Polar bears and vampires? Building a new magnetometer home in Greenland

Throughout the summer of 2024 an intrepid team from DTU Space took to the Arctic climes of Narsarsuaq, Greenland, to install the latest in their portfolio of ground-based magnetometers and a snazzy all-sky camera to keep tabs on the changes in Earth’s magnetic field.

Between icebergs and flower-filled valleys, fjords and gravelly beaches, the task was to survey the site and then build two new houses for the instruments. As you’ll see, in Greenland, there’s a lot to take into consideration.

Not least making your magnetometer house polar bear-proof!

Here’s the story of the campaign, told by Marie, Audrey, Klaus, Jan, Lars and Anna, and at its successful conclusion, a magical musical manifestation of the aurora as it danced over Narsarsuaq, captured on that very same all-sky camera!

Following the sun

Most magnetic field models use both satellite data, such as those of ESA’s Swarm satellites, and ground-based observatory data, which combine beautifully to give both a global and local picture of magnetic field variations.

The more ground-based magnetometers the merrier!

The magnetometers we’ve been installing in Greenland will measure variation of the magnetic field and total magnetic field strength.

The first task fell to Audrey Schillings and Marie Eldor, whose job it was to take measurements of the sun and determine an azimuth mark, and to perform a scalar survey of the site.

They were using equipment like a fluxgate theodolite (not to be confused with the flux capacitor from Back to the Future!), which is an instrument used to measure angles with precision.

For the purposes of Earth’s magnetic field, the theodolite will measure things like the angle difference between magnetic and true north.

The pair spent five days in Narsarsuaq, taking these vital measurements, whilst the foundations were laid ahead of the arrival of Jan and Klaus, who would build the special houses for the magnetometers.

When in Greenland, sometimes you do have to take a bit of time to get close and personal with an iceberg. Have you ever seen one flipping over in real time? It’s quite the sight!

There’s plenty to see besides, when it’s not raining that is… including beautiful flower-filled valleys, the glacial meltwater trickling through them.

Building the magnetometer houses

Klaus Nielsen and Jan Oechsle were the next pair to arrive in Greenland. Eventually… the weather did not make the conditions favourable for landing.

In fact, they had to fly all the way from Denmark and back without touching down because the weather was so bad.

Eventually they made it and were treated to sunshine and flowers before commencing the hard work of building the magnetometer houses!

You have to be careful when making a magnetometer house.

Of course, like any other house, the main job is to keep the elements out. But you can’t go using things like steel nails or doorknobs when you want to measure Earth’s magnetic field.

So, in Narsarsuaq, the nails are made of wood and the doorknobs made of brass.

The nail gun has the advantage of doubling up as a vampire-slaying device Buffy would be proud of.

Another consideration in a place like Greenland is the polar bears, which know very well how to open a door.

And you don’t want a polar bear trundling around the valuable equipment that Lars and Anna would soon be painstakingly setting up.

So, in Narsarsuaq, the door handles are made a little differently. You must lift them up rather than push them down, which is apparently polar bear-proof (for now).

In Denmark, whenever you build a house you have a ‘rejsegilde’ when the underlying structure of the roof is in place.

Rejse, here, means to erect, and gilde means party.

Traditionally, you raise a pine wreath on a stick – we chose something more local (name unknown!). You would also, traditionally, have red sausages at these events, but since they’re disgusting (and we didn’t have any) we settled for local Greenland beer and crisps.

It wasn’t just Jan and Klaus building the house. In fact, there was a five-strong team, who all rightly celebrated their handiwork.

Installing the instruments

The third and final part of the campaign was to install the magnetometers themselves, along with other equipment like an automatic theodolite, and the soon-to-be-famous all-sky camera.

So, as August arrived in Greenland, so did Anna Willer and Lars Pedersen. As did the kit, which was a relief. To celebrate with a welcome drink, there’s no better place to find ice than one of Greenland’s fjords…

First things first, it was important to synchronise with Marie and Audrey’s scalar survey and get the angles right.

The next job was to build the pillars to support the magnetometers. An important task to make sure they’re sturdy and secure.

Funnily enough, the building blocks remind us of something.

It wouldn’t be a Danish building project without a bit of LEGO, would it?

Eventually, the kit was set up, ready to take the pulse of Earth’s magnetic field.

The sky above Greenland also seemed to show its approval.

The all-sky camera was actually on the “nice to do” list, but we’re very glad we did!

As well as spotting some spectacular aurora, Klaus Nielsen also made a stunning sonification of the data as the Green Lady danced overhead, which he did as part of a series for the RumSnak science podcast.

 

Above, a sonification of the northern lights, which you can see dancing above the all-sky camera at Narsarsuaq. (DTU Space/Maple Pools-Klaus Nielsen)

It’s the perfect way to round off the campaign, and celebrate a job well done.

The magnetometers at Narsarsuaq are now another invaluable addition to DTU’s set of instruments throughout Denmark, the Faroe Islands and Greenland that are helping scientists better understand our magnetic field and its local variations.

Thanks to Anna Willer, Lars Pedersen, Klaus Nielsen, Jan Oechsle, Audrey Schillings and Marie Eldor for all their pictures and updates over the summer. Thanks to Klaus Nielsen for the sonification and video. You can find more of his work at his Maple Pools page on Instagram.

You can find out more about DTU’s magnetometers on the DTU Space website.