Meteor radar observations on the enhancement of the high-latitude mesospheric semidiurnal tides during August and September

This study examines the inter annual fluctuations of mesospheric semidiurnal tides (SDT) using wind data from a meteor radar. Observations from the Chatanika station (65°N, -147°E) between 2018 and 2022 are analyzed. It is noted that during August–September of each year, the SDT amplitudes at this location are notably higher. This trend correlates with the low-latitude stratospheric quasi-biennial oscillation (QBO), as determined from model data and other observations. Specifically, during years with eastward QBO winds at 50 hPa (QBOe), SDT amplitudes exceed the average levels. The variations in SDT amplitudes during the August–September period seem to align with the QBO wind direction, suggesting a modulation effect.