GAW - Station Transfer Calibration LAB WCC - Empa

Field audit regional GAW station Jungfraujoch, Switzerland, January 1999 28 / 31
approx. concentration levels: 30 / 60 / 90 / 125 / 185 ppb
sequence of concentration: random
averaging interval per concentration: 5 minutes
number of runs: 3 before and 3 after audit
zero air supply: Pressurised air - zero air generator (CO catalyst,
Purafil, charcoal)
ozone generator: SRP's internal generator
data acquisition system: SRP's ADC and acquisition
ZERO AIR
GENERATOR
OZONE-
GENERATOR
Figure 16: Instruments set up SRP -TEI 49C-PS
SRP#15
2 cells (approx. 90 cm)
TEI 49C-PS
The stability of the transfer standard is thoroughly examined with respect to the uncertainties of the
different components (systematic error and precision). For the GAW transfer standard of the WCC-
O3 (TEI 49C-PS) the assessment criteria, taking into account the uncertainty of the SRP, are
defined to (1 ppb + 0.7%).
Figures 17 and 18 show the resulting linear regression and the corresponding 95% prediction
interval for the comparisons of TEI 49C-PS vs. SRP#15. Clearly, the linear regression and the
prediction interval remain within the recommended tolerance.
WMO Global Atmosphere Watch World Calibration Centre for Surface Ozone and Carbon Monoxide