Japan Meteorological Agency (JMA)
Summary of CO2 Calibration and Standard Scales at Different Laboratories

The NOAA Climate Monitoring and Diagnostics Laboratory (CMDL) in Boulder, Colorado, USA has been designated by WMO as the Central CO2 Calibration Laboratory responsible for maintaining the GAW Reference Standard for CO2. In its role as the World Calibration Centre (WCC) for CO2, CMDL maintains a high-precision manometric system for absolute calibration of CO2 reference gases to prepare and/or calibrate the CO2 standards gases used for GAW measurements worldwide [Zhao et al., 1997]. It is recommended that the standards of GAW measurement laboratories be calibrated on a regular basis (such as every two years) at the CCL. In 1995, CMDL took over the role of CCL from the Scripps Institution of Oceanography (SIO) in San Diego, California, USA.
Under the WMO calibration system, several calibration scales exist for CO2 data, e.g. X74, X85, X87, X93 and the WMO Mole Fraction Scale. The WMO Xyy Scales were traceable to the primary standards of the former CCL at SIO, while the WMO Mole Fraction Scale was traceable to those at CMDL. CMDL showed no significant offset between the WMO Mole Fraction Scale and the Xyy Scales through repeated intercalibration with the primary standards of SIO [GLOBALVIEW-CO2, 2001].
To assess differences in standard scales among CO2 measuring laboratories, CMDL organizes intercomparison or round-robin experiments endorsed by WMO every few years. Many laboratories participated in the experiments organized in 1991-1992, 1995-1997 and 1999-2000. In addition, many laboratories compare their standards bilaterally or multilaterally among themselves.
The table below lists laboratories contributing CO2 measurement data to WDCGG or other laboratories involved in CO2 measurement with standard scales of reported data and participation history in WMO intercomparison experiments.

Table: Status of CO2 Calibration Scales and Intercomparison as of June 2002
(WDCGG Site Index)
Reported Standard ScaleMost Recent CalibrationWMO Round Robin
CSIROCGR540S0, CSIRO Flask Network**WMO2001-11 at CMDL91/92, 95/97, 99/00
NIWABAR541S0 SIO 19951995-11 at SIO91/92, 95/97, 99/00
CAMSWLG236N0X931994-01 at SIO95/97, 99/00
JMANMN224N0, RYO239N0, YON224N0, ALG99990, EOM99990, RYF99990WMO1999-03 at CMDL91/92, 95/97, 99/00
MRITKB236N0, INS9999A, HKH99990, KIY99990, NTU99990, RFM99990, WLT99990MRI 1997 91/92, 95/97, 99/00
NIESCOI243N0, HAT224N0NIES 95 95/97, 99/00
TohokuSYO769S0Tohoku 91/92, 95/97, 99/00
ShizuokaHMM234N0 Nippon Sanso  
SaitamaDDR236N0, URW235N0WMOJMA 
CMDLBRW471N0, MLO519N0, SPO789S0, SMO514S0, CMDL flask network*WMO2001-01 at CMDL91/92, 95/97, 99/00
NIST NIST 91/92, 95/97, 99/00
SIO SIO 91/92, 95/97, 99/00
MSCALT482N0, CSJ451N0, SBL443N0SIO 19912000-03 at CMDL91/92, 95/97, 99/00
MGOBER255N0, KOT276N0, KYZ240N0, STC652N0, TER669N0X971991 at SIO 
INMIZA128N0X87, X931997-01 at CMDL91/92, 95/97, 99/00
LSCEAMS137S0, MCH653N0X931998-08 at CMDL91/92, 95/97, 99/00
IMSCMN644N0X931998-10 at CMDL91/92, 95/97
ENEALMP635N0X932000-08 at CMDL91/92, 95/97, 99/00
CESIPLR645N00X851997-07 at CMDL99/00
UBABRT648N0, DEU649N0, NGL653N0, SSL647N0, LGB652N0, WST654N0, ZGT654N0, ZGP647N0WMO1998-10 at CMDL91/92, 95/97, 99/00
Heidelberg WMO1998-10 at CMDL95/97, 99/00
IFUWNK647N0, ZSP647N00SIO 1974 99/00
MISU/NILUZEP678N0X931996-07 at CMDL95/97, 99/00
HMSKPS646N0WMO 19852000-03 at CMDL91/92, 95/97, 99/00
NIMHFDT645N20 SIAD SpA, Italy 
SAWSCPO134S0WMO1997-06 at CMDL99/00
* CMDL flask network: ALT482N10, AMS137S10, ASC107S10, ASK123N10, BAL655N10, BRW471N10, SGI354S10, BSC644N10, NMB123S10, CGO540S10, KUM519N10, CHR501N10, CBA455N10, CRZ146S10, GOZ636N10, EIC329S10, ITN435N10, GMI513N10, HBA775S10, HUN646N10, ICE663N10, KEY425N10, MHD653N10, SEY104S10, MLO519N10, MBC476N10, WLG236N10, NWR440N10, ZEP678N10, STC654N10, STM666N10, POC9XXX10, PSA764S10, LEF445N10, RPB413N10, MID528N10, WIS631N10, SHM452N10, SCS9XXX10, SPO789S10, BMW432N10, AVI417N10, BME432N10, SYO769S10, TAP236N10, AZR638N10, TDF354S10, SMO514S10, UUM244N10, UTA439N10
** CSIRO flask network: AIA999930, ALT482N30, CFA519S30, CGR540S30, EPC449N30, MQA554S30, MLO519N30, MAA767N30, SIS660N30, SPO789S30
Aichi:Aichi Prefecture, Japan
CAMS: Chinese Academy of Meteorological Sciences, China Meteorological Administration
CESI:Italian Electrical Experimental Center
CNR:Istituto di Fisica dell'Atmosfera, Consiglio Nazionale delle Ricerche, Italy
CMDL:Climate Monitoring and Diagnostics Laboratory, NOAA, USA
CSIRO: Commonwealth Scientific and Industrial Research Organisation, Australia
ENEA: Italian National Agency for New Technology, Energy and the Environment
HMS: Hungarian Meteorological Service
IFU:Fraunhofer-Institut fur Atmospharische Umweltforschung, Germany
IGP:Instituto Geofisico del Peru
INM:Instituto Nacional de Meteorologia, Spain
IMS: Centro Aeronautico di Montagna, Italian Air Force Meteorological Service
JMA: Atmospheric Environment Division, Japan Meteorological Agency
KSNU:Kyrgyz State National University
LSCE:Laboratoire des Sciences du Climat et de l'Environnement, CEA-CNRS, France
METRI:Meteorological Research Institute, Korea Meteorological Administration
MGO:Main Geophysical Observatory, Russian Federation
MISU:Department of Meteorology, Stockholm University, Sweden
MRI: Meteorological Research Institute, Japan Meteorological Agency
MSC:Meteorological Service of Canada
NIES: National Institute for Environmental Studies, Japan
NILU:Norwegian Institute for Air Research
NIMH:Institutul National de Meteorologie, Hidrologie si Gospodarirea Apelor, Romania
NIST:National Institute of Standards and Technology, USA
NIWA: National Institute of Water and Atmospheric Research, New Zealand
RIVM:National Institute for Health and Environment, Netherlands
Saitama:Saitama Prefecture, Japan
SAWS:South African Weather Service
Shizuoka:Shizuoka University, Japan
SIO:Scripps Institution of Oceanography, USA
SNU: Seoul National University, Republic of Korea
Tohoku: Tohoku University, Japan
UBA: Umweltbundesamt, Germany
UHEI-IUP: Institut fur Umweltphysik, Universitat Heidelberg, Germany
ZAMG:Central Institute of Meteorology and Geodynamics, Austria

Zhao, C.L., P. P Tans, and K. W. Thoning, A high precision manometric system for absolute calibrations of CO2 in dry air, J. Geophys. Res., 102, 5885-5894, 1997.
GLOBALVIEW-CO2: Cooperative Atmospheric Data Integration Project - Carbon Dioxide. CD-ROM, NOAA CMDL, Boulder, Colorado [Also available on Internet via anonymous FTP to ftp.cmdl.noaa.gov, Path: ccg/co2/GLOBALVIEW], 2001.

Last Updated: 2008.04.07