High-latitude ionospheric drivers and their effects on wind patterns in the thermosphere
Abstract
Winds in the thermosphere are highly important for transporting mass, momentum and energy over the globe. It has been moderately difficult to validate how well models reproduce the winds because of a lack of data. In the high latitude region, the ions and neutrals are strongly coupled when the aurora is present, whereas the coupling is weaker when there is no aurora. In this study, we investigate the ability of the Global Ionosphere Thermosphere Model (GITM) to simulate the meso-scale wind structure over Alaska before and during a substorm. Ten distinct numerical simulations of a substorm event that occurred between 02:00 and 17:00 universal time on November 24, 2012 have been preformed. Using GITM, we are able to highlight both subtle and drastic differences in model results affected by various high-latitude ionospheric drivers. Distinct ionospheric inputs considered as drivers include the Weimer potential patterns using IMF solar wind data coupled with the Fuller-Rowell and Evans auroral patterns, SuperDARN fitted potential pattern data, and changes in ionospheric currents measured by the Auroral Electrojet index. We also consider the effects of the boundary between the neutral wind dynamo calculation and the high-latitude imposed electric potential. Neutral wind velocities measured from Scanning Doppler Imager instruments located at three locations in Alaska are then compared to GITM simulated winds for every distinct run. Each component of the wind is compared individually, as they are driven by different forcing terms. Further, electron densities at 240km as a function of location and time are compared with data from the Poker Flat Incoherent Scatter Radar instrument. We have found that differences in the type of input used to model the substorm can lead to significantly disparate results among each individual run. This points to the need to have accurate specifications of the electric potential and auroral precipitation if the wind is to be fully understood.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMSA31A1971L
- Keywords:
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- 2441 IONOSPHERE Ionospheric storms;
- 3369 ATMOSPHERIC PROCESSES Thermospheric dynamics;
- 2407 IONOSPHERE Auroral ionosphere;
- 2447 IONOSPHERE Modeling and forecasting