NCAR NOxyO3 Instrument

PI:  Andrew J. Weinheimer  (wein@ucar.edu)

Affiliation:  National Center for Atmospheric Research

Measurements:  NO, NO2, NOy, O3

Scientific Objectives:
These measurements will address several scientific questions and are most directly relevant to objective [D], with the O3 and NOx measurements crucial to assessing the oxidizing capacity of the Arctic boundary layer, through impacts on the local HOx and NO3 chemistries, as well as on the PAN/acetaldehyde chemistry, which can have long-range effects.  The measurements of O3 and NOy are useful for air mass characterization (polluted, ODE, etc.), and will reflect source regions as well as boundary layer stability (objective [F]).  Additionally, measurements of NOx will reflect the impact of emissions from the snowpack (objective [B]).

Measurement Technique:

We will deploy at the Barrow ground site a 4-channel chemiluminescence instrument for the measurement of NO, NO2, NOy, and O3.  NO is measured via its chemiluminescent reaction with reagent O3 that is added to the sample flow.  NO2 is measured after photolytic conversion to NO.  NOy (total reactive nitrogen) is measured after catalytic conversion to NO in the presence of CO.  O3 is measured via the same chemiluminescent reaction with the addition of pure NO to the sample flow.  Photon counting is used for all four channels, with NOy and O3 being measured at ~1-s, and NO and NO2 at ~ 3-s, subject to the constraints imposed by the inlet (TBD?).