Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Solar and lunar ionospheric electrodynamic effects during stratospheric sudden warmings
AU - Yamazaki (YY), Yosuke
PY - 2014/11
Y1 - 2014/11
N2 - Both solar and lunar atmospheric tides are believed to drive ionospheric electrodynamic effects during stratospheric sudden warmings (SSWs), but their relative importance is not well understood. In this study, long-term records (1958–2007) of the geomagnetic field are analyzed to determine the average solar (S) and lunar (L) ionospheric current systems for SSW and non-SSW periods. It is found that the L current intensity is enhanced during SSWs approximately by 75%, while the relative change in the S current intensity is much smaller (~10%). Nonetheless, absolute changes are comparable in the S and L current intensities. At the magnetic equator, semidiurnal perturbations produced by S and L currents reinforce or cancel each other depending on the phase of the moon, creating lunar-dependent recurrent onset in the total effect. These results indicate that both S and L contributions need to be considered to understand ionospheric variability during SSWs.
AB - Both solar and lunar atmospheric tides are believed to drive ionospheric electrodynamic effects during stratospheric sudden warmings (SSWs), but their relative importance is not well understood. In this study, long-term records (1958–2007) of the geomagnetic field are analyzed to determine the average solar (S) and lunar (L) ionospheric current systems for SSW and non-SSW periods. It is found that the L current intensity is enhanced during SSWs approximately by 75%, while the relative change in the S current intensity is much smaller (~10%). Nonetheless, absolute changes are comparable in the S and L current intensities. At the magnetic equator, semidiurnal perturbations produced by S and L currents reinforce or cancel each other depending on the phase of the moon, creating lunar-dependent recurrent onset in the total effect. These results indicate that both S and L contributions need to be considered to understand ionospheric variability during SSWs.
KW - Ionospheric current systems
KW - Stratospheric sudden warming
KW - Atmospheric tides
KW - Geomagnetic daily variations
KW - Sq
KW - L
U2 - 10.1016/j.jastp.2014.08.001
DO - 10.1016/j.jastp.2014.08.001
M3 - Journal article
VL - 119
SP - 138
EP - 146
JO - Journal of Atmospheric and Solar-Terrestrial Physics
JF - Journal of Atmospheric and Solar-Terrestrial Physics
SN - 1364-6826
ER -