@misc{10481/62730,
year = {2020},
month = {5},
url = {http://hdl.handle.net/10481/62730},
abstract = {Doppler lidars provide two measured parameters, radial velocity and signal-to-noise ratio, from which
winds and turbulent properties are routinely derived. Attenuated backscatter, which gives quantitative information on
aerosols, clouds, and precipitation in the atmosphere, can
be used in conjunction with the winds and turbulent properties to create a sophisticated classification of the state
of the atmospheric boundary layer. Calculating attenuated
backscatter from the signal-to-noise ratio requires accurate
knowledge of the telescope focus function, which is usually unavailable. Inaccurate assumptions of the telescope focus function can significantly deform attenuated backscatter
profiles, even if the instrument is focused at infinity. Here,
we present a methodology for deriving the telescope focus
function using a co-located ceilometer for pulsed heterodyne
Doppler lidars. The method was tested with Halo Photonics
StreamLine and StreamLine XR Doppler lidars but should
also be applicable to other pulsed heterodyne Doppler lidar
systems. The method derives two parameters of the telescope
focus function, the effective beam diameter and the effective focal length of the telescope. Additionally, the method
provides uncertainty estimates for the retrieved attenuated
backscatter profile arising from uncertainties in deriving the
telescope function, together with standard measurement uncertainties from the signal-to-noise ratio. The method is best
suited for locations where the absolute difference in aerosol
extinction at the ceilometer and Doppler lidar wavelengths is
small.},
organization = {This research has been supported by the U.S.
Department of Energy’s Atmospheric System Research (ASR),
an Office of Science, Office of Biological and Environmental
Research (BER) programme (grant no. DE-SC0017338).},
publisher = {European Geosciences Union},
title = {Methodology for deriving the telescope focus function and its uncertainty for a heterodyne pulsed Doppler lidar},
doi = {10.5194/amt-13-2849-2020},
author = {Pentikäinen, Pyry and Ortiz-Amezcua, Pablo},
}