GAW calibration centres are either global (WCCs) or regional (RCCs) in responsibility.  The centres are operated by institutions participating in the GAW Programme. The main tasks of the calibration centers are to link observations to World Reference Standards and to ensure network comparability/compatibility through intercomparison campaigns and regular audits.

Terms of Reference for World and/or Regional Calibration Centres (WCCs, RCCs)

•  Assist Members operating GAW stations to link their observations to the GAW primary standard.
•   Develop quality control procedures following the recommendations by the SAGs, support the QA of specific measurements and ensure the traceability of these measurements to the corresponding primary standard.
•   Maintain laboratory and transfer standards that are traceable to the primary standard.
•   Perform regular calibrations and performance audits at GAW sites using transfer standards in co-operation with the established RCCs.
•   Provide, in co-operation with the QA/SACs, training and long-term technical help for stations.

All WCCs and RCCs can be found under "Central Facilities"