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Observations of mesospheric gravity waves generated by geomagnetic activity
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  • Viswanathan Lakshmi Narayanan,
  • Corwin James Wright,
  • Martin G. Mlynczak,
  • Neil P Hindley,
  • Andrew John Kavanagh,
  • Tracy Moffat-Griffin,
  • Phoebe E Noble
Viswanathan Lakshmi Narayanan
University of Bath

Corresponding Author:[email protected]

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Corwin James Wright
University of Bath
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Martin G. Mlynczak
NASA Langley Research Center
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Neil P Hindley
University of Bath
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Andrew John Kavanagh
British Antarctic Survey
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Tracy Moffat-Griffin
British Antarctic Survey
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Phoebe E Noble
University of Bath
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Abstract

Gravity waves (GWs) play an important role in the dynamics and energetics of the mesosphere. Geomagnetic activity is a known source of GWs in the upper atmosphere. However, how deep the effects of geomagnetic activity induced GWs penetrate into the mesosphere remains an open question. We use temperature measurements from the SABER/TIMED instrument between 2002 - 2018 to study the variations of mesospheric GW activity following intense geomagnetic disturbances identified by AE and Dst indices. By considering several case studies, we show for the first time that the GWs forced by geomagnetic activity can propagate down to about 80 km in the high latitude mesosphere. Only regions above 55° latitudes show a clear response. The fraction of cases in which there is an unambiguous enhancement in GW activity following the onset of geomagnetic disturbance is smaller during summer than other seasons. Only about half of the events show an unambiguous increase in GW activity during non-summer periods and about one quarter of the events in summer show an enhancement in GWs. In addition, we also find that the high latitude mesopause is seen to descend in altitude following onset of geomagnetic activity in the non-summer high latitude region.
14 Oct 2023Submitted to ESS Open Archive
17 Oct 2023Published in ESS Open Archive