By Luisa Bethke
On the 20th of May, Postdoc Maren Lösing, PhD student Jonas Liebsch and I set out to conduct surface ice melt measurements and to install new wires on Sólheimajökull, an outlet of the Mýrdalsjökull ice cap. The sky was blue, the sun was shining and the mood was, in the prospect of a field day in good weather, brilliant (apart from the very early departure time). When arriving at our destination, the heavy drilling gear was sort of evenly distributed amongst us participants and up we went. After some 30-40 min walk in beautiful weather over a glacier with fascinating tephra patterns, we set to work: measuring old wires and their GPS positions and installing new ones.
Here’s a short explanation of the wire principle: Firstly, a hole of about 9-10 m is drilled under more or less little effort into the ice (in case of our last wire not so little). After that, a wire of a known length is lowered into the hole and fixed to a metal frame, wooden stake or any other item that survives the harsh conditions on a glacier. The part of the wire, that is poking out of the hole is measured, and the GPS location is determined. When returning to the location after some time, the additional length of wire that can be measured gives answer to the question of how much surface ice has melted since. Furthermore, by determining the GPS location, we can retrieve the ice velocity. At some point, the wires melt out completely, so new ones always need to be installed to take over, ideally over the whole transect of the glacier to account for different flow velocities: the glacier moves fastest in the center and slowest at the edges due to more friction. Additionally, microclimatic influences like shading vary across the glacier surface.
So, after a day well spent in the field and a new sunburn despite applying sunscreen three times, we left Sólheimajökull behind us and finished the day with a well-deserved pizza and vegan noodles.
