Abstract
Gravity wave (GW) activities in the upper mesosphere (80–100 km) and their potential sources are investigated using meteor radar observations at King Sejong Station, Antarctica (KSS; 62.22°S, 58.78°W) during recent 14 years (2007–2020). GW activities are estimated by horizontal wind variances of small-scale GWs (periods <2 h, horizontal wavelength <400 km, or vertical wavelength <3–5 km). The wind variances show clear semiannual variations with maxima at solstices, and annual variations are also seen above z = 90 km. The deseasonalized wind variances at z = 96.8 km have a statistically significant periodicity of ∼11 years that can be associated with solar cycle variations. Three major potential GW sources in the lower atmosphere are examined. Orography is a potential source of GWs in winter and autumn, when the basic-state wind is westerly from the surface up to the mesosphere. The residual of the nonlinear balance equation (RNBE) at 5 hPa, a diagnostic of the GWs associated with jet stream, is the largest in winter and has a secondary maximum in spring. The correlation between the observed GWs and RNBE is significant in equinoxes, while correlation is low in winter. Deep convection in storm tracks is a potential source in autumn and winter. Secondary GWs generated in the mesosphere can also be observed in the upper mesosphere. Ray-tracing analysis for airglow images observed at KSS indicates that secondary GWs are mostly generated in winter mesosphere, which may be associated with the breaking of orographic GWs.
Original language | English |
---|---|
Article number | e2021JD034528 |
Number of pages | 22 |
Journal | Journal of Geophysical Research: Atmospheres |
Volume | 126 |
Issue number | 10 |
Early online date | 4 May 2021 |
DOIs | |
Publication status | Published - 27 May 2021 |
Bibliographical note
Funding Information:This work was supported by Korea Polar Research Institute (KOPRI, PE19020/PE20100/PE21020). The authors would like to thank to two anonymous reviewers and the editor for their valuable comments and suggestions.
Data Availability Statement
The raw data of the meteor radar and all-sky airglow imager at King Sejong Station are available from Korea Polar Data Center (KPDC) (https://kpdc.kopri.re.kr/). The meteor radar observational data at Rothera station are available at http://psddb.nerc-bas.ac.uk/data/access/. The MERRA-2 data set was obtained from https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/data_access/. The ERA-Interim data are available through http://apps.ecmwf.int. The CIRA data are available at http://data.ceda.ac.uk/badc/cira/data/. The NCEP CFSR data are available at https://rda.ucar.edu/datasets/ds093.0/. The FORTRAN program for the HWM14 data is available at https://doi.org/10.1002/2014EA000089.
Funding
This work was supported by Korea Polar Research Institute (KOPRI, PE19020/PE20100/PE21020). The authors would like to thank to two anonymous reviewers and the editor for their valuable comments and suggestions.
Keywords
- Antarctica
- gravity waves
- meteor radar
- MLT
- upper mesosphere
ASJC Scopus subject areas
- Atmospheric Science
- Geophysics
- Earth and Planetary Sciences (miscellaneous)
- Space and Planetary Science