Here we assess to what extent the Empirical Canadian High Arctic
Ionospheric Model (E-CHAIM) can reproduce the climatological variations
of vertical Total Electron Content (vTEC) in the Canadian sector. Within
the auroral oval and polar cap, E-CHAIM is found to exhibit Root Mean
Square (RMS) errors in vTEC as low 0.4 TECU during solar minimum summer
but as high as 5.0 TECU during solar maximum equinox conditions. These
errors represent an improvement of up to 8.5 TECU over the errors of the
International Reference Ionosphere (IRI) in the same region. At
sub-auroral latitudes, E-CHAIM RMS errors range between 1.0 TECU and 7.4
TECU, with greatest errors during the equinoxes at high solar activity.
This represents an up to 0.5 TECU improvement over the IRI during summer
but worse performance by up to 2.4 TECU during the winter. Comparisons
of E-CHAIM performance against in situ measurements from the European
Space Agency’s Swarm mission are also conducted, ultimately finding
behaviour consistent with that of vTEC. In contrast to the vTEC results,
however, E-CHAIM and the IRI exhibit comparable performance at Swarm
altitudes, except within the polar cap, where the IRI exhibits
systematic underestimation of electron density by up to 1.0e11 e/m^3.
Conjunctions with mid-latitude ionosondes demonstrate that E-CHAIM’s
errors appear to result from compounding same-signed errors in its NmF2,
hmF2, and topside thickness at these latitudes. Overall, E-CHAIM
exhibits strong performance within the polar cap and auroral oval but
performs comparably to the IRI at sub-auroral latitudes.