To understand how the Arctic sea ice is changing and how it affects for example the underlying ocean currents, we work with a global sea ice ocean model (FESOM). For the last few years, a lot of effort has been put into improving the representation of the sea ice in the model. One focus has been on the large cracks – or leads, to use the correct name, that we know exist in reality. These are very difficult to capture in large scale models, but my colleague Qiang has now succeeded in modelling these leads and has put a video of the results on youtube. In this run, the horizontal resolution is 4.5 km in the Arctic Ocean. That’s quiet high.