Understanding the effects of cloud seeding into tropical Understanding the effects of cloud seeding into tropical cyclones using the ICON Model

This thesis investigates the microphysical and dynamical responses of trop ical cyclones (TCs) to artificial seeding with cloud condensation nuclei (CCN), using high-resolution simulations with the ICON model. Motivated by the hy pothesis that aerosol perturbations can modify convective organization, pre cipitation e!ciency, and storm intensity, a set of idealized experiments was designed to inject CCN into di"erent regions of a developing cyclone: the eye wall, the outer periphery, and the entire storm domain. The analysis focuses on thermodynamic structure, updraft strength, hydrometeor distribution, and precipitation patterns throughout the seeding phase and the subsequent evo lution. The results show that seeding e"ects are sensitive to the injection loca tion. Eyewall seeding leads to enhanced updrafts and temporarily intensified inner-core convection, but reduces rainfall in the outer rainbands. Periphery seeding has the opposite e"ect: it suppresses rainband updrafts and leads to more disorganized precipitation fields. Total-domain seeding produces a mixed response, partially reinforcing cloud water content without consistent storm intensification. Despite these structural changes, the cyclone tracks remain nearly identical across all simulations, and di"erences in total accumulated precipitation are subtle. No evidence is found for a systematic weakening or strengthening of the storm due to CCN seeding alone. This study highlights the complex, non-linear nature of aerosol-cloud in teractions in intense convective systems and illustrates both the potential and limitations of geoengineering approaches to tropical cyclone modification