Infrasound from tropospheric sources: Impact on mesopause temperature?

Abstract

Three- to six-day oscillations in the mesopause temperature have been observed all over the year. While these oscillations can be explained by planetary wave activity in wintertime, their summertime appearance is still under discussion. One effect possibly contributing to such summertime oscillations in the mesopause is acoustic heating. Infrasound generated by low-pressure areas or thunderstorm cells propagates into the upper atmosphere and deposits heat in this region. It is speculated that the oftentimes about weekly variation of low-pressure areas due to troposphere planetary wave activity is a potential source mechanism for mesopause temperature oscillations through infrasound as a transporting mechanism. The modeling structure of infrasound propagation as well as of acoustic heating is presented. It leads to the quantification of expected temperature fluctuations and acoustic heating rates at the mesopause height, which both appear to be too small to give a sole explanation for the 3–6-day oscillation.