摘要：Ground‐based radar sounders are used to characterize the dynamics and chemistry of Earth's upper atmosphere by using measurements of ionospheric peak electron density ( N m F 2 ) and its associated altitude ( h m F 2 ). Continuous sounder observations of the E and F regions of the ionosphere have been carried out regularly at dozens of stations worldwide since the midtwentieth century. A deep understanding of short‐ and long‐term upper atmospheric variability depends on a fundamental understanding of these observational data. The manual analysis of historical analog (predigital age) ionograms to derive the plasma frequency profiles and the ionospheric parameters h m F 2 and N m F 2 is a tedious procedure and susceptible to human error. In order to better understand this human error, a study is conducted in which ionograms from vertical sounders are manually scaled by a team of ionospheric researchers. The results of the study are then used to estimate the variability of the hand‐scaled ionospheric parameters f o F 2 and f o E . Those results are then used to estimate the downstream impact on ionospheric models that use f o F 2 and f o E as input. The results demonstrate that there can be large variability in the manual scaling of f o F 2 and f max E from vertical incidence ionograms. However, the participants did typically better than 5% uncertainty for benign ionograms. A long‐term analysis of h m F 2 modeling exhibits low sensitivity to statistical errors imposed on f o F 2 and f o E , but a short‐term analysis showed that modeled h m F 2 , neutral winds, and electron densities can be very different when small adjustments are made to f o F 2 and f max E .
