Study of solar cycle dependence of the quasi-two-day wave in the MLT from an extratropical station

Abstract

The relationship between the quasi-two-day wave (QTDW) and solar variability during summer in the MLT is studied using long-term meteor wind observations from an extratropical station, Cachoeira Paulista (22.7°S, 45°W) in the Southern hemisphere. Overall, the seasonal (summer) mean and monthly mean zonal amplitude of the QTDW show a negative correlation and the meridional amplitude exhibits a positive correlation with the solar F10.7 flux in the MLT. Although the seasonal mean (summer) wave period shows positive correlation with the solar cycle, both positive and negative correlations are found in the monthly mean period in certain summer months at the present location. Additionally, both amplitude and period of the QTDW show slightly higher values in solar minimum and lower values in solar maximum within the limit of standard deviation indicating a weak, but measurable response to the solar cycle. The features of the present study bearing similarity as well as disagreement with the findings of the past investigators are also discussed in the perspective of current understanding.