Research on processes in the ocean and the sea ice

In order to understand how the ocean works, the different processes, which together determine the larger-scale picture, are needed to be studied. Many processes take place on a scale that is much smaller than the scale numerical models can resolve, and a way to describe them in the models must be found. Here are some examples of areas that we are studying.

The bottom water in the Baltic Sea may be renewed when denser water from the North Sea is transported through the Sound and the Danish sounds and then further into the various deep-water basins. The size of the maximum volume of the inflows over the sills, and the subsequent mixing with the overlying water masses, is something that the process studies can give an estimate on.

Salinity in Stolpe Channel
A cross-section of salinity in Stolpe Channel showing a well defined bottom layer of dense saline water that is transported eastward (From Borenäs et al., Tellus, 2007)

In order to calculate how the ice cover in the Arctic will develop, complex models that couple the sea-ice-atmosphere system are used. In these models, a number of the processes may be studied in more detail. One may, for example, examine how a change in the inflow of warm Atlantic water affects the Arctic ice extent, or what determines how much of the incoming solar radiation is reflected out again.

Isvall i Bottenviken
Foto Karin Borenäs

There are important processes also at the seabed that affect the overlying water mass. Such a process is resuspension, in which sediment particles from the bottom whirl up and mix with the above-lying water. This can occur naturally by waves and currents acting on the bottoms, but also as a result of human activities e.g. trawling or dredging. The studies are important in order to increase the understanding about the processes that release nutrients from the seabed and thus affect the eutrophication.