Meet our scientist: Ole Zeising
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Today we speak with Ole Zeising who is working as a glaciologist at the Alfred Wegener Institute (AWI) in Bremerhaven, Germany.
Ole, how did you become interested in studying Greenland?
When I started studying Geophysics at the University of Hamburg (Germany) I always had in mind that some day I would like to work with ice. I was really interested in the range of knowledge: from the internal structure of the earth, to the geophysical instruments. But nothing fascinated me more than exploring the ice sheets of Greenland and Antarctica. In addition to my master courses, I participated in glaciology lectures at the University of Bremen. Since my master thesis at AWI I am specialized in radar instruments, developed for ice sheets/shelves, which were used at the 79° North Glacier (79NG) and that’s why my PhD is part of the GROCE-Project.
What exactly do you contribute to GROCE?
In the GROCE Project I am responsible for determining basal melt rates (melting on the underside of the glacier) of the 79NG. When the ice of the glacier is pushed over the grounding line - the line at which it has last contact to the bedrock - it comes in contact with the ocean. The section of the glacier which is floating on water is known as a glacier tongue. As a result of the heat that the ocean water supplies, the ice at the base of the glacier tongue is melting. We are interested in how large these basal melt rates are, what their spatial and temporal variability are and how they depend on the circulation of the ocean in the cavity below the glacier. This knowledge is necessary to evaluate the stability of the 79NG, which has been counted as one of the most stables ice tongues in Greenland.
Tell us about your most favourite expedition you have joined within GROCE!
One year ago in July 2018 I had the chance to be part of an expedition to the 79NG. From Longyearbyen, Svalbard, a team of two scientists (a colleague and myself), one logistician and one field guide flew to Station Nord, a Danish military station in northeast Greenland, with a Twin Otter aircraft. We flew out again two days later, to a landing position a few kilometres away from the 79NG. Together with a helicopter pilot and a Greenlandic hunter with his dog (for polar bear protection) we set up a small camp on a hill for 17 days.
What was your most favourite moment during the expedition?
From the first moment I flew with the helicopter from the camp to the glacier I was completely impressed by the size and the beauty of the 79NG. Before, I only knew of alpine glaciers, but they are tiny compared to the dimensions of the 79NG which is 20 km wide and 70 km long. On both sides it is bounded by mountains. Some of these mountains have their own small glaciers flowing onto the 79NG. Flying over the glacier and looking downward onto the surface showed the beauty of meltwater lakes and the variety of shape and colour from of the pure blue water!
What was the main scientific outcome?
We completed ground penetrating radar measurements at locations where colleagues of ours had taken the same measurements the year before. The radar waves are bounced back from different anomalies in the ice and from the ice-ocean/ ice-bedrock interface. By comparing both measurements at each surface spot I will determine basal melt rates to figure out how large and how variable the basal melt rates are. Furthermore, we collected data from four radar stations, which measured autonomously for the whole year to investigate the temporal variability. Both data sets are not fully analysed yet.
Is there a common public misconception in your field that you would like to clarify?
Melting at the bottom of a floating glacier is a normal effect due to heat supply from the warm ocean and it is, in general, not related to climate change. Only in the case of a changing melt rate as a consequence of warmer ocean currents can we link this to climate change.
And the final question: what are you most passionate about within your work?
Most of the time I work in my office writing codes to analyse data, which I really enjoy. Then there have been weeks of preparing for my expeditions and of course carrying them out in Greenland. Being on the ice sheet or the glacier that I have been investigating for a long time and knowing every spot from satellite images gives my work another dimension, since I can then see and feel the ice and sometimes even the extreme temperatures.