The process of water vapor transport across the tropical transition layer involves both microphysical and convective processes. The bromine budget of the stratosphere can not be reconciled with ground-based bromine measurements using long-lived bromine containing substances alone. In this study we look at the interaction of the water vapor transport processes in the context of very short lived (VSL) bromine species. Lagrangian back trajectories initiated in the stratosphere are generated using ECMWF reanalysis data. A simplified microphysical and bromine chemical box model representation are then calculated along the trajectories. We present the transport of the VSL bromine in a conceptualized form and investigate sensitivities to the general chemical, microphysical and convective processes that result in VSL bromine contributing to the stratospheric bromine budget.