Influences on ray tracing modeling of ionospheric trends induced by Earth?s magnetic field and anthropogenic effect

ELIAS, ANA G.; ZOSSI, BRUNO S.; FAGRE, MARIANO; SAAVEDRA ZENON

Congreso; Joint IAPSO-IAMAS-IAGA Assembly 2017; 2017

A comprehensive knowledge of the Earth?s ionosphere, which is a crucial component of the upper atmosphere and of the solar-terrestrial system, is essential in several applications, such as the effective planning and operation of communication and navigation systems. In particular, the ionosphere is an anisotropic and dispersive medium for the propagation of radio waves due to the presence of a magnetic field and free charges. To determine the path and ground range of these radio signals, ray tracing techniques are used which work properly if the refractive index is known in each point of the considered region. Accordingly, a ray tracing algorithm relies on a comprehensive specification of the ionosphere and geomagnetic field along its path. Ionospheric profiles required by most ray tracing algorithms are taken from models that ignore anthropogenic effects over the ionosphere, as well as the consequences of the Earth?s magnetic field secular variation. Using a 3D ray tracing code we analyze ray path and ground range changes due to two long-term processes which affects the ionosphere not considered so far: the cooling and shrinking due to anthropogenic effects and the consequences of Earth?s magnetic field secular variation. Beyond its significance in terms of practical importance compared to other sources of ray tracing errors now, ionosphere long-term trends effects are a challenging and topical scientific issue worth of deep study and comprehension which will surely become more noticeable in the future, either because the increase in greenhouse gases continue, and/or due to the Earth?s magnetic field drastic changes expected during the next reversal.