A precipitation parameterization for the Empirical Canadian High Arctic Ionospheric Model (E-CHAIM) and other empirical models

The Empirical Canadian High Arctic Ionospheric Model (E-CHAIM) [1,2,3] was developed as an alternative to the use of traditional global empirical ionospheric models at high latitudes, namely the International Reference Ionosphere (IRI) [4] and NeQuick [5]. While E-CHAIM has been demonstrated significantly improvements over those models at high latitudes [1,2], it lacks the implementation of an auroral precipitation scheme and as such does not account for significantly enhanced E-Region densities in that region [3]. In this study, we will present the new auroral precipitation module that has been developed for implementation with ECHAIM. Assuming a Maxwellian energy distribution, the scheme uses a Fang et. al. (2010) [6] parameterization with an NRLMSIS background neutral atmosphere to represent the vertical structure of precipitation-induced ionization for an input precipitation flux and mean energy. Precipitation flux and mean energy are then modeled based on TIMED GUVI- and DMSP SSUSI-inferred precipitation characteristics.
Beginning with an overview of how the parameterization was implemented, we will further validate the model against Incoherent Scatter Radar (ISR) measurements of auroral electron density and compare the performance of the model with what can be achieved with the parameterization when using the Zhang and Paxton (2008) [7] mean precipitation energy and flux model. We will further examine the possibility of implementing such a scheme in the IRI and examine whether hemispheric differences in mean energy and flux must be accommodated in such a system.