Peroxy radicals measured during Mauna Loa Observatory Photochemistry Experiment 2: The data and first analysis

Abstract

Peroxy radicals were measured using chemical amplification during the four intensive measurement periods of the Mauna Loa Observatory Photochemistry Experiment (MLOPEX 2) campaign from September 1991 to August 1992. One‐minute average radical concentrations were obtained with overall uncertainties of 8 to 16 parts per trillion by volume (pptv), depending on the variability of ambient ozone. Thirty‐minute averaged concentrations have uncertainties of ±30%. The peroxy radicals exhibited diurnal behavior expected of an atmospheric species with photochemical origins and correlated with a simple expression that describes radical formation and loss. The application of a steady state analysis to the radical levels suggested that for some conditions, loss processes other than gas phase chemistry may be required to explain the observed concentrations.