Data Assimilation Study In Near Space Based On Whole Atmosphere Community Climate Model And Data Assimilation Research Test-Bed

Near space has already been increasingly brought to the front of world's major military powers' attention due to its huge strategic value.Carrying out research on technology and method of forecasting and analysing near space atmospheric and environmental states has become a hot issue in the research and application fields of near space,whose scientific and military apllication value bacome increasingly outstanding.This study is mainly based on Whole Atmosphere Community Climate Model(WACCM)which includes high-middle atmopsheric dynamics and chemical processes.From the perspective of optimizing initial condition,this study performs middle-high atmospheric observations assimilation tests based on near space assimilating and forecasting system,WACCM and Data Assimilation Research Test-Bed(WACCM+DART),aiming to improve WACCM's perfomance of forecasting near space atmospheric states and provide reference and support for developing our army's near space atmospheric analysis and forecasting operation.This study mainly include the following three parts.This study firstly utilizes ECMWF's recent released fifth generation reanalysis-ERA5,which has already extended to near space,to construct initial condition(IC)for WACCM and evaluate the forecast skill of constructed IC and WACCM's default climatic IC in representing a stratosphere sudden warming event.The assessment of forecast skill indicates that the simulation using WACCM's default climatic IC can not well represent drastic change of zonal wind and temperature in near space during the SSW event in 2016.On the contrary,the evolution characteristics of zonal wind and temperature from lower stratosphere to middle mesosphere in future 4-5d simulated by the tests using the constructed IC by ERA5 show good consistency with that of ERA5 reanalysis.Secondly,this study performs SABER and MLS temperature observations assimilating tests based on near space assimilating and forecasting system-WACCM+DART,to evaluate the impact of assimilating SABER and MLS temperature observations on the analysis and forecasting effect of temperature and wind in near space.Study indicates that assimilating SABER and MLS temperature observations can not only significantly reduce temperature forecasting and analysis error in near space,but also minish zonal wind analysis error in stratosphere and lower mesosphereabove northern high latitudes.Furthermore,assimilating lower atmospheric observations also leads a positive impact on reducing zonal wind analysis bias,however its impact is not as significant as that of assimilating SABER and MLS temperature data.Lastly,this study adds interface programs for assimilation SABER and MLS ozone data in the near space data assimilation and forecasting system-WACCM+DART and performs SABER and MLS ozone data assimilating tests to simulate a stratosphere sudden warming(SSW)event during February 2016.Following findings are obtained: the ozone analysis produced by SABER and MLS ozone data assimilation can well represent the sudden variation of stratospheric ozone profile above north polar area during SSW,which shows good agreement in describing ozone changing characteristics with ERA5 reanalysis;the 6 hour ozone forecast verification shows that the improvement of 6 hour ozone forecast through assimilating SABER and MLS ozone data is obviously reflected in upper stratosphere-lower mesosphere and middle stratosphere respectively;assimilating ozone observations pronouncedly reduces analysis error of temperature and zonal wind in stratosphere and lower mesosphere above middle-high latitude area;verification of 0-10 d ozone forecast shows that adding SABER and MLS ozone data assimilation in WACCM+DART can better improve 0-10 d ozone forecasting result of WACCM in lower stratosphere and lower mesosphere relative to control test.