Research On 760nm Lidar For Atmospheric Pressure Measurement

Atmospheric pressure refers to the weight of the entire air column from the observed height to the upper boundary of the atmosphere per unit area.It is an extremely important physical quantity in meteorology.Its distribution and changes are closely related to atmospheric movement and weather conditions,basically all atmospheres.Pressure parameters are required for the model.In the application of related meteorological fields such as global numerical weather prediction and climate change research,there is a high requirement for the accuracy of surface atmospheric pressure data.The International Meteorological Organization proposes that in order to meet the requirements of global numerical weather prediction,the global surface atmospheric pressure measurement is not The degree of certainty(1? accuracy)is less than 0.1%,and the horizontal resolution is not greater than 500 km.Lidar technology is a technology that can be used for remote sensing of atmospheric pressure in the world.It can effectively obtain meteorological data with high spatial and temporal resolution.It can be used on airborne or spaceborne platforms to detect atmospheric pressure.This thesis uses Lidar technology to carry out the research work of atmospheric pressure detection,which has good scientific exploration and application prospects.The volume ratio of oxygen in dry air is fixed at 20.95%,and in the oxygen absorption band of oxygen,oxygen is the only absorption gas in the atmosphere,so the absorption characteristics of oxygen absorption band can be applied to pressure detection.Firstly,the paper calculates the calculation model of the absorption line of oxygen absorption band and analyzes the temperature-pressure sensitivity of the line.Since the object to be detected is atmospheric,the detection wavelength of the lidar is selected in the range where the absorption line is insensitive to temperature.Then an inversion algorithm for detecting surface pressure using spaceborne integrated path differential absorption(IPDA)lidar is proposed.This method establishes the relationship between the differential absorption optical depth and the corresponding atmospheric pressure through empirical data,and uses the differential absorption optical depth data detected by the lidar.The method of checking the table is inversely strong.By establishing the simulation model of spaceborne lidar and the large-temperature and wet-pressure simulation model,the influence of various lidar parameters on the detection performance and the error introduced by the algorithm itself are evaluated.The appropriate detection wavelength pair is selected by calculating the error of the lidar surface pressure detected by the different detection wavelengths.In the case of selecting the detection wavelength,it is found that the error of the final lidar detection is within our requirements.Finally,the experimental data is processed.Since the system receives the atmospheric scattering echo,its signal-to-noise ratio is not high,and it is necessary to increase the signal-to-noise ratio through time accumulation.The paper compares three cumulative averaging methods and selects the best performance as a data processing tool.Then,through the established pressure inversion algorithm,the high-precision and high-time resolution pressure data of a certain height in Shanghai is obtained.The random error of pressure detection at a time resolution of 5 min and a height of 2000 m is smaller than.