The Fast Borealis Ionosphere: High Time-resolution Mapping of Polar
Ionospheric Flows with SuperDARN
Abstract
Recent improvements to hardware for the Super Dual Auroral Radar Network
systems operated by the University of Saskatchewan (named Borealis) have
allowed for greater control of radar transmit and receive
functionalities than previously possible. One of these functionalities
is the application of a new operational mode, known as wide-beam
imaging, which vastly improves the temporal resolution of the radars
without compromising their spatial coverage. Wide-beam imaging allows
for the retrieval of line-of-sight ionospheric drift velocities at a
temporal resolution of 3.7\,s, a sixteen-fold improvement
from the one-minute resolution offered by traditional operational modes.
In this paper, we use wide-beam data from the Borealis SuperDARN
systems, located in Canada, to derive local horizontal ionospheric
plasma velocity fields above Northern Canada, Greenland, and the polar
cap, at a 3.7\,s temporal resolution. For this local
fitting of ionospheric velocity data, we use the Local Mapping of
Ionospheric Electrodynamics (Lompe) spherical elementary current systems
technique. This new data product, which we call the Fast Borealis
Ionosphere (FBI), is compared to both the global SuperDARN spherical
harmonic convection pattern data product (the Map Potential technique),
as well as Lompe convection patterns derived using the traditional
SuperDARN narrow-beam scanning mode. We show that Lompe systematically
produces a better representation of the underlying radar velocity data
than Map Potential, that the 3.7\,s wide-beam data contains
a significant amount more ionospheric variability than narrow-beam, and
that the high time-resolution convection patterns can resolve dynamic
ionospheric events lasting on the order of tens of seconds.