On some consequences of upper atmosphere cooling over HF signal propagation

MARIANO FAGRE; ANA G. ELIAS; BRUNO S. ZOSSI; ZENÓN SAAVEDRA

Hefei

Workshop; 10th Workshop on Long-Term Changes and Trends in the Atmosphere; 2018

University of Science and Technology of China

The Earth?s upper atmosphere, in particular the ionosphere, plays a key role in several applications such as the effective planning and operation of communication and navigation systems that need specifications related to high frequency (HF) radio wave propagation through the ionospheric plasma. This is because the ionosphere is an anisotropic and dispersive medium for HF propagation due to the presence of free charges and a magnetic field. To determine the path and ground range of these radio signals, ray tracing techniques are used which relies on specifications of the ionosphere along its path. Using a 3D ray tracing code we analyze ray path and ground range changes due to the ionosphere cooling and shrinking expected from anthropogenic effects. Changes in traveling ionospheric disturbances, their effect on ray paths, and MUF values are analyzed as well. Although the assessed variations are small compared to other sources of ray tracing errors, ionosphere long-term trends effects are a challenging and topical scientific issue worth of deep study and comprehension which can become more noticeable in the future if the increase in greenhouse gases continues.