Abstract
Based on application of the atomic filter technology in a signal detection system of lidar, the diurnal observation of sodium lidar were obtained using the system at the National Space Science Center of the Chinese Academy of Sciences at Beijing Yanqing station (40.5° N, 116° E) in April 2014. During the lidar observation period, among the 103 cases of continuous daytime observations, the longest time was 181 h. In the case of a continuous observation period of 5 days (13–18 October 2014), the signal-to-noise ratio reached to 19:1 at 12:00–13:00 Local Time of the daytime, when the spatial and time resolutions were respectively set to 96 m of 167 s. The improvements resulted in the highest detection level of any existing diurnal lidars in China. Some interesting phenomena such as the sporadic sodium layer have also been observed during the daytime. The daytime capability extended the observing time range of the earlier systems that were limited to only nighttime observations. This innovation provides a useful method for the studies of diurnal tides, photochemistry, gravity waves, and correlative modeling studies.
Highlights
Between 80 and 110 km, there is a metal atom layer including sodium, potassium, and calcium, among which sodium lidar has been widely developed due to the sodium atomic high density on the one hand, and on the other its high resonance fluorescence efficiency [1,2,3,4,5]
In the diurnal sodium diurnal sodium fluorescence lidar system at Yanqing, two identical Faraday anomalous dispersion filter technology (FADOF) are used in the receiving channel to to receive receive variousatpolarization polarization components in the the back-scattered back-scattered photon signal, respectively, fluorescence lidar system
We removed the absorber and opened both channels; the voltage was nearly twice that of a single channel. These results show that the two polarization components of the signal light can pass through the dual-channel FADOF at the same time, and the improvement of efficiency of dual-channel FADOF
Summary
Between 80 and 110 km, there is a metal atom layer including sodium, potassium, and calcium, among which sodium lidar has been widely developed due to the sodium atomic high density on the one hand, and on the other its high resonance fluorescence efficiency [1,2,3,4,5]. In 1991, a new method based on atomic Faraday anomalous dispersion filter technology (FADOF) was developed [16] Effective transmission of this atomic resonance filter is greatly improved, along with higher stability and ultra narrow band characteristics. A series of atomic filters and discriminators for different materials and wavelengths have been developed [24,25] They have advantages of narrow transmission band, high out-of-band suppression ratio, stable transmission characteristics, wide field-of-view and high transmission rate. These atomic filters and discriminators have been employed in laser communication, Doppler wind lidar [26], chromatography of the sun [27], and solar magnetic field and velocity field [28]. Under good weather conditions, continuous observations are possible throughout the day, with the longest data sets up to 7 days, which improve our current understanding of the middle and upper atmosphere
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
