1. IRWG / TCCON Meeting, Jeju, May 30 – June 3, 2015 The use of the portable EM27/SUN FTIR spectrometer as a travel standard for the TCCON Mahesh Kumar Sha, Martine De Mazière Royal Belgian Institute for Space Aeronomy Jean-Marc Metzger, Jean-Pierre Cammas Université de la Réunion Matthias Frey, Matthäus Kiel, Frank Hase Karlsruhe Institute of Technology

2. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- TCCON site at Ile de La Réunion (21° S, 55° E) Location: University of St. Denis (-20.901° N, 55.485° E, 85 m.a.s.l) A unique atmospheric observatory situated in the Indian Ocean in the Souther Hemisphere, provides the background state as well as the influence of biomass burning in Madagascar, South Africa and South America Instrument characteristics: Bruker IFS 125HR, CaF 2 Beamsplitter and optics, home-built sun- tracker and electronics Detectors: InGaAs and Si Time series: Site operational since September 2011 Operation mode: Automatic with remote monitoring and control possibilities TCCON site at Ile de la Réunion FTIR spectrometer – Bruker IFS 125HR St. Denis

3. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- St. Denis TCCON time series of GHGs (XCO 2, XCH 4, XCO) Time series of few selected GHG Visualize our data here: http://infrared- data.aeronomie.be/ Absolute calibration not performed yet  certification pending

4. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- Remote location, island, difficult terrain Google Earth

5. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- Calibration using in-situ techniques BRAIN-be pioneering project (UAV_REUNION) – In-situ calibration of TCCON measurements – Deployment of an AirCore using stratospheric balloons, release at ~30 km – Collect a continuous sample of the atmosphere on descent – Landing in pre-determined area using computer – guided parafoil – Analysis of the atmospheric sample using a Picarro greenhouse gas analyzer Test at Sodankylä TCCON site in Finland – balloon-borne aircore coupled to a steerable para-foil landing system Test in Sodankylä site in June 2014 – not successful – balloon-borne aircore coupled to a steerable gliding wing system Test in Sodankylä site in June 2015 – not successful Partners: Huilin Chen (Rijksuniversiteit Groningen), Reev River Aerospace (Galati, Romania), at Sodankylä- support from Rigel Kivi, Pauli Heikkinen

6. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- Calibration using remote sensing techniques The EM27/SUN developed by KIT in cooperation with Bruker (Gisi et al., 2012) is selected as the reference remote sensing instrument Currently the best tested portable light weight (~25 kg) spectrometer  ideal for this study The core of the spectrometer is a RockSolid TM pendulum interferometer which guaranties robustness It has a MOPD of 0.9 cm; resolution: 0.5 cm-1; measures double sided interferogram using an InGaAs detector with a spectral range of 5000 – 11000 cm-1 It has a Field-of-view of 2.36 mrad and uses standard non freq.-stabilized HeNe reference laser This instrument has shown superb performance in the past producing results which were comparable with an on-site TCCON instrument  Side-by-side remote sensing measurements using a high precision portable FTIR (EM27/SUN) at our site Ile de la Réunion  Calibration campaign funded by ACTRIS-2 TransNational Access grant Zarges box with the EM27/SUN packed inside EM27/SUN and the data acquisition computer

7. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- EM27/SUN calibration at KIT EM27/SUN – resolution 0.5 cm-1 → measures the total column concentration of O2, CO2, CH4 and H2O in NIR TCCON – resolution 0.02 cm-1 → measures the total column concentration of O2, CO2, CH4, H2O, … in NIR

8. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- Calibration using remote sensing techniques Calibration factor of the spectrometer # 10 w.r.t. the spectrometer # 1 XCO2: 0.9995 and XCH4: 0.9993 Calibration factor of the spectrometer # 10 w.r.t. the IFS 125HR XCO2: 0.9928 (TCCON  0.9898) and XCH4: 0.9937 (TCCON  0.9765) EM27/SUN spectrometer operated at St. Denis next to the TCCON spectrometer Bruker IFS 125HR spectrometer at St. Denis

9. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- Comparison results I Black – TCCON (standard) Red – EM27/SUN (standard) EM27/SUN data scaled with the calibration factor estimated at KIT 2015-10-21: Measurement error for EM27/SUN, records only ifg and no spectrum

10. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- Comparison results II Black – TCCON (standard) Blue – EM27/SUN (standard) Red – EM27/SUN analysis with TCCON retrieved a priori

11. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- Comparison results III Black – EM27/SUN (standard) resolution 0.5 cm-1, processed with PROFFIT, WACCAM V6 a priori, ptn profile Red – TCCON low resolution 0.5 cm-1, processed with PROFFIT, WACCAM V6 a priori, ptn profile OCO-2 targetting

12. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- Problem with interferogram / spectrum of an EM27/SUN Sometimes OPUS from the EM27/SUN spectrometer records only ifg’s and not ifg + spectrum Issue with MOPD? Analyze the data with reduced resolution  confirm ifg to be symmetric around ZPD This solution is not implemented yet in CALPY/PROFFIT (data analysis with only fixed resolution possible) Not a big problem at the moment. It occurred only two times un-noticed. If it happens to you, restart the spectrometer. Perhaps a reset of the laser is needed to record the measurements with a resolution of 0.5 cm-1 Measurement before campaign in KarlsruheFirst day of measurement during campaign in La Réunion

13. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- Outlook: Reunion TCCON data calibration Plans to repeat the measurements again (in a few months) during a different season – checking the consistency of the calibration factors over a longer period of time – perform measurements during the wet-season to check the influence of water on the retrievals KIT is willing to provide a calibrated EM27/SUN temporarily for x-calibration of additional TCCON sites (so far demonstrated for Paris, Sodankylä, Lauder & La Réunion) Intercomparison of several portable FTIR spectrometers in Sodankylä next year (March – October 2017) – FRM4GHG campaign – check the quality of the portable spectrometers w.r.t. the TCCON site – check the seasonal variability of the calibration parameters if any – determine the best instrument / instruments for this kind of study, especially needed where the standard method of calibration is not possible (e.g. remote location or city location)

14. BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPATIALE DE BELGIQUE BELGIAN INSTITUTE OF SPACE AERONOMY BELGISCH INSTITUUT VOOR RUIMTE-AERONOMIE INSTITUT D’AERONOMIE SPAT- Thank you for your attention