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Rayleigh and sodium lidar system incorporating time-division and wavelength-division multiplexing

Abstract:

In this study, we report a Rayleigh and sodium lidar system, which was recently upgraded at the University of Science and Technology of China (USTC) in Hefei, China (31.5 °N, 117 °E). The lidar system features high temporal and vertical resolutions, a high signal-to-noise ratio (SNR) and mobility. Using the time-division and wavelength-division multiplexing methods, only one piece of photomultiplier tube is used in the optical receiver, which makes the system compact and robust. Wideband filtering and narrowband filtering are both used in the lidar system to obtain high SNR data under city lights. The lidar system was established on 24 September 2016 and has run stably for 2 years. Meteor trail events that lasted for only a few seconds were extracted from the high resolution, high SNR observational data. The sodium observational data in 2017 were fitted annually and semiannually, and the results were similar to those obtained in previous studies. The monthly average atmospheric temperature showed semiannual variations. Stratospheric aerosols were observed for two consecutive days during the observations.

Fig. 1. Photograph of the Rayleigh and sodium lidar system.

Fig. 2. Schematic diagram of the lidar system.

Fig. 3. Atmospheric density (a), temperature (b) and sodium density (c) observed over Hefei in on July 2017.

Fig. 4. Monthly average sodium density (a), sodium column density (b), centroid height (c) and RMS width (d) observed over Hefei during 2017.

Fig. 5. Extinction coefficient observed by the sodium channel at night on 29 October 2017 (a) and 30 October 2017 (b), respectively.