Automatic Identification System data-potential resource for marine vessels drift studies in the Baltic Sea

Automatic Identification System (AIS) has been employed for increasing the safety at the sea. Nowadays general information about the marine traffic can be tracked in operational mode using www.marinetraffic.com web portal. Additional information can be purchased for commercial and research purposes. Our study highlights a possibility to study the drift using an additional information available at www.marinetraffic.com-selected data on vessel position during its status 'not under command', which corresponds to the drifting vessels. Trajectories of the drift from AIS have been compared with mathematically modeled point-wise drifter paths. Copernicus Marine Environmental Monitoring Service's data for the surface current and Danish Meteorological Institute's model Harmonie data for the wind speed was employed to force the drift model. This comparison may give an indicative insight in the performance of the state-of art drift models. Drift model skill is related to (1) accuracy of the models for the surface current and the wind speed (2) selected drift model and its parameters, and (3) representation of the ship parameters in the drift model. Future research may focus on AIS data application in improving of the accuracy of operational forecasts of the vessel drift for search and rescue (and marina pollution combating) purposes; AIS data may be used for systematic bias (e.g. leeway) correction in operational models.