Wind filtering evidence of mesospheric short-period gravity waves
revealed from all-sky images at King Sejong Station (62{degree sign}S,
59{degree sign}W)
Abstract
We analyzed OH airglow images observed from an all-sky camera at King
Sejong Station, Antarctica for the period of 2012–2016. Using
M-transform method, 2D-power spectra of short period waves (<
1 hr) were obtained from 107 image sequences. The power spectral
densities evidently show that the mesospheric wave activity is the
strongest during winter. We also constructed climatological wind
blocking diagrams using horizontal winds obtained from MERRA-2 for the
altitudes of = 10–64 km, and from KSS meteor radar data for = 80–90
km. The wind blocking diagrams are negatively matched with the dominant
propagating directions of the observed slow speed waves (< 30
m/s), providing the graphical evidence of wind filtering effects.
However, there are significant eastward waves in winter and strong
south-eastward waves in spring that are not blocked by the stratospheric
winds. We speculate that these waves may be generated from the upper
stratosphere or mesosphere.