PhD defence: From snowflake to ice sheet - Climatic drivers of Greenland’s firn


Sea levels are currently rising, which may lead to an increased likelihood of flooding in many parts of the world, as well as a plethora of other problems. One of the biggest contributors to the rise in sea levels is the melting of the Greenland ice sheet. Large portions of the ice sheet are covered by old snow, called firn. During my PhD, I investigated the role that this firn plays on the melting of the ice sheet. Firn acts as a sponge that can absorb meltwater into its pores, which prevents it from running off into the ocean. It is thus important to understand how firn interacts with meltwater, and what may lead to an increase or decrease in firn cover.

We found that the position of the jet stream, a band of strong westerly winds encircling the Northern hemisphere, plays a large role in determining if a region gains or loses firn. This caused firn loss in the beginning of this century, but firn gain after 2012. When meltwater is absorbed into the firn, it can either refreeze into layers of ice, called ice slabs, or be stored inside the firn as a liquid. Locations of firn that hold water year-round are called aquifers. Ice slabs and aquifers impact meltwater very differently, but researchers were not sure what conditions lead to their formation. Our research finds that the amount of snowfall and melt determine whether ice slabs or aquifers form, and that they are likely much more widespread than previously assumed. In a warmer climate, they may appear more often and accelerate ice sheet mass loss.

Start date and time
End date and time
Academiegebouw, Domplein 29 & online (livestream link)
PhD candidate
M. Brils
From snowflake to ice sheet - Climatic drivers of Greenland’s firn
PhD supervisor(s)
prof. dr. M.R. van den Broeke
dr. P. Kuipers Munneke
dr. W.J. van de Berg