Superposed epoch analysis of the ionospheric convection evolution during substorms : onset latitude dependence

Grocott, A. and Wild, J.A. and Milan, S.E. and Yeoman, T.K. (2009) Superposed epoch analysis of the ionospheric convection evolution during substorms : onset latitude dependence. Annales Geophysicae, 27 (2). pp. 591-600. ISSN 0992-7689

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Using data from the Super Dual Auroral Radar Network (SuperDARN) we investigate the ionospheric convection response to magnetospheric substorms. Substorms were identified using the Far Ultraviolet (FUV) instrument on board the Imager for Magnetopause-to-Aurora Global Exploration (IMAGE) spacecraft, and were then binned according to the magnetic latitude of their onset. A superposed epoch analysis of the ionospheric convection patterns for each onset-latitude bin was then performed using radar data for the interval 60 min before onset to 90 min after. It is found that lower onset-latitude substorms are associated with generally more enhanced convection than the higher latitude substorms, although they suffer from a significant localised reduction of the flow in the midnight sector during the expansion phase. Higher-latitude substorms are associated with a significant and rapid increase in the nightside convection following substorm onset, with all onset-latitude bins showing an enhancement over onset values by ∼60 min into the expansion phase. A rudimentary inspection of the concurrent auroral evolution suggests that the duration of the flow reduction following substorm onset is dependent on the strength and duration of the expansion phase aurora and its associated conductivity enhancement.

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Journal Article
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Annales Geophysicae
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© Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License.
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?? superdarnsubstormconvection dcs-publications-iddcs-publications-creditsionodcs-publications-personnel-idphysicsearth and planetary sciences (miscellaneous)astronomy and astrophysicsatmospheric sciencegeologyspace and planetary scienceqc physics ??
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Deposited On:
08 Apr 2009 15:39
Last Modified:
31 Dec 2023 00:16