“Summer cyclones” are among the leading causes of ice melting in the Arctic, according to a recent article published in the renowned journal Science. Researchers from Great Britain and the United States have been to Svalbard this summer to investigate the phenomenon in more detail. In 2012, an area the size of Spain melted sea ice after a huge cyclone. It was the warmest summer in the Arctic in 1,800 years. Among other things, the researchers have flown a small plane through the cyclone 15–30 meters above the ground. The plane has been exposed to cyclone winds of up to 100 km/h, and collected data from the storm before it landed again on Svalbard. Marine researcher Morven Muilwijk took turbulence measurements during the Polar Institute’s trip to the North Pole earlier this year. Photo: TRINE LISE SVIGGUM HELGERUD / NORWEGIAN POLAR INSTITUTE Bigger than tropical cyclones Researchers at the Norwegian Polar Institute are working on the same questions. They recently returned from a trip to the Arctic, where, among other things, they expressed concern about the lack of ice at the North Pole. Ocean and ice researcher Morven Muilwijk was among the researchers who took part in the voyage. – There are many processes that contribute to the melting of sea ice, says the researcher. There is a warmer atmosphere, warmer ocean currents, and changes in weather patterns. But it is especially the effect of wind and waves that is associated with great uncertainty into the future. The storms that the foreign researchers have looked at are an important part of this, says Muilwijk. There was unusually little ice in the Arctic when the Polar Institute traveled to the North Pole this summer. Photo: Morven Muilwijk / Norwegian Polar Institute – These measurements can give us more information about how storms and polar low pressure contribute to the decline in sea ice. It can also help to improve the weather models in these areas, says Muilwijk. In Norwegian, a cyclone in this context is called an arctic storm, and a special type of arctic storm is a polar low pressure. – The arctic storms are not as strong in strength as tropical cyclones. But they survive longer, and are much larger in size. They are in the Arctic for several weeks at a time, explains Muilwijk. This is what a tropical cyclone can look like. The cyclones in the Arctic are not as powerful, but larger in scope and longer lasting. The video is from New Caledonia. Can create a domino effect Previously, the storms passed over a thick ice cover. Now that the ocean has opened up, waves and movement are occurring on the surface. This in turn causes the ice to break up into smaller flakes, and melts even faster. – The consequences of these storms can be much greater, says Muilwijk. – More and bigger waves can have dramatic consequences, for example for coastal communities in northern Canada, Alaska and Russia. There, they are already struggling a lot with erosion as a result of thawing permafrost. – And when the ice now disappears and these storms come in and they get more and more waves, it can contribute to destroying these communities, and simply make these areas uninhabitable, he says. But it’s not just the storms that affect the sea ice, it goes both ways, explains Muilwijk. – But it is still unclear how the reduction in the ice cover will affect the storms. It can, for example, affect where these weather systems move and how strong they become, he says. The storms can also affect changes in the sea, which Muilwijk himself is currently researching. – They can reinforce an ongoing process that we call the “Atlantification” of the Arctic, says the researcher. MSS is a so-called “microstructure probe” that is used to measure turbulence in the sea. Turbulence is small and frequent movements, which makes them difficult to measure. Photo: Trine Lise Sviggum Helgerud / Norwegian Polar Institute With this, he is aiming for a development where the Arctic Ocean differs less than before from the northern Atlantic Ocean. Species migrate north and the temperature differences become smaller. The storms help bring up warm water from the depths, which has come north from the Atlantic Ocean. This also melts ice and reinforces “Atlantification” further, explains Muilwijk. What is a cyclone? Photo: HO / AFP A cyclone is an area of low pressure in the atmosphere that is characterized by winds that in the northern hemisphere blow counter-clockwise in a spiral towards the center of the low pressure. In the southern hemisphere, the wind direction is clockwise around the cyclone. Cyclone is a general meteorological term that covers a number of different rotating systems, such as tropical cyclones, extratropical cyclones and tornadoes, and is rarely used without specifying the type of cyclone in question. Eddy formations in temperate zones, such as in Europe, are called extratropical cyclones. These have an extent of approximately 1,000 to 4,000 km and are formed from wave movements in the separation between warm and cold air masses, the so-called polar front. They are normally not as powerful as tropical cyclones. Other types of cyclones are polar cyclones and subtropical cyclones. The latter share some of the characteristics of both extratropical cyclones, tropical cyclones and cyclones that occur in connection with severe thunderstorms, such as tornadoes. A wind system that rotates around a high pressure area is called an anticyclone. There, the air moves in the opposite direction, where the spiral goes out from the center of pressure, and is usually weaker than in a cyclone. May disappear completely The American researcher Steven Cavallo tells Science that cyclones can be the cause of up to 40 per cent of the annual ice melting in the Arctic. Muilwijk says it is not inconceivable that this could be true. But work is still being done to find out how important the various processes that contribute to ice melting are in the various areas of the Arctic Ocean. A Windborne weather balloon hangs in the air over Svalbard. These are among the tools scientists have used to better understand the climate that contributes to ice melting in the Arctic. Photo: WindBorne / WindBorne The Polar Institute researcher says that some models have shown that the Arctic can be ice-free in summer as early as the year 2050. – At the same time, there is some uncertainty in the models, and we are now working to improve these based on the latest the research. Weather and climate models in the Arctic are much worse than elsewhere. Among other things, because there are few measurements from there, especially in winter. – It is difficult to get there. Because even if the Arctic is warming, it is still cold and harsh, concludes Muilwijk.
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Arctic cyclones eat up sea ice in the Arctic – news Troms and Finnmark
