New Features for the Empirical Canadian High Arctic Ionospheric Model (E-CHAIM) v4.0.0

The Empirical Canadian High Arctic Ionospheric Model (E-CHAIM) is a 3D empirical model of the high latitude electron density designed as an alternative to the use of the International Reference Ionosphere (IRI) at high latitudes. The model was initially developed through Themens et al. [2017, 2018, and 2019] with climatological representations of the F2 peak, topside, and bottomside ionosphere, respectively. The model also includes a storm peak density model to accommodate the high latitude negative ionospheric response to storm-driven changes in thermospheric composition. Since the initial release of the model, auroral electron precipitation was added in v3.1 to account for enhancements in the auroral E-Region [Watson et al., 2021] and a climatological D-Region was added in v3.2 through the integration of the Faraday IRI-2018 [Friedrich and Torkar, 2018]. Here we will discuss the inclusion of solar energetic proton precipitation in the model and compare the resulting electron density enhancements with corresponding increases in riometer absorption and the electron density structures observed through Incoherent Scatter Radar (ISR). We will also conduct a validations of the performance of the auroral electron precipitation module.

References:

Friedrich, M., C. Pock, and K. Torkar (2018). FIRI-2018, an updated empirical model of the lower ionosphere. Journal of Geophysical Research: Space Physics, 123, 6737– 6751. https://doi.org/10.1029/2018JA025437

Themens, D.R., P.T. Jayachandran, A.M. McCaffrey, B. Reid, and R.H. Varney (2019). A bottomside parameterization for the Empirical Canadian High Artic Ionospheric Model (E-CHAIM), Radio Sci., doi: 10.1029/2018RS006748

Themens, D.R., et al. (2018). Topside Electron Density Representations for Middle and High Latitudes: A Topside Parameterization for E-CHAIM based on the NeQuick, J. Geophys. Res. Space Physics, 123, doi: 10.1002/2017JA024817

Themens, D.R., P.T. Jayachandran, I. Galkin, and C. Hall (2017). The Empirical Canadian High Arctic Ionospheric Model (E-CHAIM): NmF2 and hmF2, J. Geophys. Res. Space Physics, doi: 10.1002/2017JA024398

Watson, C., D.R. Themens, and P.T. Jayachandran (2021), Development and validation of precipitation enhanced densities for E-CHAIM, Space Weather, doi:10.1029/2021SW002779