There’s been discussion about a big opening in sea ice, called a polynya, and if it had anything to do with the Russian expedition ship, Akademik Shokalskiy, getting stuck near the Antarctic coast. The answer is not so straightforward. “In the winter, polynyas can close up really quickly,” said Kevin Arrigo, a professor at Stanford University. When they close, whatever is inside may be trapped. Continue reading
Guest post by Mark Serreze, NSIDC Director and Professor, Department of Geography, University of Colorado Boulder
Lately there has been much talk about extreme cold weather in the United States and its connection to the polar vortex. Just what is the polar vortex, and how does it affect the lower latitudes? We asked Mark Serreze, NSIDC Director and a specialist in Arctic climatology, to provide an explanation. Here is his response:
A vortex is a region within a fluid where the flow is mostly a rotational motion around a given axis. The Earth’s atmosphere, while a gas, nevertheless behaves broadly as a fluid. The polar vortex is the region of the atmosphere that contains the hemisphere’s cold air, rotating from west to east. In the Northern Hemisphere, the axis of the rotation is generally located in the Arctic. There is also a polar vortex in the Southern Hemisphere, in which the axis of rotation is around the Antarctic continent. This post discusses the Northern Hemisphere polar vortex, recognizing that the same basic processes work in the Southern Hemisphere. Continue reading
Although Arctic sea ice extent did not set a low record this year, it’s still clear that there is less sea ice than there used to be. Scientists are keeping a close eye not only on the dwindling ice, but also on the ripple effect its loss might have on the rest of the Arctic environment. A big question involves the exchange of heat between ocean and air—and the weather patterns that result. What does current research say about how floating ice—or the lack of it—might be changing the Arctic atmosphere? Continue reading
The Big One
The Great Arctic Cyclone of 2012 lifted out of Siberia on August 2nd, swirling in a counter-clockwise rotation up into the Arctic. As one of the most extreme Arctic cyclones ever recorded, its consumption of an already low sea ice extent raised many concerns. Now Arctic cyclones are garnering attention, but is all the hype warranted?
“People seem to have this thought that all this storminess is unusual,” said Mark Serreze, an Arctic climatologist and center director at NSIDC. “Well it’s not. It simply isn’t. Summer is the time for cyclones.” Arctic summers are not calm. In fact, the months of August and September see a maximum amount of cyclonic activity. Not every summer is very stormy, but overall, the Arctic is the Arctic for a reason. Continue reading
In spite of the massive blizzards that have slammed parts of the northeastern United States, much of the country is experiencing a pronounced lack of snow. And where there is snow, it is less than usual. It follows a very low snow year from the previous season, causing people to worry if low snowfall is the new normal.
A previous Icelights post, Arctic sea ice and U.S. weather, discussed possible causes behind the changes in winter weather, trying to see if there are correlations to larger climate changes. Researchers like Jennifer Francis of Rutgers University are exploring the possibility that declining sea ice in the Arctic is altering atmospheric temperatures and weakening the jet stream. This change may shift the Northern Hemisphere storm track, leaving some places unusually snowy, or leaving normally snowy locations dry. Can a few good blizzards help reverse the snow drought across parts of the United States? Or is this string of dry winters yet another symptom of climate change? Continue reading