Ionospheric modeling for Over the Horizon Radar applications considering solar activity level

ZENÓN SAAVEDRA; ANA G. ELIAS; MIGUEL A. CABRERA

Sunny Beach

Workshop; 7th Workshop: Solar Influences on the Magnetosphere, Ionosphere and Atmosphere; 2015

Space Research and Technology Institute, Bulgarian Academy of Sciences

Over the horizon radar (OTHR) is a high frequency radar system that covers an area located beyond the horizon line using ionospheric reflection. The use of the ionosphere as part of the signal channel implies a substantial uncertainty in the actual ray path due to its non-homogeneous structure and its time variability. In fact, the ionosphere varies in wide range scales, both spatial and temporal. The spatial scale ranges from thousands of kilometers to less than a meter, and time scale from several years to hours and minutes. Several radar parameters have to be matched to the prevailing ionospheric conditions. For example, the Maximum Usable Frequency (MUF) and Least Usable Frequency (LUF), which characterize HF range supported by the ionosphere, strongly depend on theamount of ionization. In this work we will focus on ionospheric variability linked to solar activity variations using the International Reference Ionosphere model (IRI). The variability expected in selected radar parameters will be assessed during maximum and minimum solar activity conditions.