Trajectories of air parcel transport driven by thermospheric winds reconstructed using ground-based Fabry-Perot observations from Alaska and Antarctica
Abstract
Many aspects of the response of Earth's thermosphere to space weather drivers involve transport of air parcels by neutral winds. However transport trajectories are dependent on all three wind components, as well as their variations over all four spatio-temporal dimensions. Measuring the actual thermospheric wind field with adequate dimensionality, sampling resolution, and coverage to allow trajectories to be reconstructed is thus an extremely challenging observational problem, and one for which a fully satisfactory solution does not yet exist. Nevertheless, meaningful progress on this problem is now possible, as a result of the recent deployement of arrays of ground-based all-sky imaging Doppler spectrometers that can map the thermospheric wind field over regions 1000 km across with 100 km spatial resolution and a few minutes temporal resolution. Here we will present recent results of air parcel trajectories reconstructed using Scanning Doppler Imager (SDI) wind data from both Alaska and Antarctica. In Alaska we have four SDI instruments viewing a common volume with overlapping fields of view. This geometry allows true four-dimensional reconstructions of the three-component vector wind field, albeit with crude vertical resolution, over only a limited geographic area ( 1 million square meters), and only during times when aurorally excited optical emissions exhibit active height variations. Results show that air parcels can follow far more complex trajectories than previously expected. In Antarctica, our ability to reconstruct air parcel trajectories is much cruder, owing to there being only two SDI instruments, whose fields of view do not overlap. However their greater separation does mean that we can, at times, follow the transport over far longer distances.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMSM41A..07C
- Keywords:
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- 3369 Thermospheric dynamics;
- ATMOSPHERIC PROCESSESDE: 2431 Ionosphere/magnetosphere interactions;
- IONOSPHEREDE: 2704 Auroral phenomena;
- MAGNETOSPHERIC PHYSICSDE: 2776 Polar cap phenomena;
- MAGNETOSPHERIC PHYSICS