Demonstration of an off-axis parabolic receiver for near-range retrieval of lidar ozone profiles
Abstract. During the 2017 Ozone Water Land Environmental Transition Study (OWLETS), the
Langley mobile ozone lidar system utilized a new small diameter receiver to
improve the retrieval of near-surface signals from 0.1 to 1 km in altitude.
This new receiver utilizes a single 90  ∘ fiber-coupled, off-axis
parabolic mirror resulting in a compact form that is easy to align. The
single reflective surface offers the opportunity to easily expand its use to
multiple wavelengths for additional measurement channels such as visible
wavelength aerosol measurements. Detailed results compare the performance of
the receiver to both ozonesonde and in situ measurements from a UAV platform,
validating the performance of the near-surface ozone retrievals. Absolute
 O3 differences averaged 7 % between lidar and ozonesonde data
from 0.1 to 1.0 km and yielded a 2.3 % high bias in the lidar data, well
within the uncertainty of the sonde measurements. Conversely, lidar
 O3 measurements from 0.1 to 0.2 km averaged 10.5 % lower than
coincident UAV O3 . A more detailed study under more stable
atmospheric conditions would be necessary to resolve the residual instrument
differences reported in this work. Nevertheless, this unique added capability
is a significant improvement allowing for near-surface observation of ozone.