  The coupling of the atmosphere to the space environment has become recognized
as an important driver of atmospheric chemistry and dynamics. In order to
quantify the effects of particle precipitation on the atmosphere, reliable
global energy inputs on spatial scales commensurate with particle precipitation
variations are required. To that end, we have validated the Special Sensor
Ultraviolet Spectrographic Imagers (SSUSI) products for average electron energy
and electron energy flux by comparing to EISCAT electron density profiles. This
comparison shows that SSUSI FUV observations can be used to provide ionization
rate profiles throughout the auroral region. The SSUSI on board the Defense
Meteorological Satellite Program (DMSP) Block 5D3 satellites provide nearly
hourly, high-resolution UV snapshots of auroral emissions. Here we use the
SSUSI-derived energies and fluxes to drive standard parametrizations in order
to obtain ionization-rate and electron-density profiles in the E-region
(90--150 km), which are then compared to EISCAT ground-based electron density
measurements. We compare the data from two satellites, DMSP F17 and F18, to the
Troms{\o} UHF radar profiles. We find that differentiating between the magnetic
local time (MLT) morning (3--11 h) and evening (15--23 h) provides the best fit
to the ground-based data. The data agree well in the MLT morning sector using a
Maxwellian electron spectrum, while in the evening sector using a Gaussian
spectrum and accounting for bounce-electrons achieved optimum agreement with
EISCAT. Depending on the satellite and MLT, the median of the differences
varies between 0 and 20% above 105 km (F17) and $\pm$15% above 100 km (F18).
Because of the large gradient below those altitudes, the relative differences
get larger without substantially increasing absolute differences, with
virtually no statistically significant differences at the 1-sigma level.
