Ionosphere variability during the 2009 SSW: Influence of the lunar semidiurnal tide and mechanisms producing electron density variability. Issue 5 (7th May 2014)

• Record Type: Journal Article
• Authors: Pedatella, N. M.; Liu, H.‐L.; Sassi, F.; Lei, J.; Chau, J. L.; Zhang, X.
• Is Part Of: Journal of geophysical research. Volume 119:Issue 5(2014:May)
• Page Start: 3828
• Page End: 3843
• Publication Date: 2014-05-07
• Subjects: Magnetospheric physics -- Periodicals; Space environment -- Periodicals; Cosmic physics -- Periodicals; Planets -- Atmospheres -- Periodicals; Heliosphere (Astrophysics) -- Periodicals; Geophysics -- Periodicals; 523.01
• DOI: 10.1002/2014JA019849
• Languages: English
• ISSNs: 2169-9380

Abstract

<abstract abstract-type="main" id="jgra50995-abs-0001"> <title>Abstract</title> <p id="jgra50995-para-0001">To investigate ionosphere variability during the 2009 sudden stratosphere warming (SSW), we present simulation results that combine the Whole Atmosphere Community Climate Model Extended version and the thermosphere‐ionosphere‐mesosphere electrodynamics general circulation model (TIME‐GCM). The simulations reveal notable enhancements in both the migrating semidiurnal solar (<italic>S</italic><italic>W</italic>2) and lunar (M<sub>2</sub>) tides during the SSW. The <italic>S</italic><italic>W</italic>2 and M<sub>2</sub> amplitudes reach ∼50 m s<sup>−1</sup> and ∼40 m s<sup>−1</sup>, respectively, in zonal wind at <italic>E</italic> region altitudes. The dramatic increase in the M<sub>2</sub> at these altitudes influences the dynamo generation of electric fields, and the importance of the M<sub>2</sub> on the ionosphere variability during the 2009 SSW is demonstrated by comparing simulations with and without the M<sub>2</sub>. TIME‐GCM simulations that incorporate the M<sub>2</sub> are found to be in good agreement with Jicamarca Incoherent Scatter Radar vertical plasma drifts and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) observations of the maximum <italic>F</italic> region electron density. The agreement with observations is worse if the M<sub>2</sub> is not included in the simulation, demonstrating that the lunar tide is an important contributor to the ionosphere variability during the 2009 SSW. We additionally investigate sources of the <italic>F</italic> region electron density variability during the SSW. The primary driver of the electron density variability is changes in electric fields. Changes in meridional neutral winds and thermosphere composition are found to also contribute to the electron density variability during the 2009 SSW. The electron density variability for the 2009 SSW is therefore not solely due to variability in electric fields as previously thought.</p> </abstract>