Bjerknessenterets mål er å forstå klima
til nytte for samfunnet.

Seminar talk: Breaking up is hard to do - Simulating extreme sea-ice breakup events in the Arctic

Jonathan Winfield Rheinlænder from the Nansen Environmental and Remote Sensing Centre and UIB will give a seminar talk on November 29



The loss of thick multi-year ice in the Arctic means that the ice is weaker and therefore more easily broken up by strong winds or ocean currents. In recent years extreme sea-ice breakup events have been occurring more frequently, even during the middle of winter when the ice cover is frozen solid.   This may lead to an earlier onset of the melt season and potentially accelerate Arctic sea ice loss. Such extreme events are generally not captured by current climate models - something that could limit our trust in future projections of Arctic sea ice.

In this study we investigated the driving forces behind large sea-ice breakup events during winter and how they will change in the future using a sea-ice model. Our model is the first to reproduce such a breakup event and reveals that the combination of strong winds and thin sea ice are key factors in driving the breakup.  

We found that breakup in winter has large consequences for local air-sea fluxes and leads to enhanced ice production, but also increases the overall movement of the ice cover which makes it more vulnerable. Finally, we show that if the Arctic ice cover continues to thin these extreme breakup events will become more frequent in the future.

Arranged date for the seminar talk: Nov 29, 2021

Portrett Jonathan
Jonathan Winfield Rheinlænder

Short biography:

Undergraduate at the Niels Bohr Institute in Copenhagen working on abrupt climate change in Greenland and Antarctic ice cores.

Went on to do a PhD in Bergen, supervised by Kerim Nisancioglu, Lars Henrik Smedsrud and David Ferreira about the role of ocean circulation and sea ice in driving abrupt transitions in climate.

In 2020 (last year) he started a postdoc at the Nansen Center in the sea ice modelling group. Here he has been working with the neXtSIM sea ice model, focusing on the impact of extreme sea-ice breakup events on Arctic sea ice and climate.

In addition, he holds an Ass. Prof position at UIB developing a new climate course for high school teachers and Norwegian industry.