Tropospheric Ducting Effects on AIS Signals in the Canary Islands

Abstract

For decades, it has been proven that communication signals experience anomalies in their propagation through the troposphere. One of the main anomalies causes these signals to exceed the radio horizon, enabling very long-distance communications. This phenomenon is known as tropospheric ducting and is due to the confinement of the signals caused by anomalous variations in temperature, pressure, and humidity. Due to their location near the equator, the Canary Islands are prone to the formation of atmospheric ducting. This study combines atmospheric information with AIS (Automatic Identification System) signals from vessels to investigate the formation of ducts between the Canary Islands and the Iberian Peninsula. The results obtained correspond to the year 2017, where two significant months are selected to characterise the ducts: February to represent cold months, and August for warm months. It has been demonstrated that the probability of the occurrence of ducts in warm months is significantly higher than in cold months.