Correction of distorted FPI interferograms to invert atmospheric winds and temperatures.

Fabry-Perot interferometer (FPI) is a vital optical device for measuring atmospheric wind and temperature, which is widely used worldwide for its simple structure and excellent accuracy. Nevertheless, the working environment of FPI could be light polluted by many factors, such as light from street lamp and moon, which results in distortion for realistic airglow interferogram and thus affects the accuracy for the wind and temperature inversion. We simulate the FPI interferogram and invert the correct wind and temperature from the full interferogram and three parts of it. Further analysis is performed using real airglow interferograms observed at Kelan (38.7°N, 111.6°E). Distortion interferograms cause temperature deviations, while the wind is not affected. A correction method is presented to correct the distortion interferogram by making it more homogeneous. The corrected interferogram is calculated again, and the result shows that the temperature deviation of the different parts is reduced significantly. Wind and temperature errors of each part are reduced compared to the previous ones. This correction method will help improve the accuracy of the FPI temperature inversion when the interferogram is distorted.

Narrowband sodium lidar for the measurements of mesopause region temperature and wind.

We report here a narrowband high-spectral resolution sodium temperature/wind lidar recently developed at the University of Science and Technology of China (USTC) in Hefei, China (31.5 °N, 117 °E). Patterned after the Colorado State University (CSU) narrowband sodium lidar with a dye laser-based transmitter, the USTC sodium temperature/wind lidar was deployed with a number of technical improvements that facilitate automation and ease of operation; these include a home constructed pulsed dye amplifier (PDA), a beam-steering system, a star-tracking program, and an electronic timing control. With the averaged power of ∼1.2 W output from PDA and the receiving telescope diameter of 0.76 m, our lidar system has a power aperture product of ∼0.55 Wm(2) and is comparable to the CSU and the University of Illinois at Urbana-Champaign (UIUC) sodium lidar systems. The uncertainties of typical measurements induced by photon noise and laser locking fluctuation for the temperature and wind with a 2 km vertical and 15 min temporal resolutions under the nighttime clear sky condition are estimated to be ∼1.0 K and ∼1.5 m/s, respectively, at the sodium peak (e.g., 91 km), and 8 K and 10 m/s, respectively, at both sodium layer edges (e.g., 81 km and 105 km). The USTC narrowband sodium lidar has been operated regularly during the night since November 2011. Using the initial data collected, we demonstrate the reliability and suitability of these high resolution and precision datasets for studying the wave perturbations in the mesopause region.