講演情報
[PEM20-04]Data Assimilation of the Meteor Radar Wind Observations in the Mesosphere and Lower Thermosphere
*Dai Koshin1、Kaoru Sato2、Jorge L. Chau3、J. Federico Conte3、Mani Sivakandan3、David Fritts4、Njål Gulbrandsen5、Masaki Tsutsumi6、Satonori Nozawa7、Christoph Jacobi8、Alan Liu9、Nicholas Mitchell10、Johan Kero11、Toralf Renkwitz3、Danny Scipion12、Kenneth Obenberger13、Ralph Latteck3、Rodolfo Rodriguez14、Alexander Kozlovsky15、S. Vijaya Bhaskara Rao16、M. Venkat Ratnam17、Pedrina Terra18、Carlos Perez18、Paulo Prado Batista19、Vania Fatima Andrioli19、Lourivaldo M. Lima20、Alexandre A Pimenta19、Damian Murphy21、Chunxiao Yan22、Maosheng He22、Wen Yi23、Guozhu Li24、Tracy Moffat-Griffin25、Neil Hindley26、Iain Reid27、Denise Thorsen28、Dmitry V. Korotyshkin29、Byeong-Gwon Song30、Hye-Yeong Chun30、Patrick Joseph Espy31、Bronwyn Dolman32、Chris Adami32 (1.High Altitude Observatory, NSF National Center for Atmospheric Research、2.Department of Earth and Planetary Science, The University of Tokyo、3.Leibniz Institute of Atmospheric Physics、4.GATS、5.The Arctic University of Norway、6.National Institute of Polar Research、7.ISEE, Nagoya University、8.Institut für Meteorologie, University of Leipzig、9.Embry-Riddle University、10.Centre for Atmospheric and Environment Research, University of Bath、11.Swedish Institute of Space Physics、12.Radio Observatorio de Jicamarca, Instituto Geofísico del Perú、13.Air Force Research Laboratory、14.Universidad de Piura、15.Sodankylä Geophysical Observatory, University of Oulu、16.Department of Physics, Sri Venkateswara University、17.National Atmospheric Research Laboratory、18.University of Central Florida、19.National Space Research Institute, INPE, São José dos Campos、20.Departamento de Física, Universidade Estadual da Paraíba、21.Climate Processes and Change, Australian Antarctic Division, Department of the Environment、22.National Space Science Center, Chinese Academy of Sciences、23.Deep Space Exploration Laboratory / School of Earth and Space Sciences, University of Science and Technology of China、24.Beijing National Observatory of Space Environment, Institute of Geology and Geophysics、25.British Antarctic Survey、26.University of Bath、27.School of Physical Sciences, University of Adelaide、28.University of Alaska Fairbanks、29.Kazan Federal University、30.Korea Polar Research Institute、31.Norwegian University of Science and Technology、32.ATRAD Pty Ltd.)
キーワード：
data assimilation、meteor radar、MLT、reanalysis
JAWARA is a data assimilation reanalysis that covers the entire middle atmosphere from the ground to the lower thermosphere (https://jawara.nipr.ac.jp). Currently, satellite temperature data from Aura MLS, TIMED SABER, and DMSP SSMIS are assimilated as observations in the mesosphere and lower thermosphere. The analysis is confirmed to show a good comparison with assimilated observations, for climatology and variations with daily to interannual timescales. However, when compared with meteor radar observations, an easterly bias is observed in the zonal wind above 90 km at least in the equatorial region. Thus, this study has an attempt to assimilate horizontal wind observations at heights of 70–110 km to improve the reanalysis winds, and evaluate the impact of wind observations. The new analysis assimilates ~40 meteor radar observations from around the world and is compared with the current version of JAWARA, which does not use meteor radar observations. The radar observations, which are given in geometric coordinates, are assimilated based on the geopotential height of the forecast model. The target period is from October 2023 to October 2024. In summary, the new analysis with meteor radar observations becomes closer to the assimilated observations at each station, which means a reduction in analysis bias. In fact, the mean and root mean square (RMS) differences between observations and analysis decrease through this assimilation. Additionally, differences in zonal mean zonal winds depending on latitude are observed. Along with the change in zonal winds, the zonal mean temperature is also modified. These results indicate an improvement in the analysis of the global dynamical field.