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Impact of the lower atmosphere on the ionosphere response to a geomagnetic superstorm
Author(s) -
Pedatella N. M.
Publication year - 2016
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2016gl070592
Subject(s) - tec , ionosphere , thermosphere , atmosphere (unit) , forcing (mathematics) , atmospheric sciences , earth's magnetic field , total electron content , geomagnetic storm , storm , climatology , geology , environmental science , geophysics , meteorology , physics , quantum mechanics , magnetic field , oceanography
Numerical simulations in the National Center for Atmospheric Research (NCAR) thermosphere‐ionosphere‐electrodynamics general circulation model (TIE‐GCM) are performed to elucidate the impacts of lower atmosphere forcing on the ionosphere response to a geomagnetic superstorm. In particular, how the ionosphere variability due to the October 2003 Halloween storm would be different if it occurred in January coincident with a major sudden stratosphere warming (SSW) event is investigated. The TIE‐GCM simulations reveal that the E × B vertical drift velocity and total electron content (TEC) respond differently to the geomagnetic forcing when the lower atmosphere forcing is representative of SSW conditions compared to climatological lower atmosphere forcing conditions. Notably, the storm time variations in the E × B vertical drift velocity differ when the SSW‐induced zonal mean and tidal variability in the lower thermosphere are considered, and this is in part due to effects of the SSW on the equatorial ionosphere being potentially misinterpreted as being of geomagnetic origin. Differences in the TEC response to the geomagnetic storm can be up to 100% (∼30 TEC unit (TECU: 1 TECU = 10 16 el m −2 )) of the storm‐induced TEC change, and the temporal variability of the TEC during the storm recovery phase is considerably different if SSW effects are considered. The results demonstrate that even during periods of extreme geomagnetic forcing, it is important to consider the effects of lower atmosphere forcing on the ionosphere variability.