Speaker
Description
The Brazilian ionospheric sector is particularly complex due to the influence of the Equatorial Ionization Anomaly (EIA) and the South American Magnetic Anomaly (SAMA). Also, the large declination angle of the magnetic field and phenomena like disturbed electric fields and plasma irregularities can produce significant spatial and temporal variations in radio communications. Thus, the Maximum Usable Frequency (MUF) may be a key parameter for high-frequency (HF) radio-wave propagation studies, since it represents the highest frequency that can support reliable HF communication over a specified path. Accurate MUF prediction is essential for frequency management, communication planning, aviation, maritime operations, and other HF-dependent systems. Thus, this research aims to characterize MUF variability over Brazil and develop a machine-learning-based framework for short-term prediction under quiet and disturbed ionospheric conditions. Initially, ionosonde observations from Cachoeira Paulista and Boa Vista will be used to investigate regional MUF behavior. The analysis will subsequently be expanded to other Brazilian stations to identify the main physical and geophysical drivers of MUF variability and quantify its response to geomagnetic disturbances. The expected outcome is a validated and regionally adapted prediction framework that contributes to improved HF propagation assessment, space-weather monitoring, and operational ionospheric forecasting over Brazil.