Analysis of Ionospheric Disturbances Due to Cyclones in Geraldton City of Australia

Abstract A typhoon is a natural disaster that has the potential to cause damage and cause loss of life. On April 2, 2021, the tropical cyclone Seroja formed, reaching typhoon class category 3, which was characterized by a maximum wind speed of 140 km/s on April 11, 2021. Tropical cyclones reached typhoon class when the wind speed exceeded 119 km/h. Typhoon can generate Acoustic Gravity Waves which can cause Concentric Traveling Ionosphere Disturbances (CTIDs). One effort that can be made to mitigate typhoon disasters is to analyze the time when ionospheric disturbances are detected, which can be observed through changes in TEC values by utilizing GNSS technology. The propagation of the GNSS signal from the satellite to the receiver experiences a delay when passing through the ionosphere layer, which can be used to obtain the Total Electron Content (TEC) value. TEC is the number of electrons in a cylindrical vertical column with a cross-section of 1 m 2 along the line of sight. CTIDs due to typhoon Seroja were detected at around 09:00 UTC by GPS 9 at ~0.2 TECU. Interestingly, the CTIDs caused by typhoon Seroja were detected before the typhoon landed in Australia. It is hoped that additional information and variables regarding the comparison of the characteristics of ionospheric disturbances due to typhoons and earthquakes can be used to develop an early warning system for disasters in the future.