Influence of geomagnetic disturbances on mean winds and tides in the mesosphere/lower thermosphere at midlatitudes

<p>Observations of upper mesosphere/lower thermosphere (MLT) wind have been performed at Collm (51.3<span class="inline-formula"><sup>∘</sup></span> N, 13.0<span class="inline-formula"><sup>∘</sup></span> E) and Kazan (56<s...

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Main Authors: C. Jacobi, F. Lilienthal, D. Korotyshkin, E. Merzlyakov, G. Stober
Format: Article
Language:deu
Published: Copernicus Publications 2021-12-01
Series:Advances in Radio Science
Online Access:https://ars.copernicus.org/articles/19/185/2021/ars-19-185-2021.pdf
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author C. Jacobi
F. Lilienthal
D. Korotyshkin
E. Merzlyakov
E. Merzlyakov
G. Stober
author_facet C. Jacobi
F. Lilienthal
D. Korotyshkin
E. Merzlyakov
E. Merzlyakov
G. Stober
author_sort C. Jacobi
collection DOAJ
description <p>Observations of upper mesosphere/lower thermosphere (MLT) wind have been performed at Collm (51.3<span class="inline-formula"><sup>∘</sup></span> N, 13.0<span class="inline-formula"><sup>∘</sup></span> E) and Kazan (56<span class="inline-formula"><sup>∘</sup></span> N, 49<span class="inline-formula"><sup>∘</sup></span> E), using two SKiYMET all-sky meteor radars with similar configuration. Daily vertical profiles of mean winds and tidal amplitudes have been constructed from hourly horizontal winds. We analyse the response of mean winds and tidal amplitudes to geomagnetic disturbances. To this end, we compare winds and amplitudes for very quiet (Ap <span class="inline-formula">≤</span> 5) and unsettled/disturbed (Ap <span class="inline-formula">≥</span> 20) geomagnetic conditions. Zonal winds in both the mesosphere and lower thermosphere are weaker during disturbed conditions for both summer and winter. The summer equatorward meridional wind jet is weaker for disturbed geomagnetic conditions. Tendencies for geomagnetic effects on mean winds over Collm and Kazan qualitatively agree during most of the year. For the diurnal tide, amplitudes in summer are smaller in the mesosphere and greater in the lower thermosphere, but no clear tendency is seen for winter. Semidiurnal tidal amplitudes increase during geomagnetic active days in summer and winter. Terdiurnal amplitudes are slightly reduced in the mesosphere during disturbed days, but no clear effect is visible for the lower thermosphere. Overall, while there is a noticeable effect of geomagnetic variability on the mean wind, the effect on tidal amplitudes, except for the semidiurnal tide, is relatively small and partly different over Collm and Kazan.</p>
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spelling doaj.art-c0ce7b7bacb64e88bb53b23fbf27f20b2022-12-21T17:49:54ZdeuCopernicus PublicationsAdvances in Radio Science1684-99651684-99732021-12-011918519310.5194/ars-19-185-2021Influence of geomagnetic disturbances on mean winds and tides in the mesosphere/lower thermosphere at midlatitudesC. Jacobi0F. Lilienthal1D. Korotyshkin2E. Merzlyakov3E. Merzlyakov4G. Stober5Institute for Meteorology, Universität Leipzig, Stephanstr. 3, 04103 Leipzig, GermanyInstitute for Meteorology, Universität Leipzig, Stephanstr. 3, 04103 Leipzig, GermanyRadiophysics Department, Kazan (Volga Region) Federal University, Kazan, Russia​​​​​​​Radiophysics Department, Kazan (Volga Region) Federal University, Kazan, Russia​​​​​​​Institute for Experimental Meteorology, Research and Production Association “Typhoon”, Obninsk, RussiaInstitute of Applied Physics, Microwave Physics, University of Bern, Bern, Switzerland<p>Observations of upper mesosphere/lower thermosphere (MLT) wind have been performed at Collm (51.3<span class="inline-formula"><sup>∘</sup></span> N, 13.0<span class="inline-formula"><sup>∘</sup></span> E) and Kazan (56<span class="inline-formula"><sup>∘</sup></span> N, 49<span class="inline-formula"><sup>∘</sup></span> E), using two SKiYMET all-sky meteor radars with similar configuration. Daily vertical profiles of mean winds and tidal amplitudes have been constructed from hourly horizontal winds. We analyse the response of mean winds and tidal amplitudes to geomagnetic disturbances. To this end, we compare winds and amplitudes for very quiet (Ap <span class="inline-formula">≤</span> 5) and unsettled/disturbed (Ap <span class="inline-formula">≥</span> 20) geomagnetic conditions. Zonal winds in both the mesosphere and lower thermosphere are weaker during disturbed conditions for both summer and winter. The summer equatorward meridional wind jet is weaker for disturbed geomagnetic conditions. Tendencies for geomagnetic effects on mean winds over Collm and Kazan qualitatively agree during most of the year. For the diurnal tide, amplitudes in summer are smaller in the mesosphere and greater in the lower thermosphere, but no clear tendency is seen for winter. Semidiurnal tidal amplitudes increase during geomagnetic active days in summer and winter. Terdiurnal amplitudes are slightly reduced in the mesosphere during disturbed days, but no clear effect is visible for the lower thermosphere. Overall, while there is a noticeable effect of geomagnetic variability on the mean wind, the effect on tidal amplitudes, except for the semidiurnal tide, is relatively small and partly different over Collm and Kazan.</p>https://ars.copernicus.org/articles/19/185/2021/ars-19-185-2021.pdf
spellingShingle C. Jacobi
F. Lilienthal
D. Korotyshkin
E. Merzlyakov
E. Merzlyakov
G. Stober
Influence of geomagnetic disturbances on mean winds and tides in the mesosphere/lower thermosphere at midlatitudes
Advances in Radio Science
title Influence of geomagnetic disturbances on mean winds and tides in the mesosphere/lower thermosphere at midlatitudes
title_full Influence of geomagnetic disturbances on mean winds and tides in the mesosphere/lower thermosphere at midlatitudes
title_fullStr Influence of geomagnetic disturbances on mean winds and tides in the mesosphere/lower thermosphere at midlatitudes
title_full_unstemmed Influence of geomagnetic disturbances on mean winds and tides in the mesosphere/lower thermosphere at midlatitudes
title_short Influence of geomagnetic disturbances on mean winds and tides in the mesosphere/lower thermosphere at midlatitudes
title_sort influence of geomagnetic disturbances on mean winds and tides in the mesosphere lower thermosphere at midlatitudes
url https://ars.copernicus.org/articles/19/185/2021/ars-19-185-2021.pdf
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