Key Points:Features of seasonal variations in the 6DWs are significant, and these seasonal features are slightly different in the mid-low latitudes qThe annual oscillations of the 6DWs in the mid-low latitudes are modulated by the quasi-biennial oscillation in the diurnal tide, resulting in seasonal features that are different from those at other latitudes q The 6DW amplitudes at mid-high latitudes has a significant 27-day solar rotation variation. q Citation: Wang, J. Y., Yi, W., Chen, T. D., and Xue, X. H. (2020). Quasi-6-day waves in the mesosphere and lower thermosphere region and their possible coupling with the QBO and solar 27-day rotation. Earth Planet. Phys., 4(3), 285-295. http://doi.Abstract: By using atmospheric wind data in the mesopause and lower thermosphere (MLT) region, features of seasonal variations in the quasi-6-day wave (6DW) at different latitudes are analyzed, and modulation of the 6DW by the diurnal tide and solar 27-day period is discussed. The data used in the analysis are extracted from a wind dataset collected by a meteor radar chain from December 2008 to November 2017. The meteor radar chain includes four stations, in Mohe, Beijing, Wuhan, and Sanya. Features of seasonal variations in the 6DW indicate that in summer the 6DW is usually strongest during July and August, followed by stronger variations in January and April.At certain altitudes over Wuhan and Sanya, the 6DW is slightly different in different years and altitudes. In our analysis of seasonal variations in the 6DW, we find that it is generally affected by annual oscillations and semiannual oscillations. The annual oscillations of the 6DW in the mid-low latitudes are modulated by the quasibiennial oscillation in the diurnal tide, resulting in seasonal features that are different from those at other latitudes. In addition, the 6DW amplitude at mid-high latitudes has a significant 27-day solar rotation variation, which was prominent in 2016.
We present the migrating tidal winds decomposed jointly from multiple meteor radars in four longitudinal sectors situated in the equatorial mesosphere and lower thermosphere. The radars are located in Cariri, Brazil (7.4°S, 36.5°W), Kototabang, Indonesia (0.2°S, 100.3°E), Ascension Island, United Kingdom (7.9° S, 14.4° W), and Darwin, Australia (12.3°S, 130.8°E). Harmonic analysis was used to obtain amplitudes and phases for diurnal and semidiurnal solar migrating tides between 82 and 98 km altitude during the period 2005–2008. To verify the reliability of the tidal components calculated by the four meteor radar wind measurements, we also present a similar analysis for the Whole Atmosphere Community Climate Model winds, which suggests that the migrating tides are well observed by the four different radars. The tides include the important tidal components of diurnal westward‐propagating zonal wavenumber 1 and semidiurnal westward‐propagating zonal wavenumber 2. In addition, the results based on observations were compared with the Climatological Tidal Model of the Thermosphere (CTMT). In general, in terms of climatic features, our results for the major components of migrating tides are qualitatively consistent with the CTMT models derived from satellite data. In addition, the tidal amplitudes are unusually stronger in January–February 2006. This result is probably because tides were enhanced by the 2006 Northern Hemisphere stratospheric sudden warming event.
<p>We present the migrating tidal winds decomposed jointly from multiple meteor radars in four longitudinal sectors situated in the equatorial mesosphere and lower thermosphere. The radars are located in Cariri, Brazil (7.4&#176;S, 36.5&#176;W), Kototabang, Indonesia (0.2&#176;S, 100.3&#176;E), Ascension Island, United Kingdom (7.9&#176; S, 14.4&#176;W), and Darwin, Australia (12.3&#176;S, 130.8&#176;E). Harmonic analysis was used to obtain amplitudes and phases for diurnal and semidiurnal solar migrating tides between 82 and 98 km altitude during the period 2005&#8211;2008. To verify the reliability of the tidal components calculated by the four meteor radar wind measurements, we also present a similar analysis for the Whole Atmosphere Community Climate Model winds, which suggests that the migrating tides are well observed by the four different radars. The tides include the important tidal components of diurnal westward-propagating zonal wavenumber 1 and semidiurnal westward-propagating zonal wavenumber 2. In addition, the results based on observations were compared with the Climatological Tidal Model of the Thermosphere (CTMT). In general, in terms of climatic features, our results for the major components of migrating tides are qualitatively consistent with the CTMT models derived from satellite data. In addition, the tidal amplitudes are unusually stronger in January&#8211;February 2006. This result is probably because tides were enhanced by the 2006 Northern Hemisphere stratospheric sudden warming event.</p>
The atmospheric winds and waves in the mesosphere and lower thermosphere (MLT) region are essential for studying the dynamics and climate in the middle and upper atmosphere. The University of Science and Technology of China (USTC) meteor radar located at Mengcheng (33.36°N, 116.49°E) has been operating continuously since April 2014. More than 8 years of observation of mesospheric horizontal winds and tides are presented in this study. In addition, we present an intercomparison among the meteor radar observations and the Navy Global Environmental Model-High Altitude (NAVGEM-HA) analysis results. The meteor number at northern lower midlatitudes suffers from diurnal variations in meteor occurrence, with a high count rate in the local morning and a low rate during local afternoon-to-midnight. The meteor count rates show a clear annual variation, with a maximum in September–October and a minimum in February. The horizontal wind in the MLT region has dominant annual variations at lower midlatitudes, with the eastward wind during summer and the westward wind during winter above 84 km, and the eastward wind during winter and the westward wind during spring below 84 km. The meridional wind is northward during winter and southward during summer. The diurnal amplitude is dominant, followed by the semidiurnal tides at lower midlatitudes. The zonal and meridional diurnal tides show enhancements during spring (March) with amplitudes that can reach up to 40 m/s and 30 m/s and during autumn (September) with amplitudes that can reach up to 30 m/s and 25 m/s, respectively. The seasonal variations in diurnal tidal amplitude basically show characteristics that are strong during the equinox and weak during the solstice. The zonal and meridional semidiurnal tides are maximized during spring (April) and autumn (September) above 90 km.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.