Is There a Compositional Signature That Could Explain Middle Latitude Ionospheric Signatures during Sudden Stratospheric Warmings?

GUVI data are used in this presentation to determine if there are compositional changes at middle and high latitudes during Sudden Stratospheric Warmings (SSWs) that could explain observations of middle latitude ionospheric signatures during these events. A mechanism currently exists that can explain why the equatorial anomalies respond significantly to SSWs. In this mechanism the E - region dynamo is perturbed by upwardly propagating tides and gravity waves. The changing electric field can then alter the response of the equatorial anomalies to these events. It is more difficult to understand why the middle-latitude, F2-region ionosphere could respond to these events as it is, at most, weakly dependent on the E-region dynamo. Here we look at whether there are changes in composition during these events that are not seen at other times and postulate a mechanism by which these composition changes could occur.