Vertical features of the ionospheric holes during rocket launches observed by the Sanya Incoherent Scattering Radar

Previous observations shows that during rocket launches, the water in the plume released by rockets usually caused a wide range of ionosphere electron density depletion. While a number of publications devoted to the horizontal variations of such ionosphere holes, observation of the vertical features of ionosphere holes has seldom been reported. In this paper, we used the Sanya Incoherent Scattering Radar (SYISR) to observe the vertical variations of the ionosphere hole during two rocket launch events in year 2022. Both the rockets passed through the topside ionosphere over the China South Sea, with an estimated minimum distance of ~100-300 km from SYISR. About ~15 min after the rocket launch, we observed the ionosphere hole with an altitude range of ~200-800 km. The maximum electron density depletion of -20% occurred at ~420 km, with a duration of 2.2 hours. Based on the observations, we discussed the diffusion of water molecules and its influences on altitude distribution of the ionosphere holes during the rocket launches.