Recent Change - Marine Circulation and Stratification

This chapter describes recent change in the circulation and stratification of the Baltic Sea. A recent warming trend in sea-surface waters has been clearly demonstrated by in situ measurements, remote sensing data and numerical models. Trends in sea-surface temperature (SST) for the past three to four decades based on remote sensing data generally agree with trends determined from in situ observations. Models suggest the current warming within the Baltic Sea lies within the range experienced during the past 500 years. The salinity and stratification of the deep waters are strongly linked to the major inflows of North Sea water that occur sporadically and bring high-saline water into the deep layers of the Baltic Sea. The major inflows normally occur during winter and spring and bring cold oxygen-rich waters into the deep basins. Since 1996, large inflows have also occurred during summer, bringing in warm low-oxygen water

An overview of methods to evaluate uncertainty of deterministic models in decision support

There is an increasing need for environmental management advice that is wide-scoped, covering various interlinked policies, and realistic about the uncertainties related to the possible management actions. To achieve this, efficient decision support integrates the results of pre-existing models. Many environmental models are deterministic, but the uncertainty of their outcomes needs to be estimated when they are utilized for decision support. We review various methods that have been or could be applied to evaluate the uncertainty related to deterministic models' outputs. We cover expert judgement, model emulation, sensitivity analysis, temporal and spatial variability in the model outputs, the use of multiple models, and statistical approaches, and evaluate when these methods are appropriate and what must be taken into account when utilizing them. The best way to evaluate the uncertainty depends on the definitions of the source models and the amount and quality of information available to the modeller.Peer reviewe

A theoretical and experimental study of the self-similarity concept

Sisältää myös kaksi muuta artikkelia: Bin Cheng & Jouko Launiainen: A one-dimensional thermodynamic air-ice-water model: technical and algorithm description report Susanna Hietanen: Literature review on microbiology of aggregates originating from phytoplankton bloom

Physical oceanography sets the scene for the Marine Strategy Framework Directive implementation in the Baltic Sea

A challenge of the EU's Marine Strategy Framework Directive (MSFD) is to ensure comparable status assessments for good environmental status (GES) in the European seas. To this end, the role of dynamic oceanographic features affecting GES must be understood. Natural variability is recognized in the MSFD, but only vague advice is available for scientists and managers about how to apply this in the marine strategies. In this paper it is illustrated how physical factors, and their pronounced natural variability, e.g., irregularity of Major Baltic Inflows (MBI), strong and persistent upwelling, and varying ice conditions, affect status indicators and possibly several of the 11 descriptors of GES in the Baltic Sea. It is recommended that these effects are better understood in all regional seas. They may lead to insights that promote adaption of environmental monitoring programmes, as well as re-definitions of GES and other elements of the marine strategy