Isotope analysis of atmospheric trace gases

Isotope analysis of multiple atmospheric trace gases in atmospheric air samples and reference standards from the GGGRN and related programs. Aliquots are to be taken from a) pairs of 2.2 liter sample flasks in the global network, b) samples within Programmable Flask Packages (PFPs), and c) reference standard cylinders. Precision requirements are those deemed necessary for scientifically meaningful detection of expected gradients within the atmosphere and are detailed below. Processing and measurement requirements: Stable isotopes of Carbon Dioxide (CO2): Provide quantitative isotopic measurement from whole-air atmospheric samples for carbon dioxide including d 13C and d 18O. Results to be reported in per mil () relative to and on scales established by international (IAEA) primary reference materials. The reproducibility of the measurements should be - 0.02 - and - 0.05 - for carbon and oxygen respectively. Measurements will be done on 500 cc of air or less. The long term measurement performance must be demonstrated based on past performance in measuring repeat measurements from control cylinders. Radiocarbon (14C) of Carbon Dioxide (CO2): Provide i) quantitative, cryogenic extraction and purification of CO2 from whole-air atmospheric samples, ii) graphitization, and iii) AMS 14C measurement with iv) combined, long-term (multi-year) external measurement repeatability of 2 - or better (1-sigma on D 14C scale). The long-term measurement performance must be demonstrated based on past performance in measuring repeat extraction aliquots of whole air from control cylinders. Radiocarbon (14C) of Methane (CH4): Provide i) purification of CH4 from whole-air atmospheric samples and quantitative conversion to CO2 for , ii) graphitization, and iii) AMS 14C measurements with iv) external measurement precision of ? 4 - as determined from pair differences or repeat measurement control materials. Stable isotopes of Methane (CH4): Provide quantitative isotopic measurement from whole-air atmospheric samples for methane including d 13C and d D. Results to be reported in per mil () relative to and on scales established by international (IAEA) primary reference materials. The reproducibility of the measurements should be - 0.08 - and - 2 - for carbon and hydrogen respectively. Measurements will be done on total of 200cc of air or less for both isotopes. The long term measurement performance must be demonstrated based on past performance in measuring repeat measurements from control cylinders. Sample turn-around time: Provide in-lab sample container turnaround time of 50 calendar days or less for individual air samples, in the potential case of each sample having the full suite of analysis tasks a., b., c., and d. performed and completed (as outlined above). It is anticipated that longer delays might be occasionally necessary as instrument downtime dictates, recognizing that these are difficult and not routine measurements. Measurement capacity: Stable isotopes of Carbon Dioxide (CO2): Provide analysis of up to 20,000 samples per year.. Radiocarbon (14C) of Carbon Dioxide (CO2): Provide for extraction of up to 5,000 authentic samples per year and measurement of 1,000 to 3,000 authentic samples per year.. Radiocarbon (14C ) of Methane (CH4): Provide analysis of up to 400 samples per year.. Stable Isotopes of Methane (CH4): Provide analysis of up to 10,000 samples per year. Data management and traceability: The laboratory (or laboratories) will be expected to have traceability to international reference materials that place sample data on established measurement scales. Data should be available that will allow all samples to be post processed at any time to account for subsequent adjustments to reference scales. The laboratory (or laboratories) will be expected to provide processed initial results and subsequent QC revisions using NOAA IT approved remote access methodologies and CCGG group provided data processing routines to merge datasets into the primary data base repository. The lab(s) must be able to adjust the format and contents of result data files to meet changing requirements of the ingest systems as needed. The laboratory (or laboratories) will be expected to participate in inter-comparison exercises with other labs around the world. This will document the ability of NOAA produced data to be used in conjunction with other data sets without significant scale offsets or measurement artifacts. Coordination will be made with the NOAA GGGRN to make data freely available for this effort.