Research On Wind Profile Inversion Technology Of Spaceborne Doppler Asymmetric Spatial Heterodyne (DASH) Based On Globally Optimization Method

Atmospheric wind field information is very important for atmospheric scientific research,spacecraft operation safety and medium and long-term weather forecasting.The wind field profile can intuitively reflect the variation law of wind field information with height,and is one of the primary objectives of wind measurement instruments.Doppler Asymmetric Spatial Heterodyne spectrometer is a precision optical instrument designed based on the principle of double-beam equal-thickness spatial modulation interference.It has the advantages of compact structure,no moving parts,high luminous flux,and high spectral resolution,and is suitable for spaceborne high-sensitivity detection of atmospheric wind profile.The spaceborne Doppler Asymmetric Spatial Heterodyne spectrometer detects the middle and upper atmospheric wind field by measuring the change of atmospheric airglow spectral frequency to retrieve atmospheric motion information.The original interferogram directly collected by the interferometer is formed by the integration of the multi-layer atmospheric radiation along the line-of-sight direction.The wind field profile needs to be retrieved from the line-of-sight wind obtained by direct inversion.Therefore,wind profile inversion is an important link in the inversion process of sounding data.At present,the atmospheric wind profile inversion technology used by the spaceborne Doppler Asymmetric Spatial Heterodyne spectrometer is the onion peeling algorithm.The algorithm has the characteristics of simple and fast calculation process,but the characteristics of layer-by-layer calculation will cause errors to accumulate to the lower layers,resulting in lower inversion accuracy.To solve this problem,this thesis explores the feasibility of inversion of the spaceborne Doppler Asymmetric Spatial Heterodyne spectrometer wind profile based on the globally optimization method.This work has reference significance for advancing the theoretical research and practical application of spaceborne atmospheric wind detection data inversion.Firstly,this thesis introduces the composition of the globally optimization algorithm and the operation logic of each part.Combined with the technical principle of Doppler Asymmetric Spatial Heterodyne spectrometer and the spaceborne observation mode,the applicability of the globally optimization algorithm is discussed from the theoretical level,and the optimal selection of the evaluation function for wind field inversion is studied.And verified the theoretical applicability of globally optimization method for wind profile inversion of spaceborne Doppler Asymmetric Spatial Heterodyne spectrometer.Secondly,for the interferogram distortion,one of the important factors affecting the line-of-sight integral phase inversion,the sources of the interferogram distortion are analyzed and summarized,and verified the effects of four kinds of distortions,namely fringe bending,local bending,tilt,and spatial frequency variation on the line-of-sight integral phase inversion accuracy.Simulation analyzed the effect of direct phase inversion accuracy in the case of multi-row merging along the spatial direction.The results show that the Doppler phase error will increase with the increase of the target wind speed and the degree of distortion of the interferogram.The phase error caused by the local bending of the fringe is the largest,and the smaller the range of the local bending is,the larger the phase error is generated when it is closer to the sampling center.Multi-line pixel merging with distortion interferogram can effectively reduce the uncertainty of phase inversion.Therefore,even if the interferogram has local curvature,the multi-line pixel merging method can still be used to improve the wind field inversion accuracy.Thirdly,the onion peeling algorithm and the globally optimization algorithm were used to invert the wind profiles respectively based on the full-link model of the spaceborne Doppler Asymmetric Spatial Heterodyne spectrometer,using oxygen red line Level-0 data observed by Michelson Interferometer Global High-resolution Thermospheric Imaging(MIGHTI),and the inversion results were compared and verified.The difference between the two wind speeds at the same layer is within 15 m/s.The uncertainty simulation of the two wind profile inversion algorithms shows that compared with the onion peeling algorithm,the globally optimization algorithm has a better inversion effect in the range of 170-260 km,and the wind speed inversion error will not be transmitted to the bottom layer.This thesis discusses the technical feasibility of the globally optimization algorithm for inversion of the wind profile of the spaceborne Doppler Asymmetric Spatial Heterodyne spectrometer,which has certain reference significance for advancing the theoretical research of the spaceborne Doppler Asymmetric Spatial Heterodyne spectrometer data inversion.