Errors of pure rotational Raman lidar absolute calibration due to collisional line broadening
V.V. Gerasimov
V.E. Zuev Institute of Atmospheric Optics of Siberian Branch of the Russian Academy of Science, Tomsk, Russia
Keywords: Raman scattering, lidar, spectral line broadening, lidar calibration, tropospheric temperature
Abstract
The effect of collisional line broadening on the accuracy of tropospheric (0-11 km) temperature measurements with pure rotational Raman (PPR) lidars at their absolute calibration by spectroscopic parameters was estimated via numerical simulation. The simulation was performed for five sets of spectral filters (SF) with different passbands in a lidar spectral selection unit and an outgoing laser signal wavelength of 355 nm. It is shown that the unavoidable absolute calibration error can reach values from 0.14 to 0.44 K (depending on the SF set) when ignoring the N2 and O2 PRR line broadening. The line broadening can be neglected if only one PRR line is extracted in each of the two lidar channels (for example, using a Fabry-Perot interferometer).
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