STATISTICALLY SIGNIFICANT ESTIMATES OF INFLUENCE OF SOLAR ACTIVITY ON PLANETARY WAVES IN THE MIDDLE ATMOSPHERE OF THE NORTHERN HEMISPHERE AS DERIVED FROM MUAM MODEL DATA

Numerical simulation has been used to examine the effect of changes in solar activity (SA) in the thermosphere on amplitudes of long-period planetary waves (PW) for the winter period in the Northern Hemisphere. The model of the middle and upper atmosphere (MUAM) is used. It allows simulations of general atmospheric circulation at altitudes 0–300 km. In order to reproduce SA changes, different values of the solar radio flux at a wavelength of 10.7 cm at an altitude of more than 100 km are set in the MUAM radiation block. To take into account the effect of charged particles in the ionosphere on the neutral gas dynamics, ionospheric conductivities for different SA levels are included in MUAM. To improve the statistical reliability of the results, two ensembles of model simulations consisting of 16 runs corresponding to the minimum and maximum SA have been obtained. The statistical confidence of average differences in PW amplitudes between high and low SA has been calculated. The results are shown to be reliable in almost the entire altitude range 0–300 km. Results of the simulations have shown for the first time that statistically significant differences in amplitudes of long-period PWs can reach 10–15 % in the middle atmosphere of the Northern Hemisphere, depending on the zonal wave number. At the same time, reflection of PWs at altitudes of lower thermosphere has a significant effect on the PW structure in the middle atmosphere.

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STATISTICALLY SIGNIFICANT ESTIMATES OF INFLUENCE OF SOLAR ACTIVITY ON PLANETARY WAVES IN THE MIDDLE ATMOSPHERE OF THE NORTHERN HEMISPHERE AS DERIVED FROM MUAM MODEL DATA

Solar-Terrestrial Physics ◽

10.12737/stp-54201907 ◽

2019 ◽

Vol 5 (4) ◽

pp. 53-59

Author(s):

Andrey Koval

Keyword(s):

Solar Activity ◽

Northern Hemisphere ◽

Middle Atmosphere ◽

Lower Thermosphere ◽

Planetary Waves ◽

Wave Number ◽

Winter Period ◽

Long Period ◽

Neutral Gas ◽

Solar Radio Flux

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Intercomparison of Middle Atmospheric Meteorological Analyses for the Northern Hemisphere Winter 2009–2010

10.5194/acp-2021-224 ◽

2021 ◽

Author(s):

John P. McCormack ◽

V. Lynn Harvey ◽

Nicholas Pedatella ◽

Dai Koshin ◽

Kaoru Sato ◽

...

Keyword(s):

Northern Hemisphere ◽

Middle Atmosphere ◽

Lower Thermosphere ◽

Planetary Waves ◽

Wave Number ◽

Physical Mechanisms ◽

Wide Range ◽

Zonal Wave Number ◽

Analysis System ◽

Hemisphere Winter

Abstract. Detailed meteorological analyses based on observations extending through the middle atmosphere (~15–100 km altitude) can provide key information to whole atmosphere modelling systems regarding the physical mechanisms linking day-to-day changes in ionospheric electron density to meteorological variability near the Earth’s surface. It is currently unclear how middle atmosphere analyses produced by various research groups consistently represent the wide range of proposed linking mechanisms involving migrating and non-migrating tides, planetary waves, gravity waves, and their impact on the zonal mean state in the mesosphere and lower thermosphere (MLT) region. To begin to address this issue, we present the first intercomparison among four such analyses, JAGUAR-DAS, MERRA-2, NAVGEM-HA, and WACCMX+DART, focusing on the Northern Hemisphere (NH) 2009–2010 winter that includes a major stratospheric sudden warming (SSW) in late January. This intercomparison examines the altitude, latitude, and time dependences of zonal mean zonal winds and temperatures among these four analyses over the 1 December 2009–31 March 2010 period, as well as latitude and altitude dependences of monthly mean amplitudes of the diurnal and semidiurnal migrating solar tides, the eastward propagating diurnal zonal wave number 3 nonmigrating tide, and traveling planetary waves associated with the quasi-5 day and quasi-2-day Rossby modes. Our results show generally good agreement among the four analyses up to the stratopause (~50 km altitude). Large discrepancies begin to emerge in the MLT owing to (1) differences in the types of satellite data assimilated by each system and (2) differences in the details of the global atmospheric models used by each analysis system. The results of this intercomparison provide initial estimates of uncertainty in analyses commonly used to constrain middle atmospheric meteorological variability in whole atmosphere model simulations.

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A comparative study of winds and tidal variability in the mesosphere/lower-thermosphere region over Bulgaria and the UK

Annales Geophysicae ◽

10.1007/s00585-000-1304-3 ◽

2000 ◽

Vol 18 (10) ◽

pp. 1304-1315 ◽

Cited By ~ 15

Author(s):

D. Pancheva ◽

P. Mukhtarov ◽

N. J. Mitchell ◽

A. G. Beard ◽

H. G. Muller

Keyword(s):

Middle Atmosphere ◽

Spatial Scales ◽

Lower Thermosphere ◽

Planetary Waves ◽

Wave Number ◽

Linear Interaction ◽

Zonal Wave Number ◽

Tidal Variability ◽

Cross Wavelet Analysis ◽

The Uk

Abstract. Meteor radars located in Bulgaria and the UK have been used to simultaneously measure winds in the mesosphere/lower-thermosphere region near 42.5°N, 26.6°E and 54.5°N, 3.9°W, respectively, over the period January 1991 to June 1992. The data have been used to investigate planetary waves and diurnal and semidiurnal tidal variability over the two sites. The tidal amplitudes at each site exhibit fluctuations as large as 300% on time scales from a few days to the intra-seasonal, with most of the variability being at intra-seasonal scales. Spectral and cross-wavelet analysis reveals closely related tidal variability over the two sites, indicating that the variability occurs on spatial scales large compared to the spacing between the two radars. In some, but not all, cases, periodic variability of tidal amplitudes is associated with simultaneously present planetary waves of similar period, suggesting the variability is a consequence of non-linear interaction. Calculation of the zonal wave number of a number of large amplitude planetary waves suggests that during summer 1991 the 2-day wave had a zonal wave number of 3, but that during January–February 1991 it had a zonal wave number of 4.Key words: Meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)

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Intercomparison of middle atmospheric meteorological analyses for the Northern Hemisphere winter 2009–2010

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-17577-2021 ◽

2021 ◽

Vol 21 (23) ◽

pp. 17577-17605

Author(s):

John P. McCormack ◽

V. Lynn Harvey ◽

Cora E. Randall ◽

Nicholas Pedatella ◽

Dai Koshin ◽

...

Keyword(s):

Northern Hemisphere ◽

Middle Atmosphere ◽

Lower Thermosphere ◽

Wave Number ◽

Physical Mechanisms ◽

Modeling Systems ◽

Zonal Wave Number ◽

Analysis System ◽

Hemisphere Winter ◽

Wave Induced

Abstract. Detailed meteorological analyses based on observations extending through the middle atmosphere (∼ 15 to 100 km altitude) can provide key information to whole atmosphere modeling systems regarding the physical mechanisms linking day-to-day changes in ionospheric electron density to meteorological variability near the Earth's surface. However, the extent to which independent middle atmosphere analyses differ in their representation of wave-induced coupling to the ionosphere is unclear. To begin to address this issue, we present the first intercomparison among four such analyses, JAGUAR-DAS, MERRA-2, NAVGEM-HA, and WACCMX+DART, focusing on the Northern Hemisphere (NH) 2009–2010 winter, which includes a major sudden stratospheric warming (SSW). This intercomparison examines the altitude, latitude, and time dependences of zonal mean zonal winds and temperatures among these four analyses over the 1 December 2009 to 31 March 2010 period, as well as latitude and altitude dependences of monthly mean amplitudes of the diurnal and semidiurnal migrating solar tides, the eastward-propagating diurnal zonal wave number 3 nonmigrating tide, and traveling planetary waves associated with the quasi-5 d and quasi-2 d Rossby modes. Our results show generally good agreement among the four analyses up to the stratopause (∼ 50 km altitude). Large discrepancies begin to emerge in the mesosphere and lower thermosphere owing to (1) differences in the types of satellite data assimilated by each system and (2) differences in the details of the global atmospheric models used by each analysis system. The results of this intercomparison provide initial estimates of uncertainty in analyses commonly used to constrain middle atmospheric meteorological variability in whole atmosphere model simulations.

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Five-day planetary waves in the middle atmosphere from Odin satellite data and ground-based instruments in Northern Hemisphere summer 2003, 2004, 2005 and 2007

Annales Geophysicae ◽

10.5194/angeo-26-3557-2008 ◽

2008 ◽

Vol 26 (11) ◽

pp. 3557-3570 ◽

Cited By ~ 13

Author(s):

A. Belova ◽

S. Kirkwood ◽

D. Murtagh ◽

N. Mitchell ◽

W. Singer ◽

...

Keyword(s):

Wave Propagation ◽

Northern Hemisphere ◽

Middle Atmosphere ◽

Numerical Models ◽

Baroclinic Instability ◽

Temperature Fluctuations ◽

Planetary Waves ◽

Summer Hemisphere ◽

Winter Hemisphere

Abstract. A number of studies have shown that 5-day planetary waves modulate noctilucent clouds and the closely related Polar Mesosphere Summer Echoes (PMSE) at the summer mesopause. Summer stratospheric winds should inhibit wave propagation through the stratosphere and, although some numerical models (Geisler and Dickinson, 1976) do show a possibility for upward wave propagation, it has also been suggested that the upward propagation may in practice be confined to the winter hemisphere with horizontal propagation of the wave from the winter to the summer hemisphere at mesosphere heights causing the effects observed at the summer mesopause. It has further been proposed (Garcia et al., 2005) that 5-day planetary waves observed in the summer mesosphere could be excited in-situ by baroclinic instability in the upper mesosphere. In this study, we first extract and analyze 5-day planetary wave characteristics on a global scale in the middle atmosphere (up to 54 km in temperature, and up to 68 km in ozone concentration) using measurements by the Odin satellite for selected days during northern hemisphere summer from 2003, 2004, 2005 and 2007. Second, we show that 5-day temperature fluctuations consistent with westward-traveling 5-day waves are present at the summer mesopause, using local ground-based meteor-radar observations. Finally we examine whether any of three possible sources of the detected temperature fluctuations at the summer mesopause can be excluded: upward propagation from the stratosphere in the summer-hemisphere, horizontal propagation from the winter-hemisphere or in-situ excitation as a result of the baroclinic instability. We find that in one case, far from solstice, the baroclinic instability is unlikely to be involved. In one further case, close to solstice, upward propagation in the same hemisphere seems to be ruled out. In all other cases, all or any of the three proposed mechanisms are consistent with the observations.

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Meteor radar observations of mesopause region long-period temperature oscillations

Advances in Radio Science ◽

10.5194/ars-14-169-2016 ◽

2016 ◽

Vol 14 ◽

pp. 169-174

Author(s):

Ch. Jacobi ◽

N. Samtleben ◽

G. Stober

Keyword(s):

Time Scales ◽

Lower Thermosphere ◽

Planetary Waves ◽

Meteor Radar ◽

Mesopause Region ◽

Radar Observations ◽

Long Period ◽

Temperature Oscillations ◽

Wind Measurements

Abstract. Meteor radar observations of mesosphere/lower thermosphere (MLT) daily temperatures have been performed at Collm, Germany since August 2004. The data have been analyzed with respect to long-period oscillations at time scales of 2–30 days. The results reveal that oscillations with periods of up to 6 days are more frequently observed during summer, while those with longer periods have larger amplitudes during winter. The oscillations may be considered as the signature of planetary waves. The results are compared with analyses from radar wind measurements. Moreover, the temperature oscillations show considerable year-to-year variability. In particular, amplitudes of the quasi 5-day oscillation have increased during the last decade, and the quasi 10-day oscillations are larger if the equatorial stratospheric winds are eastward.

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Long-period planetary waves in the mesosphere and lower thermosphere above Davis, Antarctica

Journal of Atmospheric and Solar-Terrestrial Physics ◽

10.1016/j.jastp.2007.06.008 ◽

2007 ◽

Vol 69 (17-18) ◽

pp. 2118-2138 ◽

Cited By ~ 22

Author(s):

D.J. Murphy ◽

W.J.R. French ◽

R.A. Vincent

Keyword(s):

Lower Thermosphere ◽

Planetary Waves ◽

Long Period ◽

Mesosphere And Lower Thermosphere

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

10.5194/egusphere-egu2020-2045 ◽

2020 ◽

Author(s):

Andrey Koval ◽

Nikolai Gavrilov ◽

Alexander Pogoreltsev ◽

Nikita Shevchuk

Keyword(s):

Solar Activity ◽

Atmospheric Circulation ◽

General Circulation ◽

Large Scale ◽

Middle Atmosphere ◽

Thermal Structure ◽

Planetary Waves ◽

Boreal Winter ◽

Zonal Wavenumber ◽

The Mean

<p>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&#160; atmospheric circulation and SPWs at heights 0 &#8211; 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 &#8211; 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. Thus, variable conditions of SPW propagation and reflection at thermospheric altitudes may influence the middle atmosphere circulation, thermal structure and planetary waves at different altitudes.</p>

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