Application of a Multi‐Layer Artificial Neural Network in a 3‐D Global Electron Density Model Using the Long‐Term Observations of COSMIC, Fengyun‐3C, and Digisonde. Issue 3 (25th March 2021)

• Record Type: Journal Article
• Authors: Li, Wang; Zhao, Dongsheng; He, Changyong; Shen, Yi; Hu, Andong; Zhang, Kefei
• Is Part Of: Space weather. Volume 19:Issue 3(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-03-25
• Subjects: COSMIC mission -- equatorial ionization anomaly -- FY‐3C -- ionospheric model -- neural network; Space environment -- Periodicals; 551.509992
• DOI: 10.1029/2020SW002605
• Languages: English
• ISSNs: 1542-7390

Abstract

Abstract: The ionosphere plays an important role in satellite navigation, radio communication, and space weather prediction. However, it is still a challenging mission to develop a model with high predictability that captures the horizontal‐vertical features of ionospheric electrodynamics. In this study, multiple observations during 2005–2019 from space‐borne global navigation satellite system (GNSS) radio occultation (RO) systems (COSMIC and FY‐3C) and the Digisonde Global Ionosphere Radio Observatory are utilized to develop a completely global ionospheric three‐dimensional electron density model based on an artificial neural network, namely ANN‐TDD. The correlation coefficients of the predicted profiles all exceed 0.96 for the training, validation and test datasets, and the minimum root‐mean‐square error of the predicted residuals is 7.8 × 10 4 el/cm 3 . Under quiet space weather, the predicted accuracy of the ANN‐TDD is 30%–60% higher than the IRI‐2016 at the Millstone Hill and Jicamarca incoherent scatter radars. However, the ANN‐TDD is less capable of predicting ionospheric dynamic evolution under severe geomagnetic storms compared to the IRI‐2016 with the STORM option activated. Additionally, the ANN‐TDD successfully reproduces the large‐scale horizontal‐vertical ionospheric electrodynamic features, including seasonal variation and hemispheric asymmetries. These features agree well with the structure revealed by the RO profiles derived from the FORMOSAT/COSMIC‐2 mission. Furthermore, the ANN‐TDD successfully captures the prominent regional ionospheric patterns, including the equatorial ionization anomaly, Weddell Sea anomaly and mid‐latitude summer nighttime anomaly. The new model is expected to play an important role in the application of GNSS navigation and in the explanation of the physical mechanisms involved. Key Points: An artificial neural network‐based electron density model is developed using the observations obtained from COSMIC, FY‐3C, and Digisondes ANN‐TDD has a strong predicting capability in high‐low solar activities and quiet‐disturbed space conditions compared with ISR and IRI‐2016 ANN‐TDD model successes to reproduce ionospheric seasonal variations and spatial prominent patterns well including the EIA, WSA, and MSNA