Accurate lidar temperatures with narrowband filters

At daytime, metal resonance lidars need narrowband spectral filtering in the receiver to measure Doppler temperatures in the mesopause region. For our K lidar equipped with a Faraday anomalous dispersion optical filter we demonstrate that the derived resonance temperatures can be shifted by 10 K because of the wavelength dependence of the filter transmission for the Rayleigh scattered light when this filter transmission is used for normalization. We show that, if all filter effects are considered correctly, temperature measurements at daytime can be as accurate as at nighttime without such filters.