title: Development of a Northern Continental Air Standard Reference Material.
abstract: The National Institute of Standards and Technology (NIST) recently began to develop standard mixtures of greenhouse gases as part of a broad program mandated by the 2009 United States Congress to support research in climate change. To this end, NIST developed suites of gravimetrically assigned primary standard mixtures (PSMs) comprising carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O) in a dry-natural air balance at ambient mole fraction levels. In parallel, the National Oceanic and Atmospheric Administration (NOAA) in Boulder, Colorado, charged 30 aluminum gas cylinders with northern hemisphere air at Niwot Ridge, Colorado. These mixtures, which constitute NIST Standard Reference Material (SRM) 1720 Northern Continental Air, were certified by NIST for ambient mole fractions of CO2, CH4, and N2O relative to NIST PSMs. NOAA-assigned values are also provided as information in support of the World Meteorological Organization (WMO) Global Atmosphere Watch (GAW) Program for CO2, CH4, and N2O, since NOAA serves as the WMO Central Calibration Laboratory (CCL) for CO2, CH4, and N2O. Relative expanded uncertainties at the 95% confidence interval are <±0.06% of the certified values for CO2 and N2O and <0.2% for CH4, which represents the smallest relative uncertainties specified to date for a gaseous SRM produced by NIST. Agreement between the NOAA (WMO/GAW) and NIST values based on their respective calibration standards suites is within 0.05%, 0.13%, and 0.06% for CO2, CH4, and N2O, respectively. This collaborative development effort also represents the first of its kind for a gaseous SRM developed by NIST.
authors.affiliation: Gas Sensing Metrology Group Chemical Sciences Division Materials Measurement Laboratory, National Institute of Standards and Technology , 100 Bureau Drive, Gaithersburg, Maryland 20899-8393, United States.
authors.forename: George C
authors.initials: GC
authors.lastname: Rhoderick
authors.affiliation: Global Monitoring Division Earth System Research Laboratory, National Oceanic and Atmospheric Administration (NOAA) , 325 Broadway, Boulder, Colorado 80305, United States.
authors.forename: Duane R
authors.initials: DR
authors.lastname: Kitzis
authors.affiliation: Gas Sensing Metrology Group Chemical Sciences Division Materials Measurement Laboratory, National Institute of Standards and Technology , 100 Bureau Drive, Gaithersburg, Maryland 20899-8393, United States.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Kelley
authors.affiliation: Gas Sensing Metrology Group Chemical Sciences Division Materials Measurement Laboratory, National Institute of Standards and Technology , 100 Bureau Drive, Gaithersburg, Maryland 20899-8393, United States.
authors.forename: Walter R
authors.initials: WR
authors.lastname: Miller
authors.affiliation: Global Monitoring Division Earth System Research Laboratory, National Oceanic and Atmospheric Administration (NOAA) , 325 Broadway, Boulder, Colorado 80305, United States.
authors.forename: Bradley D
authors.initials: BD
authors.lastname: Hall
authors.affiliation: Global Monitoring Division Earth System Research Laboratory, National Oceanic and Atmospheric Administration (NOAA) , 325 Broadway, Boulder, Colorado 80305, United States.
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Dlugokencky
authors.affiliation: Global Monitoring Division Earth System Research Laboratory, National Oceanic and Atmospheric Administration (NOAA) , 325 Broadway, Boulder, Colorado 80305, United States.
authors.forename: Pieter P
authors.initials: PP
authors.lastname: Tans
authors.affiliation: Statistical Engineering Division National Institute of Standards and Technology 100 Bureau Drive Gaithersburg, Maryland 20899-8980 United States.
authors.forename: Antonio
authors.initials: A
authors.lastname: Possolo
authors.affiliation: Gas Sensing Metrology Group Chemical Sciences Division Materials Measurement Laboratory, National Institute of Standards and Technology , 100 Bureau Drive, Gaithersburg, Maryland 20899-8393, United States.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Carney