Ice formation from sea spray is an important process regarding offshore operations in polar regions. Due to its safety risk for vessels and structures it has been become part of operational weather forecasting for half a century. However, while models of different complexity have been formulated to predict icing, their performance is still rather limited. There is a general consensus that one of the causes for this lack in performance is due to the freezing process of sea spray and the largely unknown microstructure of the forming ice. In recent years it has been proposed to include microstructure models to predict sea spray ice growth. However, so far no observations of dendritic structure of spray ice exist. The present project aims to close this knowledge gapin microstructure observations through imaging by nondestructive 3-d X-ray micro-tomography (XRT). Another challenge of marine icing is to understand the influence of different surfaces on the microstructureand properties of sea spray ice. We will perform ice adhesion experiments on different substrates, and also here observe the 3-d microstructure in dependence on growth conditions. Of particular interest in the freezing process of saline ice, its microstrcture and adhesion is the fate of saline brine that is expelled during freezing. Also this process will be studied for the first time by XRT imaging, and making uyse of high spationtemporal resolution at synchrotron radiation facilities, as well as high performance radiography . Our approach will gain new fundemental knowledge of microstructure and adhesion properties of sea spray ice. This is of particular importance for the predictability of ice loads on vessels and offshore structures. The project will also lay the ground for development of feasible coatings/materials of low ice adhesion, of high usefulness in cold regions operations. The project is of particular importance in view of a changing climate and increasing logistics in cold waters.
