Publication Date:
2015-06-20
Description:
We report a significant poleward surge in thermospheric winds at subauroral and mid latitudes following the 17–18 March 2015 great geomagnetic storm. This pre-midnight surge is preceded by strong westward winds. These disturbances were observed over three sites with geodetic latitudes 35-42°N in the American sector by Fabry-Perot interferometers at 630-nm wavelength. Prior to the wind disturbances, subauroral polarization streams (SAPS), were measured by the Millstone Hill incoherent scatter radar between 20–02 UT. We identify the observed neutral wind variations as driven by SAPS, through a scenario where strong ion flows cause a westward neutral wind, subsequently establishing a poleward wind surge due to the poleward Coriolis force on that westward wind. These regional disturbances appear to have prevented the well-known storm time equatorward wind surge from propagating into low latitudes, with the consequence that the classic disturbance dynamo mechanism failed to occur.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
Permalink