Human-Error Contributions to Observations of Thermospheric Dynamics and Chemistry

Bottomside sounders may be used to characterize the dynamics and chemistry of Earth’s upper atmosphere by using measurements of ionospheric peak electron density (N_mF₂) and its associated altitude (h_mF₂). Continuous sounder observations in the E and F regions of the ionosphere have been regularly carried out at dozens of stations worldwide since the mid-twentieth century. A deeper understanding of short-term and long-term (seasonal, inter-annual, multi-decadal) upper atmospheric variability depends on a fundamental understanding of the sounder data sets. The analyses of historical analog (pre-digital age) ionograms to derive the plasma frequency profiles and the ionospheric parameters h_mF₂ and N_mF₂ is a tedious procedure and susceptible to human error. In order to better understand this human error, a study was recently conducted in which multiple modern vertical incidence soundings (ionograms) were manually-scaled individually by each member of a team of ionospheric experts. The resulting analyses are used to characterize and quantify human-related error in ionosonde data that have been scaled by experienced operators.