Quality Analysis Of GPS Occultation Inversion Profile And Atmospheric Boundary Layer Inversion Study

Traditional atmospheric detection systems are susceptible to external factors,and detection data in special regions such as plateau ocean polar regions are very scarce.However,GPS radio occultation technology,as an emerging means of detecting the earth's atmosphere,has the advantages of all-weather observation,high self-correcting detection accuracy,low cost,long-term stability,high vertical resolution,and global coverage.The technology is of great significance for high-precision prediction of numerical weather and research on space climate change.This article elaborates the detection principle,error source and inversion algorithm of GPS radio occultation technology in detail.It collects the occultation profile data provided by the National Satellite Meteorological Center and CDAAC.The IGRA sounding data set provided by the global station was used to perform spatiotemporal matching.The quality of occultation profile data of different types,different latitudes and different seasons was analyzed.After verifying the scientificity of the occultation technology,the characteristics of the temporal variation and spatial distribution of the global boundary layer height were discussed in depth using China's FY3 C occultation index profile data.The main research contents and conclusions of this article are as follows:(1)By comparing and analyzing the error characteristics of exploration data from different occultation plans in the same period.The results show that:COSMIC,KOMPAST5,MetOp-A,MetOp-B,PAZ and TSX have not much different mean occultation deviations,and the statistics F=0.9857> 0.05,which can reject the original hypothesis.That is,there is no significant difference in the deviation of different occultation data.The detection accuracy of GPS occultation inversion profile data is not affected by the occultation task.In addition,no matter what type of occultation plan,the temperature deviation of the wet temperature profile data is negative,and the total average deviation varies from-0.1 to-0.5 K.The occultation data has a negative deviation of less than 0.4 K in absolute value relative to the IGRA radiosonde data,that is,the occultation technology detection data is comparable to the traditional sounding station detection accuracy.(2)To investigate the influence of latitude and seasonal changes on the quality from the COSMIC occultation inversion profile.The results show that the statistic corresponding to the seasonal change factor F=0.9996> 0.05.It shows that there is no significant difference between the seasonal variation and the average deviation of temperature,that is,the quality of the COSMIC wet temperature profile data is notaffected by the seasonal factors;the statistic of the latitudinal variation factors is F=0.0244< 0.05.It shows that the change factor of the latitude band is significantly different from the average deviation of temperature,that is,the data quality of the COSMIC wet temperature profile is affected by the change of the latitude band factor.In particular,the peak of the average temperature deviation is located in the tropics,followed by the southern cold zone in the southern hemisphere,which is mainly caused by the influence of the abundant water vapor in the EQU and SHH regions.However,the global average temperature deviation is-0.1628 K,which is lower than0.2 K overall,and the quality of the wet temperature profile and sounding accuracy of COSMIC occultation inversion are comparable.(3)The effect from different matching standards on the inversion profile quality of GPS occultation is explored.The results show that the statistics F=0.412> 0.05 and the spatial distance difference F=0.974> 0.05 are both acceptable for the original hypothesis.It shows that there is no significant difference between the change of matching criteria and the mean deviation of GPS occultation data,that is,the quality of the refractive index profile of GPS radio occultation is not affected by the change of matching criteria.In addition,the global average temperature deviation of FY3 C does not exceed 0.15 K,the average deviation of refractive index is less than 1%,and the average deviation of specific humidity profile is less than 0.1 g / kg.Global FY3 C occultation data accuracy is consistent with IGRA sounding station data,the quality of GPS occultation inversion profile is comparable to traditional sounding accuracy.(4)In view of the scientific nature of the occultation technique,China 's FY3 C occultation data is used to study the height characteristics of the boundary layer.The results show that the global average boundary layer height is mainly concentrated from the surface to the height of 2 km.It is roughly estimated that it accounts for about 70% of the total number of samples.The statistical frequency of the height of each boundary layer below 2 km exceeds 5%.From the perspective of spatial distribution characteristics,the average boundary layer height in marine areas is significantly smaller than that in land areas.From the perspective of time change characteristics,with the increase of the month,the average boundary layer height of the atmosphere in the northern and southern hemispheres exhibits a change trend of "two peaks and one valley".