Uncertainty of ozone measurements with the primary standard reference photometer (SRP45)

Abstract

A comparison of the ozone primary reference standard photometer serial number 45 (SRP45) against the National Institute of Standards and Technology (NIST) instruments, serial number 0 (SRP0) and 2 (SRP2), has been performed in order to establish the traceability and comparability of ozone measurements made by the Chilean atmospheric science community. A complete uncertainty budget was developed for SRP45, using a GUM approach. The results of the comparisons allow us to conclude that SRP45, SRP0 and SRP2 are comparable according to internationals criteria over an ozone mole fraction range of 0 nmol mol−1 to at least 500 nmol mol−1. The official result for the validation of SRP45 is xSRP45 ozone = [0.013 + 0.99806xSRP2 ozone] nmol mol−1 with an expanded uncertainty of 2 ×

(0.27)2 + (1.18 × 10−2 × xozone)2 from 0 to 500 nmol mol−1.