The Principle Of Sodium Wind/Temperature Lidar And The Method Of Data Processing

The sodium wind/temperature lidar is one of the most powerful and advanced facilities measuring the atmospheric winds and temperatures and sodium number densities within 75km and 110km altitudes. The lidar winds and temperatures are retrieved with the received resonance fluorescence scattering photon echoes from the tracer of Na atoms in the mesopause region. The lidar principle and the retrieval method of atmospheric parameters have been investigated, and its error analysis has been completes.Simulations of the lidar echoes are used to give an insight into the characters of the echo photon counts which can be used to develop the retrieval method. While the background temperature and density of atmosphere is given by atmospheric model NRLMSISE-00, and background wind is given by HWM93 model, and the Na number density profile of the sodium layer is given with a Gaussian model, the profile of echo-photon counts can be simulated by using the lidar equations of Rayleigh scattering and sodium resonance fluorescence scattering. The retrieval method of three-frequency Doppler technique is developed and applied in the data processing of the simulated echo photon counts. Their retrieved winds and temperatures agree well with the background temperatures and winds, which shows that the retrieval method is reliable. The influences of pulse accumulated effect of the photomultiplier tube in the course of photon counting and absorptions of the sodium layer on the retrievals are analyzed. Their correction methods are also provided. These methods are applied in the data processing of University of Illinois at Urbana and Champaign (UIUC) Na wind/temperature lidar. The retrieval results agree well with the results of UIUC, which show efficiencies of the correction methods.The error analysis shows sensitivities of the retrievals to laser frequency shift and linewidth variation. The precision of the measurements are given through error analysis, which suggests that this lidar has high quality measurements.The above results provide the theory and algorithm for the independent development of a new sodium wind/temperature lidar and its data processing software in China.