Physics Department Seminar University of Alaska Fairbanks

Special Research Seminar

Local-Scale Neutral Dynamics in the Auroral Zones
Callum Anderson
A candidate finalist for the joint Physics and Space Physics faculty position.




At high-latitudes, the neutral atmosphere above ~100 km is driven predominantly by upward propagating tides and waves, solar ultraviolet heating, and momentum transferred from convecting ions. These forces act over a range of spatial and temporal scales. Our understanding of the slowly-time varying, large scale (~1000 km or more) circulation is relatively complete. In comparison, very little is known about the behavior of the real neutral atmosphere on spatial scales of 500 km or less. Phenomena in this category include vertical winds, gravity waves, horizontal gradients, and the behavior of the wind field in an interface such as the E-region. Small-scale processes such as these are difficult to incorporate into first principles-based numerical models, however they have the potential to significantly impact the global-scale circulation. Vertical winds, for example, can locally perturb the neutral and ion composition, and these perturbations can be transported long distances by fast horizontal winds, or deformed in complex ways by wind gradients. Understanding these processes is therefore very important for accurately modeling the impacts of space-weather events on Earth’s upper atmosphere. This talk will focus on my research into observing neutral thermospheric dynamics on spatial scales of 500 km or less. In particular, I will present neutral wind measurements from a bistatic array of Scanning Doppler Imager’s (SDI’s), an investigation into local-scale ion-neutral coupling, and some new questions raised by recent climatological E-region wind measurements.


Friday, 27 April 2012

IARC Room 501

2:00 PM