Table 6.

Summary of the average uncertainty estimates for the LJO analyzer during 2015. Each component of the total measurement uncertainty is listed, where ${\overline{U}}_{\text{air}}$ is the total mean annual uncertainty in the air measurements collected during 2015 and calculated as described by Eqs. (5)–(7), ${\overline{U}}_{\text{excess}}$ is the average annual uncertainty in the enhancement, U_h2o is the uncertainty due to the treatment of water vapor, ${\overline{U}}_{\text{TGT}}$ is the mean uncertainty derived from the target tank measurements, ${\overline{U}}_{\text{p}}$ is the mean analyzer precision, ${\overline{U}}_{\text{b}}$ is the mean calibration baseline uncertainty, and ${\overline{U}}_{\text{extrap}}$ is the extrapolation uncertainty, or the uncertainty due to the single-point calibration strategy, which was estimated using a mean ε for nine analyzers (see text and Supplement).

Uncertainty estimates	CO2 (ppm)	CH4(ppb)
Uh2o	0.0233	0.221
Uscale	0.03	0.31
${\overline{U}}_{\text{TGT}}$	0.0166	0.2126
${\overline{U}}_{\text{p}}$	0.0242	0.2205
${\overline{U}}_{\text{b}}$	0.0028	0.0444
${\overline{U}}_{\text{extrap}}$	0.0477	0.4618
${\overline{U}}_{\text{air}}$	0.0699	0.7224
${\overline{U}}_{\text{excess}}$	1.36	11.89