This dataset accompanies the paper titled "Quantifying the Impact of Solar Irradiance Uncertainty on Thermosphere-Ionosphere Variability Using Ensemble Forecasts." The study examines the sensitivity of the thermosphere and ionosphere to variations in solar spectral irradiance. Ensemble simulation experiments were conducted for the 2021/2022 winter period, using both data-driven and parameterized solar irradiance perturbations to assess their impact. The ensemble spread in electron density and neutral temperature is used as a measure of the system's sensitivity to changes in solar irradiance. Simulation results are also compared with satellite observations from Swarm, ICON, and COSMIC-2. files with string "euvac05" are result from EXP1 on table 1 in the paper. files with string "euvac15" are result from EXP2 on table 1 in the paper. files with string "data" are result from EXP3 on table 1 in the paper. files with string "data_doubled" are result from EXP4 on table 1 in the paper. Files beginning with "cosmic_doy" contain the results of comparisons between the ensemble simulation experiments and COSMIC-2 electron density observations. The "doy" portion represents the three-digit day-of-year (DOY) identifier. Files beginning with "icon_might_x" contain the results of comparisons between the ensemble simulation experiments and ICON neutral temperature observations. The "x" indicates the instrument identifier, either MIGHTI-A or MIGHTI-B. Files beginning with "swarm_x" contain the results of comparisons between the ensemble simulation experiments and SWARM neutral density observations. The "x" indicates the instrument identifier, either SWARM-A or SWARM-C.