CEDAR Electrodynamics Thermosphere Ionosphere (ETI) Challenge for systematic assessment of ionosphere/thermosphere models: Electron density, neutral density, NmF2, and hmF2 using space based observations

Abstract

In an effort to quantitatively assess the current capabilities of Ionosphere/Thermosphere (IT) models, an IT model validation study using metrics was performed. This study is a main part of the CEDAR Electrodynamics Thermosphere Ionosphere (ETI) Challenge, which was initiated at the CEDAR workshop in 2009 to better comprehend strengths and weaknesses of models in predicting the IT system, and to trace improvements in ionospheric/thermospheric specification and forecast. For the challenge, two strong geomagnetic storms, four moderate storms, and three quiet time intervals were selected. For the selected events, we obtained four scores (i.e., RMS error, prediction efficiency, ratio of the maximum change in amplitudes, and ratio of the maximum amplitudes) to compare the performance of models in reproducing the selected physical parameters such as vertical drifts, electron and neutral densities, NmF2, and hmF2. In this paper, we present the results from comparing modeled values against space‐based measurements including NmF2 and hmF2 from the CHAMP and COSMIC satellites, and electron and neutral densities at the CHAMP satellite locations. It is found that the accuracy of models varies with the metrics used, latitude and geomagnetic activity level.

Thermospheric mass density: A review

“…Kwak et al (2011) investigated the influence of IMF sector polarity changes on CHAMP observations during 2003. Shim et al (2012) compared various empirical and physical models with CHAMP density during six selected storms and three quiet intervals; the empirical models were generally in better agreement with the data.…”

“…Second, the thermosphere is strongly forced by external (especially solar) drivers, with little internal variability, so forecast accuracy depends in large part on forecasts of the drivers. As a result, physical and empirical models currently produce density forecasts with similar accuracy (National Research Council, 2012;Shim et al, 2012). Recent efforts to use physical models for nowcasting and forecasting are reviewed in section 5.1.…”

The International Reference Ionosphere – Status 2013

“…IRI was one of the best performing models in the Electrodynamics Thermosphere Ionosphere (ETI) Challenge of the Coupling, Energetics, and Dynamics of Atmospheric Regions (CEDAR) program of the National Science Foundation (NSF) (Shim et al, 2011;Shim et al, 2012). IRI is acknowledged in 8% of all 2012 Journal of Geophysical Research papers and 15% of all 2012 Radio Science papers.…”

“…The standard IRI model describes average conditions quite well and has shown excellent results in comparisons with other models (Shim et al, 2011;Shim et al, 2012). IRI performance can be even more improved if observations are available for a time of interest in real-time or retrospective.…”

A model of high‐latitude thermospheric density

“…The average error for JB2008 is 19.0% in the Northern Hemisphere and 19.4% in the Southern Hemisphere. Previous studies have reported that the JB2008 model generally performs slightly better than the MSISE-00 model [Bowman et al, 2008b;Shim et al, 2012]. For MSISE-00, the quiet-time densities are computed for ap = 0 nT, and the non-quiet-time densities are obtained for ap = 27 nT.…”