The progress in knowledge of physical oceanography of the Gulf of Finland (Baltic Sea): a review for 1997-2007

The main findings of studies of the physical oceanography of the Gulf of Finland (GoF, Baltic Sea) during 1997-2007 are reviewed. The relevant updates published in international peer-reviewed research papers and monographs, bearing in mind that a comprehensive overview of the studies up to the mid-1990s, are discussed (Alenius et al. 1998). The discussion with updates on the basic hydrographical and stratification conditions, and progress in the understanding of atmospheric forcing and air-sea interaction, is discussed at first. Advances in the knowledge of basin-scale and mesoscale dynamics are summarised next. Progress in circulation and water exchange dynamics was achieved mostly by means of numerical studies. While the basic properties of circulation patterns in the gulf were known for a century, new characteristics and tools such as water age, renewal index, and high-resolution simulations have substantially enriched our knowledge of processes in the Gulf of Finland during the last decade. The first overview of both status and advances in optical studies in this area, is presented. Awareness in this discipline was significantly improved as a result of in situ measurements. Our understanding of the short- and long-term behaviour of the sea level as well as knowledge of the properties of both naturally and anthropogenically induced surface waves expanded considerably during these ten years. Developments in understanding the ice conditions of the Gulf of Finland complete the overview, together with a short discussion of the gulf's future, including the response to climate change. Suggestions for future work are outlined.