TY - JOUR

T1 - Sensitivity of the 4–10‐day planetary wave structures in the middle atmosphere to the solar activity effects in the thermosphere.

AU - Koval , Andrey V.

AU - Gavrilov, Nikolai M.

AU - Didenko , Ksenia A.

AU - Ermakova , Tatiana S.

AU - Savenkova , Elena N.

N1 - Publisher Copyright: © 2022 by the authors.

PY - 2022/8

Y1 - 2022/8

N2 - Numerical simulation of the general atmospheric circulation was performed to estimate changes in amplitudes of the westward-travelling planetary waves (PWs) at altitudes from the Earth’s surface up to 300 km under different solar activity (SA) levels. The three-dimensional nonlinear mechanistic model of circulation of the middle and upper atmosphere “MUAM” was used. The atmospheric general circulation and PW amplitudes were calculated based on ensembles containing 16 model runs for conditions corresponding to low and high SA. PWs having periods of 4–10 days were considered. Comparison with the data of digital ionosondes showed that the MUAM model is capable of reproducing the considered PW modes at thermospheric heights. It is shown that under high SA conditions, PW amplitudes are significantly larger in the thermosphere and smaller in the middle atmosphere. The observed PW structures are influenced not only by changes in atmospheric refractive index and Eliassen–Palm flux but also by varying PW reflection in the lower thermosphere, which can change proportions of the wave energy transferred from the lower atmosphere to the upper layers and reflected downwards.

AB - Numerical simulation of the general atmospheric circulation was performed to estimate changes in amplitudes of the westward-travelling planetary waves (PWs) at altitudes from the Earth’s surface up to 300 km under different solar activity (SA) levels. The three-dimensional nonlinear mechanistic model of circulation of the middle and upper atmosphere “MUAM” was used. The atmospheric general circulation and PW amplitudes were calculated based on ensembles containing 16 model runs for conditions corresponding to low and high SA. PWs having periods of 4–10 days were considered. Comparison with the data of digital ionosondes showed that the MUAM model is capable of reproducing the considered PW modes at thermospheric heights. It is shown that under high SA conditions, PW amplitudes are significantly larger in the thermosphere and smaller in the middle atmosphere. The observed PW structures are influenced not only by changes in atmospheric refractive index and Eliassen–Palm flux but also by varying PW reflection in the lower thermosphere, which can change proportions of the wave energy transferred from the lower atmosphere to the upper layers and reflected downwards.

KW - numerical modeling; planetary waves; solar activity; atmospheric dynamics; MUAM

KW - numerical modeling

KW - planetary waves

KW - solar activity

KW - atmospheric dynamics

KW - MUAM

UR - http://www.scopus.com/inward/record.url?scp=85137269684&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/016b4d26-a8df-3500-9864-6b4748c11160/

U2 - https://doi.org/10.3390/atmos13081325

DO - https://doi.org/10.3390/atmos13081325

M3 - Article

VL - 13

JO - ATMOSPHERE

JF - ATMOSPHERE

SN - 1598-3560

IS - 8

M1 - 1325

ER -