Eye-roller Claim: one year of Arctic data enough to proclaim ‘danger ahead’
From the UNIVERSITY OF TORONTO and the “one year of data is good enough to predict danger when you let science die” department comes this ridiculous study with an equally ridiculous PR headline. Of course, their science was so robust, they had to use a polar bear image in the PR to tug at heartstrings.
Wind, sea ice patterns point to climate change in western Arctic
A major shift in western Arctic wind patterns occurred throughout the winter of 2017 and the resulting changes in sea ice movement are possible indicators of a changing climate, says Kent Moore, a professor of physics at the University of Toronto Mississauga.
Thanks to data collected by buoys dropped from aircraft onto the Arctic Ocean’s sea ice, Moore and colleagues at the University of Washington, where he spent the year as the Fulbright Visiting Chair in Arctic Studies, were able to observe this marked, anomalous shift in Arctic wind patterns and sea ice movement during the winter of 2017.
Their study is published in Geophysical Research Letters.
Usually, the western Arctic has relatively stable weather during the winter; it is home to a quasi-stationary region of high pressure known as the Beaufort High, which promotes “anti-cyclonic” winds that travel in a clockwise direction and move sea ice along with it. By contrast, the eastern Arctic has a more dynamic climate where cyclones are a common winter phenomenon with storms moving from Greenland towards Norway and the Barents Sea.
“Last year, we looked at the buoy tracks in the western Arctic and saw that the sea ice was moving in a counter-clockwise pattern instead and wondered why,” Moore says. “We discovered that storms were moving in an unexpected direction from the Barents Sea along the Siberian coast and into the western Arctic, bringing with them low-pressures that caused the collapse of the Beaufort High.”
Moore and colleagues believe that the low-pressure systems were able to make inroads into the western Arctic because of an unusually warm fall in 2016 resulting in thinner and less extensive sea ice. During the winter, this allowed for more oceanic heat to be transferred to the atmosphere and provided an additional energy source for these storms.
“As a result of this additional energy source, the storms did not dissipate over the Barents Sea, as is usual, and were able to reach into the western Arctic,” Moore says. “We reviewed more than 60 years of weather data from the Arctic and it appears that this collapse has never happened before.”
Generally, the Beaufort High drives sea ice motion throughout the Arctic as well as impacting ocean circulation over the North Atlantic Ocean. Any shift in movement patterns has the potential to affect the climate in these regions, as well as the Arctic ecosystem that depends on predictable areas of open water and ice.
For example, as a result of this collapse, sea ice was thinner along the coast of the Canadian Arctic Archipelago, as well as in the southern Beaufort Sea last winter. Such changes can disturb Arctic food webs, stressing marine mammals and polar bears, especially if they are ongoing.
“If this becomes part of the normal pattern – even if it happens every few years – it will mean that the climate is changing,” Moore says. “We are still exploring all of the specific impacts.”
Collapse of the 2017 winter Beaufort High: A response to thinning sea ice?
The winter Arctic atmosphere is under the influence of two very different circulation systems: extra‐tropical cyclones that travel along the primary North Atlantic storm track from Iceland towards the eastern Arctic; while the western Arctic is characterized by a quasi‐stationary region of high pressure known as the Beaufort High. The winter (January through March) of 2017 featured an anomalous reversal of the normally anticyclonic surface winds and sea ice motion in the western Arctic. This reversal can be traced to a collapse of the Beaufort High as the result of the intrusion of low‐pressure systems from the North Atlantic, along the East Siberian Coast, into the Arctic Basin. Thin sea ice as the result of an extremely warm autumn (October through December) of 2016 contributed to the formation of an anomalous thermal low over the Barents Sea that, along with a northward shift of the tropospheric polar vortex, permitted this intrusion. The collapse of the Beaufort High during the winter of 2017 was associated with simultaneous 2‐sigma sea‐level pressure, surface wind and sea ice circulation anomalies in the western Arctic. As the Arctic sea ice continues to thin, such reversals may become more common and impact ocean circulation, sea ice, and biology.
Plain Language Summary
The warming that the Arctic is currently experiencing has garnered attention in both the popular and scientific press. Indeed the retreat and thinning of the region’s sea ice is one of the most significant and irrefutable indicators of human influence on the climate. In addition to these long term trends, the past several years have seen record warmth and extreme events in the region, such as above‐freezing winter temperatures at the North Pole, that may be harbingers of even more dramatic changes in the future. In this paper, we document a recent and previously unknown consequence of this warming: the collapse of the winter Beaufort High that occurred as a result of the intrusion of North Atlantic cyclones into the western Arctic. This phenomenon occurred, for the first time, during the winter of 2017 and resulted in a reversal in surface winds and sea ice motion across the entire western Arctic. We argue that the extreme warmth during the autumn of 2016 resulted in reduced sea ice extent and thickness in the eastern Arctic that persisted into the winter of 2017 allowing extra‐tropical cyclones from the North Atlantic to intrude into the western Arctic
via Watts Up With That? http://ift.tt/1Viafi3