1 Improved polar HF propagation using nowcast and forecast space weather parameters

Abstract. The short-term variable impact of the Sun’s photons, solar wind particles, or magnetic field upon the Earth, i.e., space weather, is the major cause of high-latitude ionospheric perturba-tions. It particularly affects HF radio signals reflected from the ionosphere by polar-transiting air-craft. To improve polar HF radio propagation capabilities, we present work in progress on an inno-vative concept using space physics models that are now operationally mature and that are linked to well-known ray-trace computer code. Supplemented with existing, measured electron densities in local areas, the end result will provide substantially improved polar HF aircraft radio communica-tion. We are linking the SOLAR2000 model’s nowcast and 72-hour forecast of solar irradiances and proxies with the GAIM ionosphere model. The 4-D electron density profiles that are output from GAIM are additionally improved by future input of the nowcast/forecast plasma drift velocities from the DICM electric circuit model. The electron densities will be used by the ICEPAC ray-trace model within the Dynacast system to provide a regional polar HF suite of frequencies that are ranked for each waypoint and from every possible service provider. Dynacast electron density measurements may also be incorporated to improve the local HF propagation capability. We are developing a plat-form to link all models and data via automated processes on several servers. The resultant suite o