Measurements of ionospheric parameters above Arecibo, Puerto Rico, have been compared with a computer simulation for a variety of conditions. The simulation includes solutions to the energy, heat flow, continuity, and momentum equations for O+, H+, and electrons. Agreement was found between the measured and calculated electron concentration during geomagnetically quiet conditions. Comparisons for more active conditions indicate a significant upward flow of ionization during the mid-afternoon. Calculated electron temperatures were found to be consistently lower than measured temperatures during the daytime. Calculated values of NmF2 and hmax agreed with measured results expect during the post-midnight peeriod. Calculated values of the ion flux indicate a 24-hour net flow of ionization from the northern to the southern hemisphere amounting to 12% and 6% of the equilibrium flux tube content above 1000 km for the winter solstice and equinox cases, respectively.