Overview
ISO 16457:2022 specifies the International Reference Ionosphere (IRI) model and options for plasmasphere extensions. The standard guides users on how to represent the global distribution of electron density, electron and ion temperatures, ion composition, and total electron content (TEC) in the Earth’s ionosphere and lower plasmasphere. Coverage is for altitudes from 50 km to 1 500 km, geographic latitudes 80°S to 80°N, and longitudes 0°E to 360°E, for any time of day, day of year, and levels of solar and magnetic activity. Annex A introduces ionospheric and plasmaspheric physics; Annex B summarizes relevant physical models.
Key topics and technical requirements
- Model scope and outputs
- Monthly climatological averages of electron density, electron/ion temperatures, ion composition, and integrated TEC.
- Geographic and temporal coverage
- Global coverage (80°S–80°N, 0°–360°E); any universal time and day of year.
- Plasmasphere extensions
- Several options described: extrapolation of IRI profiles, Global Core Plasma Model (GCPM), IMAGE/RPI, and IZMIRAN extensions.
- Real‑time IRI
- The 2022 edition adds guidance on a real‑time IRI implementation for nowcasting ionospheric conditions.
- Model inputs and indices
- Uses solar and geomagnetic activity indices (e.g., F10.7, Kp/ap, sunspot number variants) and GNSS-derived TEC indices where applicable.
- Accuracy and validation
- Clause on model accuracy, choice of sub-models, and comparison with measurements (ionosondes, incoherent scatter radars, satellite in situ and topside sounders).
- Informative annexes
- Annex A (physics primer) and Annex B (overview of physical models) to aid correct interpretation and implementation.
Applications and practical value
ISO 16457:2022 is intended for anyone who needs standardized ionospheric/plasmaspheric parameters for:
- GNSS and satellite navigation (TEC corrections, positioning accuracy)
- Satellite communications and link budgeting (ionospheric delays and scintillation assessment)
- HF/VHF radio propagation planning and frequency management
- Space weather monitoring and operations (nowcasts/forecasts of ionospheric disturbances)
- Remote sensing and radio astronomy where ionospheric refraction and delay affect measurements
- Orbit determination and mission design requiring ionospheric drag or signal delay models
Who should use this standard
- Space agencies, satellite operators, GNSS service providers
- Aerospace engineers and mission planners
- Radio and telecommunications system designers
- Space weather researchers and operational centers
- Ionospheric model developers and data assimilation teams
Related guidance
- IRI is an internationally maintained empirical model (COSPAR/URSI). ISO 16457:2022 provides the standardized framework and references to commonly used IRI submodels and plasmasphere extensions for consistent implementation and interoperability.