[P-EM12] Coupling Processes in the Atmosphere-Ionosphere System

[PEM12-26] Disturbance dynamo winds driven by geomagnetic storms during 1000 days of the NASA ICON mission.

*Thomas J Immel¹、Lily Olgesby¹、Brian J Harding¹、Yen-Jung Wu¹、Triplett C Colin¹、Roderick A Heelis²、Romina Nikoukar³ (1.University of California, Berkeley、2.University of Texas at Dallas、3.APL/Johns Hopkins University)

キーワード：Thermospheric Storms, Geomagnetic activity, Ionospheric dynamo

The MIGHTI instrument on the Ionospheric Connection Explorer (ICON) mission provides the first complete and nearly continuous measurements of thermosphere winds in the daytime E-region. During solar minimum, the observation of significant variability in the winds is related to changes in drivers originating in the lower and middle atmosphere. However, the influences of geomagnetic activity are also evident. With precision better than 5 m/s, MIGHTI observed dozens of events where the effects of auroral heating are statistically significant. Though the Joule heating associated with auroral enhancements is a well known driver of winds and large-scale waves in the upper thermosphere, the nature of these events varies a great deal. Observed as transient departures from climatology in meridional winds at middle and low latitudes, a majority of the events show the largest effects above 200 km (ionospheric F-region). There is a smaller set where the disturbance grows larger below 200 km and is greatest in the daytime ionospheric E-region. Further, when the zonal wind effects are observed, only a small set of these disturbances is found to be associated with changes in mean zonal winds. Storm-time disturbances in zonal winds are the most effective in driving changes in the low latitude wind dynamo and affecting the balance of plasma production/loss. For that reason we investigate the nature of these disturbances and consider the relation of auroral heating to disturbance winds.