Analysis And Research Of Atmospheric Sounding Data In Near Space

The near space is located between the aircraft flight altitude and the orbital aircraft flight altitude,and is an indispensable intermediate platform for air and space integration operations.It has an important strategic position and unique military application value.There are also significant changes in atmospheric temperature,density,and wind field in the near space.These changes have important influence on the flights of near space vehicles,such as stratospheric airships and hypersonic vehicles.Therefore,the development and application of near space vehicles have an urgent need for corresponding near space weather protection.The analysis and application of near space atmospheric sounding data is an important part of the near space weather protection system.According to the current research status and existing problems of satellite remote sensing technology and falling sphere technology,this paper mainly studied four issues including the error analysis of remote sensing data,the variational fusion of multi-source satellite remote sensing data,the correction of residual ionospheric errors in radio occultation,and the key techniques of data processing in falling-sphere sounding.The specific contents are summarized as follows:（i）The temperature errors of the SABER observation data and the COSMIC observation data were analyzed,which can provide the error basis for the variational fusion of multi-source satellite observation data in near space.First,the high precision of the two satellite observation data below 32 km was verified by comparing with the high-resolution radiosonde data.Secondly,the COSMIC observation data and the SABER observation data were compared with each other,and the results revealed that the temperature variations of these two sets of satellite data were generally consistent,and the temperature deviations between these two sets of data vary with heights,latitudes,and seasons.Finally,the temperature error matrixs of the COSMIC observation data and the SABER observation data were calculated using the temperature deviations between the two sets of data and the refraction errors of COSMIC radio occultations.The calculation results showed that the temperature errors of COSMIC observation data increase with heights,the temperature errors in the lower stratosphere are about 0.5 K.At height of 40 km,the temperature errors are mostly larger than 3.5 K with a maximum error of 5.5 K.The SABER observation data has high detection accuracy in the stratosphere,the temperature errors are mostly within a range between 0 K and 3.5 K,and the errors are less than 1 K at height of 40 km.（ii）The variational fusion of COSMIC observation data and SABER observation data,comblining the kriging interpolation method,was processed to obtain a global atmospheric temperature field within a height range from 15 km to 40 km.The error covariance matrixs were obtained from the statistic results of temperature error in Chapter 3.The cross-contrast results showed that the temperature field after variational fusion was more consistent with the temperature field of COSMIC within the height range of 15 km to 35 km,the mean temperature deviations between this two were between-1 K and 1 K,and the standard deviations were within a range from 3 K to 4 K.The variational fusion temperature was more consistent with SABER temperature at heights between 35 km and 40 km,the mean temperature deviations were in the range of 0 K to 0.5 K,and the standard deviations were between 1.8 K and 2 K.The temperature field after variation fusion was a good combination of the high precision observation data of SABER at heights near 40 km and the high precision observation data of COSMIC within the height range of 15 km to 30 km.（iii）The NRLMSISE-00 neutral atmospheric empirical mode and Ne-Quick ionospheric mode were used to provide the atmospheric background,then a model for simulating the bending angles in radio occultation and their residual ionospheric errors was established based on the Abel integral equation.The simulating results showed that the residual ionospheric errors increase with height gradually,and the residual ionospheric errors were closely related to ionospheric electron density profiles.For futhur study,this model was used to validate the new ionospheric correction method proposed by Healy and Culverwell（2015）.A new term,κ（a）(α_L1（a）-α_L2（a）)²,was added in the original method of dual-frequency bending angles linear combination to weaken the residual ionospheric errors.In this paper,the new ionospheric correction method was improved by characterizing the varitions ofκvalues with different local time,different latitudes,different altitudes,and different solar activity levels.The simulation results showed that the improved ionospheric correction method can better eliminate residual ionospheric erros.While the modeledκvalues were applied in the bending angle ionospheric correction,the simulated residual ionospheric errors of the bending angles decreased from approximately 5×10^-8 rad to 1×10^-9 rad during daytime,in the latitude of 40°N,and with the solar activity level of F_10.7=210.（iv）The key technologies in the data processing of meteorological rocket falling-sphere sounding were studied,including the calculation method of drag coefficient and the calculation method of atmospheric temperature.The method to calculate the atmospheric temperature profile using the atmosphere density profile was studied,and the systematic error of the calculating method was statistical analyzed.The atmospheric parameter inversion system of meteorological rocket falling-sphere sounding was completely established and the falling-sphere flight data from one test was used to verify this inversion system.The result showed that the atmospheric parameter inversion system was effective and reliable,and the wind field data obtained through inversion of flight data is accurate.Due to the uncertainty of drag coefficient,there were certain errors in the calculation results of atmospheric density and atmospheric temperature.