Ionospheric Correction Of Atmospheric Parameter Inversion Based On Quality Analysis Of Occultation Data

Radio occultation atmospheric sounding technology has the advantages of high resolution,high accuracy,low cost and global coverage.At present,it has become an important means of atmospheric sounding.In the inversion of neutral atmospheric parameters,the ionosphere has a great influence on the inversion accuracy.It is important to make effective ionospheric corrections and improve ionospheric residual errors.In order to explore the influence of ionosphere on occultation atmospheric sounding,after comparison with the reanalysis data and radiosonde data,we can find that the atmospheric parameters obtained from the inversion have high accuracy.At 10~30km,the average relative deviation of COSMIC occultation data's wet temperature is less than 0.5%,and the mean relative deviation of refractive index is less than 0.3% in general.But the mean relative deviation and standard deviation of temperature are larger in the lower troposphere;the mean relative deviation and standard deviation of refractive index are larger in the upper stratosphere.The quality of the occultation data at low latitudes near the equator is worse than high latitude regions of the two hemispheres.In the same region,the quality of the occultation data in winter and summer is worse than that in spring and autumn.The above results show that the error of atmospheric detection is mainly in the lower troposphere and upper stratosphere,the low troposphere is mainly affected by water vapor and the upper stratosphere is mainly affected by the ionosphere,the inversion accuracy of upper stratosphere atmospheric parameters is worse when the ionospheric electron density is larger.The comparison of different ionospheric correction methods shows that the bending angle ionospheric correction method is better than the phase correction method,but the error of atmospheric parameter inversion increases with altitude,shows that there is still residual error.In order to correct the ionospheric residual error,the bending angle error obtained from the comparison of the occultation data and the MSIS data shows that the ionospheric residual error is systematic bias in the upper stratosphere.The systematic deviation of the ionosphere residual can be improved by using the annual average bending angle error data.