One of the projects at Neumayer that continues virtually year-round consists in measuring the thickness of the sea ice at regular intervals. This layer of ice forms on the open water in the autumn and remains frozen throughout the winter. Only in summer does the ice cover completely or partly disappear for a few weeks or months. The Neumayer Station III itself is perched on a giant ice sheet, the Ekström Ice Shelf, in the midst of the picturesque bay that this blog was named after. The margin between the ice shelf and sea ice is only roughly 10 kilometres from where we’re standing, and though major sections of that borderland form an imposing cliffed coast, near the local penguin colony there are a handful of flat stretches where we can use a snow ramp to reach the sea ice.
Strict rules apply to working on the ice, so as to ensure the safety of the participants; after all, especially in winter, it’s virtually impossible for the station to respond quickly in case of emergency. First of all, the station management has to decide whether anyone is allowed to venture onto the sea ice at all, a choice that is always jointly made with the experts in Bremerhaven. For this purpose, satellite imagery for the past several days and weeks is analysed and the surface structure is closely monitored until everyone involved can rest assured that there are no holes in the ice cover, nor any movements in the ice.
The most important piece of equipment for every excursion is the ‘rescue box’: a red metal container that holds a tent and sleeping bags, gas stove, plates and cutlery, ready-to-eat meals and a first-aid kit, as well as climbing equipment, in case someone should fall in a crevasse. The box is designed to provide emergency aid for up to two people. We can only drive on the ice using snowmobiles and of course never alone. It goes without saying that we have to bundle up in warm clothing, especially since the trip to our monitoring sites, some as far as 20 kilometres away, can take up to two hours. Plus, the whole affair isn’t as cut and dry as it might seem: the sea ice is almost never smooth and level, and jutting mounds formed by ice floes – not to mention countless ridges, known as sastrugi – often block our path, forcing us to take a detour. The same is true for the icebergs we pass along the way.
Once we’ve reached our destination, the measurement always involves the same routine: the scientific coordinator – in our case, meteorologist Michael– selects a point where we first clear away the snow, and then use a special segmented drill, which can be extended as needed, to bore a hole in the ice. The following steps include measuring the atmospheric and surface temperature, collecting water samples and, unless we’re standing on bare ice, measuring the thickness of the snow cover. And lastly, we use a plumb line to measure the sea-ice thickness. We then repeat the procedure at four additional holes, in the four cardinal directions from the first.
We’re nearly always accompanied by the local emperor penguins, which, after a two-month break, began returning to Atka Bay in late April. In the course of the winter, they’ll breed and raise their young here. Curious, they take a casual glance at our equipment and what we’re up to, before returning to their colony.
To date, we’ve taken these sea-ice measurements at three separate sites. The thicknesses varied from 90cm to more than 4 metres, though in the latter case this was probably due to older layers from last year. That explanation seems all the more likely because we had to dig through 80cm-deep snow before we reached the ice itself – which, at temperatures hovering around 35 degrees below zero and with only a few hours of daylight, was no mean feat. But on trips like this one, the participants are rewarded for their hard work with fantastic views of the icebergs in the bay, and the constantly changing colours of the sun, hanging just above the horizon, lends the scenery an almost magical flair.
This last photo was taken a few weeks ago. In the meantime the Polar Night has begun, and the sun no longer rises above the horizon at all. And the night from 21 to 22 June is midwinter: the longest night of the year.