Intercomparison of lidar, aircraft, and surface ozone measurements in the San Joaquin Valley during the California Baseline Ozone Transport Study (CABOTS)
Abstract. The California Baseline Ozone Transport Study (CABOTS) was
conducted in the late spring and summer of 2016 to investigate the influence
of long-range transport and stratospheric intrusions on surface ozone
( O3 ) concentrations in California with emphasis on the San Joaquin
Valley (SJV), one of two extreme ozone non-attainment areas in the US.
One of the major objectives of CABOTS was to characterize the vertical
distribution of O3 and aerosols above the SJV to aid in the
identification of elevated transport layers and assess their surface
impacts. To this end, the NOAA Earth System Research Laboratory (ESRL)
deployed the Tunable Optical Profiler for Aerosol and oZone (TOPAZ) mobile
lidar to the Visalia Municipal Airport (36.315 ∘  N,
119.392 ∘  E) in the central SJV between 27 May and 7 August 2016.
Here we compare the TOPAZ ozone retrievals with co-located in situ surface
measurements and nearby regulatory monitors and also with airborne in situ measurements
from the University of California at Davis–Scientific Aviation (SciAv)
Mooney and NASA Alpha Jet Atmospheric eXperiment (AJAX) research aircraft.
Our analysis shows that the lidar and aircraft measurements agree, on
average to within 5 ppbv, the sum of their stated uncertainties of 3 and 2 ppbv, respectively.