Research On All-sky Gravity Wave Imager

Tracing the airglow emission, all-sky gravity wave imagers are widely used for imaging the atmospheric gravity waves. The characters of the imager are: wide field of view, fast, high resolution, low cost. Until this work, there has never been report researching on this technique in China. Developing the airglow gravity wave imaging technique is significant to the scientific community and prospective to the applied researches in our country.The fundamental principle, the developing technique, the preprocessing procedure, and the analytical method for application of the imager are studied. The main contents can be list as follow:1. The basic theory of the gravity wave and airglow is introduced. Besides the background of the atmosphere, the gravity wave, airglow and their relation are emphasized.2. The developing technique of the hardware and software in the CSSAR gravity wave imager is researched. The basic principle and key parameters are studied, and some key techniques of the hardware and software are concluded.3. The preprocessing method is researched, including the bias correction, flat-field correction, direction correction, distortion correction and star filtering.4. The first imaging observation experiment of the atmospheric gravity waves in the mesopause region in China and the preliminary result are studied. Case studies show that the horizontal wavelengths, observed horizontal phase velocities, horizontal propagation azimuth angles and observed periods of three QMGW examples are about (12.3 km, 41 m/s, 327°, 5 min), (25 km, 35 m/s, 68°, 12 min) and (10 km,48 m/s,341°,3.5 min), respectively.5. A typical gravity wave-event was observed during the CSSAR all-sky gravity wave imager daily observation. The data of the MF radar and TIMED/SABER is co-analyzed and shows that there may be a thermal duct. The wavelength decease at 15.6km/h, and the wave front oscillates around 155°with an amplitude of 2.5°and a period of 55 min.6. The unambiguous power spectrum and angular spectrum are studied, and used for analysis the spectral characters of the gravity waves on Jan. 5th, 2009. The spectral result shows that the low limit of the wavelength is short, and the gravity waves transmit in all directions but more westly than eastly.