Determination of Night-side Low and Mid-latitude Electron Density Profiles From TIMED/GUVI Data

As part of its normal operation he GUVI instrument aboard the TIMED spacecraft measures 135.6 nm emissions from the Earth's limb. We present a method of inferring electron density profiles from these GUVI data. Our method is restricted to mid and low latitude night-side regions where the dominant source of 135.6 nm emission is atomic oxygen recombination. We account for both the finite field of view and the finite field of regard of GUVI as well as other instrument artifacts. We describe here 1) the mathematical and physical underpinnings of the method, 2) the practical means of implementation, 3) an analysis of the statistical and systematic uncertainties involved in the retrievals, 4) representative electron density profiles retrieved from the GUVI measurements, 5) preliminary comparisons of these results with ionosonde station data and 6) a description of the limitations of the method and prospective areas of improvement.