WMO/IAEA Round Robin experimental details and recommended guidelines.

Important! - PROCEDURAL MODIFICATIONS

The Round Robin experimental setup has been modified in an effort to complete the experiment in one year. The following list summarizes key changes.

  • Participation in the Round Robin requires your agreement to 1) enter all required information on this web site in a timely manner and 2) forward the WMO cylinders on to the next scheduled participant at the end of your allotted time even if all measurements have not been completed.

  • All participants must use wmorr@noaa.gov for all WMO/IAEA Round Robin correspondence to the NOAA coordinating team.

  • The experiment will include 5 circuits of 2 cylinders each. As in previous Round Robin experiments, air in each cylinder will be near ambient range of CO2, CH4, CO, H2, N2O, SF6, O2/N2, and δ13C and δ18O of CO2.

  • Participants will no longer report results directly to the WMO Round Robin referee.

  • Participants will manage their account information and report results and cylinder arrival and shipping information using secure online web forms. Access requires a username and password.

  • Participants are required to update their account information using the online Account Information form as soon as possible after receiving their username and password.

  • Participants will be notified one week prior to when cylinders are scheduled to arrive at their location. This is to help participants prepare for their arrival and ensure timely measurement of the 2 cylinders.

  • Participants will be notified as they approach the end of their allotted measurement time.

  • Participants are required to document the arrival of the WMO cylinders at their location using the online Cylinder Receiving form. Timely entry of this information is critical as it will ensure that you receive your full allotment of measurement time.

  • Participants are required to document their shipping of the WMO cylinders using the online Cylinder Shipping form. Timely entry of this information is critical as it ensures that the next participant has adequate time to prepare for the arrival and measurement of the WMO cylinders.

  • Participants are required to report their results directly to this web site using the online results form as soon as possible after completing their measurements.

  • Participants will report one and only one measurement value and uncertainty for each WMO Round Robin cylinder measured. The reported uncertainty will be based on measurement reproducibility.

PARTICIPATION

The NOAA team will e-mail the WMO/IAEA GGMT (Meeting on Carbon Dioxide, Other Greenhouse Gases, and Related Measurement Techniques) mailing list of the upcoming Round Robin experiment. You are encouraged to participate if you are making ongoing, high-precision atmospheric measurements of CO2 and maintain a laboratory CO2 scale. If you would like to participate, please reply before the deadline to ensure your request will be given full consideration.

If you reply "yes", you will then be sent instructions on how to access your WMO Round Robin account. Please log in to your account and complete the Account Information form as soon as possible. If you already have an account, you will be asked to verify your information and update content as required.

Important! Please be sure to provide all of the requested information. Incomplete information will delay our ability to process your request. Once we compile all requests, we will notify you regarding your participation status. Further information is available below (see Reporting: Account Information).

EXPERIMENTAL SETUP

There will be 5 circuits with two cylinders assigned to each circuit. You will be informed before receiving the WMO cylinders. Please give high priority to the measurement of the WMO cylinders to ensure the experiment is not delayed. You must complete measurements within your allotted time.

Your allotted time will be

  • two (2) weeks if measuring CO2 only or CO2 and one additional trace gas species
  • three (3) weeks if measuring 3 trace gas species
  • four (4) weeks if measuring more than 3 species and/or the stable isotopes of CO2

At the end of your allotted time, cylinders must to be forwarded, finished or not, to the next scheduled participant. Please note: In the event a participant is unable to complete measurements of the 2 cylinders in the allotted time, they will be required to ship the set on to the next participant without completion. We must adhere to this strategy to ensure that all participants receive their full allotted measurement time. Participants who are unable to complete their measurements may request (at their own expense) to have the cylinders returned to their facility after the Round Robin experiment is completed. Values reported or updated after the closure date are logged but will not be included in the experiment results.

With the exception of using the provided regulators, please treat the measurement of WMO cylinders in the same manner as standards in your program. The WMO cylinders are to be measured at your primary measurement facility only. Do not circulate the WMO cylinders within your network.

RECOMMENDATIONS FOR HANDLING REGULATORS

There is a dedicated regulator for each WMO cylinder. These are to be installed, leak checked, flushed and conditioned before measurement. For measurement integrity, keep the regulator attached until all species are measured.

Regulator Installation
Install the regulator to the cylinder using reasonable torque to achieve a seal. Install an unattached quick connector fitting to the outlet (to make the port connector open). With the regulator delivery pressure knob fully off (counter clock wise) and the regulator delivery valve closed, momentarily open and close the cylinder valve. If the CGA connection audible leaks, remove, INSPECT BOTH PARTS FOR DEBRIS, clean with something lint free, and reattach. Repeat. With no audible leaking and cylinder valve closed, open delivery valve and increase pressure delivery to bleed off all pressure.

Leak Check
Open and close the tank valve, set the delivery pressure to 20 psi. Close the regulator delivery valve. Use Snoop or equivalent leak checking liquid on the CGA connection to assure no minor leaks exist. If they do, add some torque to the CGA nut until sealed. Once a seal is made, flush.

  1. Open the delivery valve and let all pressure bleed off to zero.
  2. Close delivery valve and open then close the cylinder valve so all sections pressurize.
  3. Open the delivery valve and let all pressure bleed off to zero.
Repeat steps 2 and 3 four times. Remove the quick connector that allowed the air to bleed out.

Open and then close the tank valve and let sit fully pressurized for at least 24 hours. If no great pressure change is evident, the cylinder is ready to measure. If more than a few 100 psi are lost, there may be a small leak somewhere else which needs investigation.

Pre-measurement Flush
Before measurement, attach to manifold, open and close the tank valve, allow the regulator to bleed out to zero pressure, through your delivery system, then with your flow to the measurement system off, open tank valve and proceed with your measurement protocol.

For further detailed procedures, please visit www.esrl.noaa.gov/gmd/ccl/reg.guide.html.

REPORTING

Account Information
Participants are required to provide and update their account information using the on-line Account Information form. This information is required before the Round Robin schedule can be set.

The account information form includes the following fields. All fields are required unless otherwise noted.

  • Primary Contact: Name of primary contact. If you would like to change the Primary Contact, please contact the NOAA Team.
  • Primary Email: E-mail address of primary contact.
  • Secondary Email Contacts: Please provide at least one additional e-mail contact in the event the primary contact is unavailable. Provide addresses for yourself and others (separated by comma) (ex) email2,email3,email4, ...
  • Intended Measurements: Identify all parameters you intend to measure in the WMO cylinders.
  • Blackout Periods [optional]: Specify time periods in which you are unable to receive and measure the WMO cylinders.
  • Telephone: Please include country access code.
  • Fax [optional]: Please include country access code.
  • Shipping Address: Please include Receiving contact, Telephone number of receiving contact, and Customs Broker.
  • Shipping Instructions [options]: Any additional information useful to ensure proper shipping.
  • Additional Notes [optional]

Cylinder Arrival
Participants are required to use the on-line Cylinder Arrival form to report the date on which the WMO cylinders arrive at their laboratory. Timely entry of this information is critical as it will ensure that you receive your full allotment of measurement time.

The cylinder arrival form includes the following fields. All fields are required unless otherwise noted.

  • Arrival Date: Date on which the WMO cylinders arrive at your facility.

Cylinder Shipping
Participants are required to use the on-line Cylinder Shipping form to report when they have shipped the WMO cylinders on to the next laboratory. Timely entry of this information is critical to ensure that the next participant has adequate time to prepare for the arrival and measurement of the WMO cylinders.

The cylinder shipping form includes the following fields. All fields are required unless otherwise noted.

  • Cylinder Pressure (psig) prior to any measurements in your lab.
  • Shipping Date: Date on which the WMO cylinders are shipped from your facility to the next WMO participant.
  • Notes [optional]

Measurement Results
Participants will report their results using the on-line Measurement Report form. Please DO NOT send results to the WMO Round Robin referee. Results will include a single measurement value and estimated uncertainty for each WMO cylinder and trace gas or isotope measured. You may update your results as many times as necessary. Only the most recent entry will be used to compile comparison results once the experiment is completed. Results submitted after the experiment closure date will not be considered in the summary of comparison results.

The measurement report form includes the following fields. All fields are required unless otherwise noted.

  • Measurement Date (yyyy-mm-dd): Date on which the measurement is completed.
  • Measurement Value
  • Measurement Uncertainty: The estimated uncertainty should be based on measurement reproducibility. Do not include uncertainties associated with your primary standards.
  • Number of Measurements [optional]: The number of individual measurements contributing to the reported value.
  • Uncertainty Comment [optional]: Additional description of how uncertainty is estimated.
  • Calibration Scale: Select the appropriate scale from the pulldown menu. If the scale is not included in the pulldown list, please contact the NOAA Team.
  • Detection Method: Select the appropriate detection method from the pulldown menu. If the detection method is not included in the pulldown list, please contact the NOAA Team.
  • Instrument ID [optional]: Model or serial number of detection instrument.
  • Notes [optional]: Additional information deemed useful to other participants or referee.
  • References [optional]: Published work relevant to the WMO/IAEA Round Robin experiment and results.