Towards the Fram Strait

As the plane approached Tromsø, we could see the rugged coast line below, with the islands of Lofoten clearly standing out. We landed in bright sunshine, marveling at the beautiful landscape around us. The trip had started at three in the morning when the sound of my alarm clock woke me up, and at four, before the sun had risen, a bus with passengers still half asleep left the Alfred Wegener Institute and headed for Hamburg airport. In Oslo our group met up with those who had flown from Bremen, and soon we were on our way towards Tromsø where the research vessel Polarstern was waiting.

We spent the night in a hotel at the water front, and in the morning I had the opportunity to take a walk along the harbor and across the bridge that connects the island with the mainland. The sun was shining brightly and the scenery absolutely breathtaking.

A bus picked us all up and drove us the short way to the fuel dock where Polarstern was waiting. Inside, we found our rooms and I found out I would was in a room with Laura and Claudia. I never even new that Polarstern had rooms for more than two people, but ours was really nice, with a section for use during the day and a section with beds that was somewhat closed off, making it easier to sleep while others are awake in the main room. This is great because the ship continues working during the night, so those on the night shift will have an easier time sleeping during the day.

It turned out that we would have to stay at the fuel dock until early evening, so we took the opportunity to go back to Tromsø for a couple of hours. It was Sunday, so the only stores that were open were the souvenir shops and the cafes. Laura got a thermo cup with northern light on it, and Claudia got a present for her husband. We went to the Polar Museum, which looked pretty small, but had elaborate exhibitions of the Norwegian early explorers like Nansen and Amundsen, and it displayed the story of the hunters who would over winter on Svalbard to hunt for walrus, polar bear and seals. Crazy lives they had. They had a shop selling books about the Polar ocean, but I didnt find Nansens books about the Fram expedition, which were bought by my great grandmother and I now have at home – it turned out that they were part of the exhibition inside

In the evening Polarstern started moving slowly away from the dock, and soon we were steaming out between the beautiful and majestic Lofoten Islands in the midnight sun. Most people were on the deck above the bridge, but it was cold and windy, and soon there was only a few people left. We entered the Norwegian Sea around midnight and continued northwards towards Svalbard and the Fram Strait.

Polarstern in Bremerhaven

“But where were the polar bears?” We were all on our way back to the car after visiting AWI’s ice breaker, the Polarstern – and Mattis has learned enough about my work to know that Polarstern equals ice and snow, which apparently equals polar bears. But they were not there. We did, however, see a helicopter, labs, sleeping quarters and even a film with penguins – but no polar bears.

For the past couple of years my work has focused on modeling the the Arctic Ocean biogeochemistry, and this summer I will probably participate in a cruise between Svalbard and Greenland. This area is called the Fram Strait, and it’s one of the main gateways to the Arctic, where AWI has monitored the water for several years to help explain how and why the Arctic Ocean is changing.

So when the Polarstern opened its’ doors for the public this weekend, we waited in line for the kids to see where I will go this summer. We actually had to wait in line for 2.5 hours… But Esben and I took turns in the queue, while the kids went around with the other one to check out the many activities. We saw ROV’s filming and taking samples under water, talked to the scientific divers and decorated a Polarstern bag to bring home with us. And for lunch Runa chose a bratwurst of course, we are after all almost real Germans.

And finally, after going through a metal detector and becoming registered we were allowed inside the Polarstern accompanied by our new friends from the long wait. It was nice to show the kids where I worked the last time I went and where I will be this summer. And we talked about the many different nets and machines, had a look in a microscope, saw the helicopter and even the air balloon, which the kids know from a book at home. Esben noted that the bridge had even more instruments than Jensine does, which is rather impressive, and it was cool for them to see where many of the pictures from the Polarstern have been taken.

It’s been five years since I last went on a cruise on the Polarstern. Back then my work focused on modeling Southern Ocean biogeochemistry, and especially the trace metal iron, and I was lucky to go on a 10-week cruise from Cape Town in South Africa to Punta Arenas in South America. My group was responsible for measuring chlorophyll and particulate organic carbon on the way, while others measured nutrient concentrations, oxygen, salinity, temperature etc.  All in all, it gave an overview of the conditions in the ocean when we were there and helped understand how the physics controls the biology to some degree. Apart from the interesting science, it’s quiet a privilege to go to such a special place as the Southern Ocean, and I am sure the next cruise will be another great experience.

A workshop in Potsdam; the Lena Delta

Currently, my work focusses on the Arctic Ocean – that is, the whole Arctic Ocean, a fairly large area. I don’t really focus on the many rivers that supply fresh water to the Arctic Ocean. But in connection with a permafrost conference in Potsdam, a friend and colleague of mine, Vera, arranged a workshop focussing on the Lena River, Lena Delta and Laptev Sea. I thought it would be interesting to join.

In case people are not really familiar with the Lena River or the Laptev Sea, I have embedded a map below.

The Lena River is located in a permafrost region, where the ground is frozen year round. It is the largest of the rivers supplying water to the Arctic Ocean. As the planet is warming, the question is how this area will change, if the water discharge will increase and how the substances it brings with it will affect the Arctic Ocean.

Up until recently, the Russian shelves have been dominated by ice, but in recent years, the ice is breaking up earlier and is formed again later in the season. This means that light can penetrate into the water, which probably mean that more biological production can take place.

But this region is so remote that only a few Russian research vessels visit, and therefore not much is known about the “old normal” or how this is changing. And it is in regions like this that our models can be used to gain more knowledge about what might happen as the ice becomes more scarce.

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The view from my hotel window towards the Telegraphenberg where AWI has offices in Potsdam.

Sea-ice in our model

To understand how the Arctic sea ice is changing and how it affects for example the underlying ocean currents, we work with a global sea ice ocean model (FESOM). For the last few years, a lot of effort has been put into improving the representation of the sea ice in the model. One focus has been on the large cracks – or leads, to use the correct name, that we know exist in reality. These are very difficult to capture in large scale models, but my colleague Qiang has now succeeded in modelling these leads and has put a video of the results on youtube. In this run, the horizontal resolution is 4.5 km in the Arctic Ocean. That’s quiet high.

Changes in Arctic sea ice

I knew that climate change was occurring when I started working at AWI, but I was not aware of how rapidly the temperature is changing in the Arctic or to what extent it has changed the area of the sea-ice.

The thing is, that while temperatures are increasing all over the planet, the increase happens faster in the Arctic than anywhere else; studies show that the mean Arctic temperature in 2010 was 4 degrees C warmer than the average for 1968 to 2010. And 2010 was not a particularly warm year.

The most obvious impact of the rising temperature is that the extent of the summer sea-ice becomes gradually smaller with time. The September sea-ice extend, has almost been reduced by 40% since 1979. The picture below shows had the ice extend has changed since 1950, based on measurements and models.

The decrease in sea-ice does not just change the habitat for the ever popular Polar Bears, the increased freshwater content also changes the  stratification of the water column, which can lead to changes in the ocean advection and mixing, in the nutrient supply, species composition etc. This can in turn further impact the climate in the Arctic but also globally. I guess I will get back to that in another post.

Arctic sea-ice

Mean extent of Arctic sea-ice as measured by satellites and predicted by models. (from NCAR: http://nsidc.org/news/newsroom/20070430_StroeveGRL.html)

Other, and more obvious impacts of the reduced ice cover is, that it opens up for shipping across the Arctic Ocean, shortening the path from Europe to the Asia significantly and introducing hazards such as oil leaks to the Arctic environment. Also, drilling for oil may begin as the ice recedes.

Sea-ice has been continuously measured from space by satellites since 1979. Below I have added a film from NASA showing the record minimum of 2012, comparing it to the average distribution from 1968 to 1995.

The summer sea-ice extend has reached the lowest values in 2007 and 2012. 2016 does, unfortunately, appear to become another year with high Arctic temperatures and low sea-ice extend.