Observations of the storm time response of the mid-latitude thermosphere made by a network of Fabry-Perot interferometers
Abstract
We present observations of the thermospheric neutral winds and temperatures obtained from a network of five Fabry-Perot interferometers deployed in the Midwest United States. During a geomagnetic storm on 2 October 2013, the network observed a surge in the westward and equatorward horizontal winds. Coincident with this surge in the horizontal winds, an apparent downward wind of approximately 100 m/s lasting for 6 hours was observed. We interpret the large sustained apparent downward winds as being caused by contamination of the spectral profile of the nominal 630.0-nm emission due dissociative recombination of O2+ by fast O related to the infusion of low-energy O+ ions during the storm. Data from the Helium, Oxygen, Proton, and Electron spectrometer instruments on the twin Van Allen Probes spacecraft support this interpretation, showing a large influx of low-energy ions during the period of apparent downward winds. Temperature measurements indicate an increase in the thermospheric temperatures greater than 400 K during the storm. Coordinated observations of the same thermospheric volume by different FPIs in the network indicate an anisotropy in the temperature measurements, with observations made using lines-of-site close to parallel to the magnetic field lines resulting in hotter temperatures. This effect is also consistent with the infusion of low-energy O+ into the thermosphere. In addition to elucidating important aspects of the mid-latitude thermospheric response to a moderate geomagnetic storm, this study emphasizes the importance of coordinated observations by networks of instruments in studying spatio-temporal dynamics of the thermosphere.
- Publication:
-
40th COSPAR Scientific Assembly
- Pub Date:
- 2014
- Bibcode:
- 2014cosp...40E1951M