Noe mangler i Framstredet...

Havistoktet i Framstredet (havområdet mellom Svalbard og Grønland) er nylig avsluttet og her kan du lese om forskningen som ble gjort underveis og se ferske bilder. Dette var det siste havistoktet til Norsk Polarinstitutt med vårt gamle forskningsskip, RV Lance. Toktleder Laura de Steur har skrevet teksten:

Toktdeltakerne

Toktdeltakerne

Årets deltakere kommer fra Det danske tekniske unviversitet, Universitetet i Edinburgh og Norsk Polarinstitutt samlet på isen foran RV Lance. Foto: Paul Dodd / Norsk Polarinstitutt

Laura de Steur

Laura de Steur

Foto: Elina Nystedt

Lance i isen

Lance i isen

Foto: Laura de Steur / Norsk Polarinstitutt

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Foto: Laura de Steur / Norsk Polarinstitutt

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Foto: Laura de Steur / Norwegian Polar Institute

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Foto: Laura de Steur / Norwegian Polar Institute

Something is missing in Fram Strait...

Laura de Steur, research scientist/oceanography/cruise leader, Norwegian Polar Institute

"I assured Amelie that we would definitely be sailing through heavy ice during the Fram Strait cruise, as is always the case, since the East Greenland Current is the main export route of sea ice from the Arctic. This was when speaking to Amelie as she was preparing an instagram post for the oceanandseaicenpi instagram account well before for the FS2017 cruise. As it turned out, that post had to be changed when we were a couple of days into the cruise. We already saw on sea ice maps prior to leaving Longyearbyen that the whole Fram Strait was ice free this year in August. However, we could not quite believe it until we saw it with our own eyes...

After a day of steaming toward 78°50'N, 0°W where we started our hydrographic (CTD) section across the EGC and the Greenland shelf and where we would collect our 6 oceanographic moorings, we found indeed that our path was not 'paved' with sea ice this time round. It was an exceptional experience to recover the tall (up to 2400 m) moorings from the ocean from this gray and cold ocean. It reminded me of the Irminger Sea in the northwest Atlantic, foggy and gloomy. What happened?! Because of the lack of sea ice this year we could finish the first section and moorings within a week as Lance could keep moving at 10 knots instead of 3 knots when having to break ice. The moored instruments were all recovered in good shape with a huge amount of new and exciting oceanographic (temperature, salinity, and currents) and sea ice data stored in them. These data contribute to the time series that NPI has built of Arctic freshwater and sea ice transport, and ocean temperatures, which is now as long as 20 years. The various water samples and tracer data that are collected on the CTD stations are used to trace back what Arctic source waters feed the EGC which contributes as input to the Fram Centre Arctic Ocean project Trimodal.

Sea ice work is an important part of the Fram Strait Arctic Outflow Observing system, but this year we had to go far west on to the east Greenland shelf and to the north to find suitable sea ice floes to work on. The pieces of ice we did find appeared to be generally thick and very ridged, suggesting that the ice we saw was older ice and not first-year ice. Only on a few occasions did we find sufficiently large floes to moor the ship to, which makes working on the ice much safer and easier. When this was not possible, the sea ice work was done by using the Man Overboard Boat (MOB) from Lance. Closer to Greenland the weather improved, with calmer and sunnier conditions. This allowed us to get also a lot of CTD work done here as well as sea ice work. Freezing temperatures quickly led to newly formed ice in this region, which gave us something extra to sample. We ordered special high resolution satellite images for this region. Comparing the in-situ data with the satellite images allows for improving the interpretation or identification of newly formed ice sea ice on the satellite images. New to the cruise this year was the launching of radiosondes, or weather balloons. These were launched once or twice a day, and data will compared with weather forecasts to see how these could be improved by adding data from these typically data-sparse regions.

Relatively warm surface water in the EGC at the mooring section motivated us to investigate this further upstream at 80°N. Here, we did not find the same conditions, suggesting that perhaps anomalous winds and the ice free conditions have contributed to the presence of this warm surface water. The mooring data shows that warm Atlantic Water reached very far west in the EGC in the 3 months before the cruise. How the atmospheric conditions during the months leading up to the cruise have contributed to this will be investigated when we get back. It certainly looks like 2017 is an interesting year with a lot of regional changes relative to earlier years. If this ice-free Fram Strait in August is the start of a new trend is impossible to say right now. Kristen assures us that he has seen ice free years before in his early years of the Fram Strait cruise about 15 to 20 years ago. It certainly motivates us to study this specific year relative to the earlier years in further detail, and it stresses the importance of monitoring this important gateway of the Arctic Ocean in order to understand how changes in the Arctic Ocean and climate will impact the ocean and climate further south of us."

Relevant links:

http://www.npolar.no/en/projects/fram-strait-arctic-outflow-observatory.html