The North Sea offers a unique opportunity to use tritium, released from industrial sources such as nuclear power plants, as a tracer for hydrological processes. Nuclear power plants often release tritium in the form of tritiated water (HTO) into the environment, leading to increased tritium concentrations, particularly in coastal areas. These elevated concentrations can serve as an indicator for the spread and transport of water. This thesis analyzes tritium concentrations in samples of rain, water vapor, and surface water from the North Sea to study the transport processes of water vapor. The goal is to identify transport pathways and patterns through statistical analyses and to improve the understanding of the water cycle over the ocean.