Combinatorial observation ionospheric characteristics during tropical cyclone Debbie passing eastern Australia in 2017 using GPS and ion sounder

Abstract. The ionospheric morphology responses to tropical cyclone passing over eastern Australia, named as DEBBIE in 2017, is investigated using Global Positioning System (GPS) Slant Total Electron Content (STEC), GPS ionospheric scintillation S4 index and ionospheric characteristics by High Frequency (HF) radio. Based on the data analysis in this study, some significant morphological characteristics of ionospheric responses to tropical cyclone Debbie are identified as follows: a) As the GPS satellites PRN01 and PRN11 were passing above typhoon center, their ROTI (Rate of STEC index) is obviously increased. b) The S4 intensity of the GPS ionospheric scintillation is significantly enhanced on March 27, which mostly concentrate around tropical cyclone center and distribute over the region within 18 °S-25 °S. c) The stronger enhancement of f₀F1 and f₀F2 was observed by High Frequency at Townsville on March 28, when the distance between Townsville and the center of tropical cyclone Debbie was shorter. Regarding the coupling mechanism between the ionospheric disturbance and the tropical cyclone, it is suspected that the electric field perturbations due to turbulent top movement from tropical cyclones might generate ionospheric irregularity and disturbance. To a certain extent, some ionospheric irregularities can further produce bubbles.