Influence of thermospheric effects of solar activity on the middle atmosphere circulation and stationary planetary waves

Research output: Chapter in Book/Report/Conference proceedingOther chapter contributionResearch

Abstract

Atmospheric large-scale disturbances, for instance planetary waves, play a significant role in atmospheric general circulation, influencing its dynamical and thermal conditions. Solar activity may influence the mean temperature at altitudes above 100 km and alter conditions of wave propagation and reflection in the thermosphere. Using numerical simulations of the general atmospheric circulation during boreal winter, statistically confident evidences are obtained for the first time, demonstrating that changes in the solar activity (SA) in the thermosphere at heights above 100 km can influence propagation and reflection conditions for stationary planetary waves (SPWs) and can modify the middle atmosphere circulation below 100 km. A numerical mechanistic model simulating atmospheric circulation and SPWs at heights 0 – 300 km is used. To achieve sufficient statistical confidence, 80 pairs of 15-day intervals were extracted from an ensemble of 16 pairs of model runs corresponding to low and high SA. Results averaged over these intervals show that impacts of SA above 100 km change the mean zonal wind and temperature up to 10% at altitudes below 100 km. The statistically confident changes in SPW amplitudes due to SA impacts above 100 km reach up to 50% in the thermosphere and 10 – 15% in the middle atmosphere depending on zonal wavenumber. Changes in wave amplitudes correspond to variations of the EP-
flux and may alter dynamical and thermal SPW impacts on the mean wind and temperature.
Original languageEnglish
Title of host publicationEGUsphere
Subtitle of host publicationEGU General Assembly, Wien 3-10 May 2020
Place of PublicationWien
PublisherEuropean Geosciences Union
VolumeEGU2020
DOIs
StatePublished - 4 May 2020
EventEGU General Assembly 2020 - General Assembly , Vienna, Austria
Duration: 3 May 20208 May 2020

Conference

ConferenceEGU General Assembly 2020
CountryAustria
CityVienna
Period3/05/208/05/20

Scopus subject areas

  • Atmospheric Science

Keywords

  • thermosphere
  • Solar activity
  • circulation
  • MIDDLE ATMOSPHERE
  • modeling

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