Probing the analytical cancellation factor relation using Na lidar and
nightglow data from the Andes Lidar Observatory
Abstract
The cancellation factor (CF) is a model for the ratio between gravity
wave perturbations in the airglow intensity to those in the ambient
temperature and is necessary to estimate the momentum and energy flux
and flux divergence of gravity waves in the airglow emissions. This
study tests the CF model using T/W Na Lidar data and zenith nightglow
observations of the OH and O(1S) emissions. The dataset analyzed was
obtained during the campaigns carried out in 2015, 2016, and 2017 at the
Andes Lidar Observatory (ALO) in Chile. We have used an empirical method
to fit the analytical function that describes the CF for vertically
propagating waves and compared the quantities through the ratio of
airglow wave amplitude registered as a dominant event in the images to
the wave amplitude in the lidar temperature. We show that the analytical
relationship underestimates the observational results. We obtained good
agreement with respect to the theoretical value for the O(1S) emission
line. In contrast, the observational CF ratio deviates by a factor of
~2 from the analytical value for the OH emission.