Sara Berglund, PhD student, MISU


Why use a Lagrangian divergence to understand heat and salt changes?


Lagrangian trajectories can be used to trace water parcels in the ocean as well as in the atmosphere. The ocean circulation is partly driven by density differences, caused by heat and salt changes. In an eulerian view, we can look at transport of heat and salt, connect it with the heat and freshwater flux at the surface together with eulerian fields of mixing processes. However, in a Lagrangian view, we can in a simple way specify the water mass(es) we want to trace, and together with this trace temperature, salinity, and density along the trajectories pathways. This makes it possible to compute maps describing where specific water masses are changing their properties, such as temperature and salinity, and further understand what processes that are driving these changes. Here, I will present the Lagrangian divergence and explain why it is such a useful tool for understanding the ocean circulation. The method can be extended to other tracers and will probably be useful for anyone working with ocean or atmospheric circulations.


Thursday April 8, 14:15


Remotely via Zoom - link will be distributed via MISU's seminar email announcement.