EGUsphere EGUsphere EGUsphere EGUsphere 1680-7375 Copernicus Publications Göttingen, Germany 10.5194/egusphere-2024-1792 Effects of Nonmigrating Diurnal Tides on the Na Layer in the Mesosphere and Lower Thermosphere Wu Jianfei https://orcid.org/0000-0002-3998-9296 1 2 3 Feng Wuhu https://orcid.org/0000-0002-9907-9120 4 5 Xue Xianghui https://orcid.org/0000-0002-4541-9900 1 2 3 6 Marsh Daniel R. https://orcid.org/0000-0001-6699-494X 4 Plane John Maurice Campbell https://orcid.org/0000-0003-3648-6893 4 CAS Key Laboratory of Geospace Environment, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China Mengcheng National Geophysical Observatory, School of Earth and Space Sciences, University of Science and Technology of China, Hefei, China CAS Center for Excellence in Comparative Planetology, China School of Chemistry, University of Leeds, Leeds, UK National Centre for Atmospheric Science, University of Leeds, Leeds, UK Collaborative Innovation Center of Astronautical Science and Technology, 230026, Hefei, China 19 07 2024 2024 1 14 Copyright: © 2024 Jianfei Wu et al. 2024 This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/ This article is available from https://egusphere.copernicus.org/preprints/2024/egusphere-2024-1792/ The full text article is available as a PDF file from https://egusphere.copernicus.org/preprints/2024/egusphere-2024-1792/egusphere-2024-1792.pdf

The influence of nonmigrating diurnal tides on Na layer variability in the mesosphere and lower thermosphere regions is investigated for the first time using data from the Optical Spectrograph and InfraRed Imaging System (OSIRIS) on the Odin satellite and Specified-Dynamic Whole Atmosphere Community Climate Model (SD-WACCM) with metal chemistry. The Na density from OSIRIS exhibits a clear longitudinal variation indicative of the presence of tidal components. Similar variability is seen in the SD-WACCM result. Analysis shows a significant relationship between the nonmigrating diurnal tides in Na density and the corresponding temperature tidal signal. Below 90 km, the three nonmigrating diurnal tidal components in Na density show a significant positive correlation with the temperature tides. Conversely, the phase mainly indicates a negative correlation above 95 km. Around the metal layer peak, the response of the Na density to a 1 K change in tidal temperature is estimated to be 120 cm<sup>-3</sup>.

 National Key Research and Development Program of China 2022YFF0503703 National Natural Science Foundation of China 42125402 42188101 42374183 42074181 Chinese Academy of Sciences YSBR-018 Central Universities in China WK3420000020 Natural Environment Research Council NE/T006749/1