Meeting Summary:

Routine application of novel stable isotope spectroscopy instruments

December 12, 2010

University of California, Berkeley

• Presentations
• Continuous field observations of stable isotope abundance ("Getting the data") - Knohl, Sturm, Siegwolf, Zeeman ►pdf
  
• Measuring δ13C and δ18O of CO2 at Harvard Forest using a Quantum Cascade Laser  Spectrometer - Wehr, Munger, Nelson, McManus, Zahniser, Saleska ►pdf
• Daily work with stable isotope spectroscopy instruments (and the things that DO not end up in papers) - Wingate, Ogée, Burlett, Bosc ►pdf
• Daily work with stable isotope spectroscopy instruments in Hesse forest - Plain, Parent, Longdoz, Marron, Epron ►pdf
• Experience with isotope-specific laser instrument - Brüggemann ►pdf
• Calibration for DXS: Measurements from Mauna Loa 2008 - Noone ►pdf
• Vertical profiles of water vapor isotopic composition from in-situ measurements - Noone, Risi, Bailey, Brown, Buenning, Nusbaumer, Sykes, Schneider, Vanderwende, Wong, Meillier, Wolf ►pdf

• Meeting Notes  ►pdf

 
MOTIVATION
We think it would be of importance to have our stable isotope community come up with solutions 
to better utilize the new spectroscopy technologies in continuous operation at field sites and 
prepare for future collaborative opportunities, e.g. within new observational networks.
 
GOAL
Discuss what works best and what did not work well, document these outcomes and report to 
the community.
 
MEETING SUMMARY
Introduction presentations, by the speakers listed below:
 
     1. Matthias J. Zeeman, Oregon State University, Corvallis (OR), USA.
     2. Rick Wehr, University of Arizona, Tucson (AZ), USA.
     3. Lisa Wingate, University of Cambridge, Cambridge, UK / University of Edinburgh, 
          Edinburgh, UK.
     4. Daniel Epron, University of Nancy / Université Henri Poincaré, Nancy, France.
     5. Nicolas Brueggemann, Forschungszentrum Jülich, Jülich, Germany.
     6. David Noone, University of Colorado, Boulder (CO), USA.
     7. Camille Risi, University of Colorado, Boulder (CO), USA.
 
The following topics were discussed:
 
At lab level
     ● Instrument characterization (lab, field) and calibration (field) are strongly application 
          dependent.
     ● Instrument characterization and calibration information should be added to papers (as 
          appendix)
     ● Instrument characterization
               ○ Instrument drift & precision (single gas, Allan variance statistics)
               ○ Response time & memory effects (step change, Allan variance statistics, (co)
                   spectra. turbulence measures) 
               ○ Cross sensitivity & interference (remove substance or correct, e.g. purging of the 
                   optical path, permeation drying of inlet gas)
              ○ Temperature sensitivity (analyze, stabilized ambient conditions, e.g. micro-dosing 
                  LN  for detectors, water cooling for lasers, air conditioning)
              ○ Effect of your sampling system (tube heating, below ambient pressure, effect of 
                  different tubing materials)
     ● Calibration
              ○ Check if the calibration response is linear.
              ○ Generally, a 2-3 points calibration based on individual isotopologues. Delta 
                  values derived from isotopologue mixing ratios only in a final step.  
              ○ Make sure that you bracket calibration well for the expected mixing and delta 
                  ratio range, as there are non-linear effects. Particularly important for labeling 
                  experiments.
              ○ Tie calibrations to mass spectrometer measurements.
     ● Keep spectra for long-term QC. Open questions: Data space considerations, info on how 
         to calibrate or use the spectra needs to be made available from manufacturers.
 
At community level
What could be helpful to share/compare/standardize within the community and how:
     ● Standardization and comparison of H2O isotope measurement setups: 
              ○ SMOW and Vostok standards do not cover the range found in the field; we need 
                  alternatives.
              ○ A performance test of currently used vaporizer systems and methods: through 
                  a ring exchange of liquid standards among labs, or the use of bottled Evian or 
                  Deep Blue as used at SIRFER (http://sirfer.utah.edu). 
     ● Standardization of CO2 isotope measurement setups
              ○ Tanks or flasks sources: IMECC, ICOS/NEON? 
              ○ Or produce your own flasks/tanks and sent it to mass spectrometer labs.
     ● Comparison of data processing: 
              ○ use of Golden files, similar to Ameriflux/CarboEuroflux, only for EC or just use 
                  existing CO2 golden files
     ● Reporting and communicating progress and issues:
              ○ Need for a new journal. For example, RCM is no longer accepting spectroscopy 
                  work (without IRMS). 
              ○ Exchange of information through BASIN (end of funding), NEON or SIBAE 
                  initiatives.
              ○ Peer-reviewed Wikis. For example, Prometheus (http://
                  prometheuswiki.publish.csiro.au); A CSIRO managed, peer-reviewed wiki 
                  for ‘Protocols in ecological & environmental plant physiology’
              ○ Manufacturer websites, e.g. Picarro forum.
          
Reporting of this meeting
     ● Online publication of the presentations and meeting notes.
              ○ BASIN: http://basin.yolasite.com/
              ○ SIBAE: http://www.sibae.ethz.ch/cost-sibae/
     ● Submit a meeting report to inform the broader community of our activities, e.g. to AGU’s EOS.
     ● An international, collaborative effort for “best practice” guidelines (or tech note 
         publication) is not considered at this time.
 
LIST OF ATTENDEES
 
The following (37) persons were present:
          

          Mark Blonquist                                                 David Nelson (Aerodyne)
          Dave Bowling                                                  David Noone
          Nicolas Brueggemann                                        Heath Powers
          Matthias Cuntz                                                 Thom Rahn
          Claudia Czimczik                                             Camille Risi
          Masako Dannoura                                              Adam Roddy
          Todd Dawson                                                   Scott Saleska
          Daniel Epron                                                    Greg Santoni
          Jim Ehleringer                                                 Ulli Seibt
          Iain Green (Picarro)                                          Rolf Siegwolf
          John Hunt                                                        Kevin Simonin
          Ali Ismail                                                         Kevin Tu
          Larry Jacobsen (Campbell Sci)                           Aaron Van Pelt (Picarro)
          Hans-Joerg Jost (Thermo-Fisher/ Novawave)      Bruce Vaughn
          Alexander Knohl                                               Eric Wapelhorst (Thermo-Fisher/ Novawave)
          Xuhui Lee                                                        Rick Wehr
          Hank Loescher                                                  Lisa Wingate
          Hongyan Luo                                                     Matthias Zeeman
          Dayle McDermitt (LI-COR)

ORGANIZERS
Matthias Zeeman (Oregon State University)
Alexander Knohl (ETH Zurich/U Goettingen)
Kevin Tu (UC Berkeley)
 
ACKNOWLEDGEMENT
This meeting was supported by BASIN. Many thanks to the speakers for presenting their work and making their presentations available.