Super Dual Auroral Radar Network Expansion and its Influence on the
Derived Ionospheric Convection Pattern
Abstract
The Super Dual Auroral Radar Network (SuperDARN) was built to study
ionospheric convection and has in recent years been expanded
geographically. Alongside software developments, this has resulted in
many different versions of the convection maps dataset being available.
Using data from 2012 to 2018, we produce five different versions of the
widely used convection maps, using limited backscatter ranges,
background models and the exclusion/inclusion of data from specific
radar groups such as the mid-latitude radars. This enables us to
simulate how much information was missing from previous decades of
SuperDARN research. We study changes in the Heppner-Maynard boundary,
the cross polar cap potential (CPCP), the number of backscatter echoes
(n) and the χ-squared/n statistic which is a measure of the global
agreement between the measured and fitted velocities. We find that the
CPCP is reduced when the polar cap radars are introduced, but then
increases again when the mid-latitude radars are added. When the
background model is changed from the RG96 model, to the most recent TS18
model, the CPCP tends to decrease for lower values, but tends to
increase for higher values. When comparing to geomagnetic indices, we
find that there is on average a linear relationship between the
Heppner-Maynard boundary and the geomagnetic indices, as well as n,
which breaks at high values (e.g. HMB ~50 degrees) due
to the low observational density. We find that whilst n is important in
constraining the maps (maps with n>400 are unlikely to
change), is insufficient as the sole measure of quality.