Fieldwork on the Riiser-Larsen Ice Shelf, East Antarctica, 2025-12-16

Finding everyday life on a floating shelf

In my last post, I wrote about the arduous snowmobile journey from Neumayer to the Riiser-Larsen Ice Shelf. Since then, the days have passed quickly. We have established several camps on different parts of the shelf and started working in earnest.

Routines quickly emerged. Even tall people like Thomas and I have learned to get along in the cramped ark. It is surprisingly comfortable, and we are starting to get the hang of the equipment’s quirks. Our kerosene stoves, for example, have little personalities and require exactly the right mix of air and fuel. Otherwise, they protest loudly and can sound like out-of-tune organ pipes, or in the worst case shoot out a sooty cough straight into the ark. Fortunately, this has not happened to us, but rumours from previous expeditions say it does.

Sun, cold and everyday luxury

We have been fortunate with the weather. A little cloud, a snow flurry now and then, and occasionally some flat light with limited visibility – but overall sunny and almost windless. When the sun is high, it really bakes. Despite using SPF 50+ several times a day, my nose now looks like Rudolph’s.

In the evenings, the sun sets a bit earlier, and the cold becomes more noticeable, especially if the wind picks up. The other day, we woke up to frozen water bottles inside our sleeping bags, but it was barely noticeable thanks to our very comfortable down sleeping bags.

What exactly is an ice shelf?

So what do we do here on the Riiser-Larsen Ice Shelf? And what exactly is an ice shelf?

An ice shelf is the floating extension of the Antarctic ice sheet. When ice that is several kilometres thick reaches the sea, it begins to float and is then affected by ocean movements, tides, currents and coastal weather.

Ice shelves play a crucial role in Antarctica’s mass balance. This is where ice is lost through the calving of icebergs and through melting from relatively warm seawater below. In short, ice shelves are key to understanding how Antarctica contributes to global sea level rise.

The Riiser-Larsen Ice Shelf is the fourth-largest ice shelf in Antarctica, yet it drains only a relatively small sector of the East Antarctic Ice Sheet. This makes it particularly interesting: why does such a large shelf drain so little inland ice, and could that influence its stability? At the same time, it is surprisingly little visited and poorly studied. Logistically, it is also a manageable field site compared with many other parts of East Antarctica.

Meltwater, föhn winds and summer slush

Our work is part of the international iQ2300 project, which aims to calculate Antarctica’s contribution to global sea level rise through the year 2300. This requires advanced computer models, which in turn depend entirely on high-quality field data: snowpack, solar radiation, melting, calving and atmospheric conditions.

Here, the Riiser-Larsen Ice Shelf acts as our Antarctic laboratory. We focus on surface processes that are still poorly understood. During the Antarctic summer, slush lakes – sometimes almost regular meltwater ponds – form on the surface of Riiser-Larsen and other ice shelves. These features are clearly visible in satellite images and have been known for a long time.

A recent study (Mahagaonkar et al., 2025, Earth and Planetary Science Letters) showed that these lakes are likely formed by a föhn effect. Warm air descends from ice ridges towards the shelf, warming the snow and causing it to melt. The meltwater then spreads out over the flat shelf surface. However, this process has so far only rarely been measured directly in the field.

Measuring stations, radar and needle pricks in the ice

Our task is to change this. We are now installing an automated meteorological station on the Riiser-Larsen Ice Shelf. It measures temperature, wind, short- and longwave radiation, snow accumulation and snow temperature down to a depth of 14 metres. The station will remain unmanned for several years, collecting data that can be linked directly to when and how slush lakes form – something we can track using satellite observations.

In parallel, we are running radar profiles that can see 10–35 metres down into snow, firn (multi-year snow) and ice. In this way, we can map snow accumulation much like annual rings in a tree and also identify buried slush lakes that today lie several metres below the surface.

Radar work is time-consuming. We plod along at about 10 km per hour with a snowmobile and a towed antenna, stopping frequently to check data quality and change batteries. On a good day, we collect 20–30 kilometres of profiles. That may sound like little, but on such a vast ice shelf, each profile becomes a valuable pinprick.

Antarctica – a data desert

During a recent climate meeting, a researcher described Antarctica as a data desert. Despite its enormous importance to the Earth’s climate system, we know surprisingly little about what is actually happening there.

In addition to the radar profiles, we therefore make literal pinpricks using a so-called Kovacs drill. It is a hand-operated drill that extracts cylindrical cores from snow, firn and ice. We carefully describe, weigh and measure the cores. They give us a direct answer to what lies beneath our feet and help us interpret the radar data correctly.

It is laborious work. But in a data desert, every data point counts.

Text by: Ola Fredin (NTNU)