON measurements Intraday variability well captured Secondary channel will be a valuable extension for campaigns focussing on source apportionment M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

12. IMK-ASF 12 M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

13. IMK-ASF 13 Design considerations Different approaches possible: Replacement of standard detector element with extended InGaAs diode Pro: straightforward approach Contra: observed dependence of XCO 2 and XCH 4 on overall signal level due to increased bandwidth Additional detector element Again, different approaches possible Sandwich detector Alternating observations with different detectors Distribution of optical beam for feeding two detector elements simultaneously M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

14. IMK-ASF 14 Oxygen column measurements prototype and reference EM27/SUN M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…

15. IMK-ASF 15 Methane column measurements primary and secondary channel M. Frey, Addition of a second channel for XCO observations to a portable FTIR spectrometer…