The Accuracy of Real-time hmF2 Estimation from Ionosondes

• Main Authors: Carlo Scotto, Dario Sabbagh
• Format: Article
• Language: English
• Published: MDPI AG 2020-08-01
• Series: Remote Sensing
• Subjects: ionosonde; ionograms; automatic scaling; electron density profile; Incoherent Scatter Radar; real-time ionospheric models
• Online Access: https://www.mdpi.com/2072-4292/12/17/2671

A total of 4991 ionograms recorded from April 1997 to December 2017 by the Millstone Hill Digisonde (42.6°N, 288.5°E) were considered, with simultaneous <i>N</i>_e(<i>h</i>)_[ISR] profiles recorded by the co-located Incoherent Scatter Radar (ISR). The entire ionogram dataset was scaled with both the Autoscala and ARTIST programs. The reliability of the <i>h</i>_mF2 values obtained by ARTIST and Autoscala was assessed using the corresponding ISR values as a reference. Average errors <i>Δ</i> and the root mean square errors RMSE were computed for the whole dataset. Data analysis shows that both the Autoscala and ARTIST systems tend to underestimate <i>h</i>_mF2 values with |<i>Δ</i>| in all cases less than 10 km. For high magnetic activity ARTIST offers better accuracy than Autoscala, as evidenced by RMSE_[ARTIST]<RMSE_[_Autoscala_], under both daytime and nighttime conditions, and considering all hours of the day. Conversely, under low and medium magnetic activity Autoscala tends to estimate <i>h</i>_mF2 more accurately than the ARTIST system for both daytime and nighttime conditions, when RMSE_[_Autoscala_]<RMSE_[ARTIST]. However, RMSE_[_Autoscala_] slightly exceeds RMSE_[ARTIST] for the day as a whole. RMSE values are generally substantial (RMSE>16 km in all cases), which places a limit on the results obtainable with real-time models that ingest ionosonde data.