TY - JOUR
T1 - Effect of intrinsic magnetic field decrease on the low- to middle-latitude upper atmosphere dynamics simulated by GAIA
AU - Tao, Chihiro
AU - Jin, Hidekatsu
AU - Shinagawa, Hiroyuki
AU - Fujiwara, Hitoshi
AU - Miyoshi, Yasunobu
N1 - Funding Information:
The meteorological reanalysis data set used for this study is provided from the Japanese 25 year Reanalysis (JRA-25), the cooperative research project carried out by the Japan Meteorological Agency (JMA), and the Central Research Institute of Electric Power Industry (CRIEPI). The model computation was carried out using the computer facility at the National Institute of Information and Communications Technologies. Model results will be provided to the scientific community upon request (contact: chihiro.tao@nict.go.jp). This work was supported by MEXT/JSPS KAKENHI grants JP15H05813, JP15H05815, and JP15H05816. We thank the referees and the Editor for their productive and valuable comments.
PY - 2017/9
Y1 - 2017/9
N2 - The effects of decreasing the intrinsic magnetic field on the upper atmospheric dynamics at low to middle latitudes are investigated using the Ground-to-topside model of Atmosphere and Ionosphere for Aeronomy (GAIA). GAIA incorporates a meteorological reanalysis data set at low altitudes (<30 km), which enables us to investigate the atmospheric response to various waves under dynamic and chemical interactions with the ionosphere. In this simulation experiment, we reduced the magnetic field strength to as low as 10% of the current value. The averaged neutral velocity, density, and temperature at low to middle latitudes at 300 km altitude show little change with the magnetic field variation, while the dynamo field, current density, and the ionospheric conductivities are modified significantly. The wind velocity and tidal wave amplitude in the thermosphere remain large owing to the small constraint on plasma motion for a small field. On the other hand, the superrotation feature at the dip equator is weakened by 20% for a 10% magnetic field because the increase in ion drag for the small magnetic field prevents the superrotation.
AB - The effects of decreasing the intrinsic magnetic field on the upper atmospheric dynamics at low to middle latitudes are investigated using the Ground-to-topside model of Atmosphere and Ionosphere for Aeronomy (GAIA). GAIA incorporates a meteorological reanalysis data set at low altitudes (<30 km), which enables us to investigate the atmospheric response to various waves under dynamic and chemical interactions with the ionosphere. In this simulation experiment, we reduced the magnetic field strength to as low as 10% of the current value. The averaged neutral velocity, density, and temperature at low to middle latitudes at 300 km altitude show little change with the magnetic field variation, while the dynamo field, current density, and the ionospheric conductivities are modified significantly. The wind velocity and tidal wave amplitude in the thermosphere remain large owing to the small constraint on plasma motion for a small field. On the other hand, the superrotation feature at the dip equator is weakened by 20% for a 10% magnetic field because the increase in ion drag for the small magnetic field prevents the superrotation.
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U2 - 10.1002/2017JA024278
DO - 10.1002/2017JA024278
M3 - Article
AN - SCOPUS:85048905321
SN - 2169-9380
VL - 122
SP - 9751
EP - 9762
JO - Journal of Geophysical Research: Space Physics
JF - Journal of Geophysical Research: Space Physics
IS - 9
ER -