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
Polar scientists are celebrating an anniversary of sorts. Thirty-five years ago, sea ice research took a great leap forward. On October 26, 1978, the Scanning Multichannel Microwave Radiometer (SMMR) beamed its first data records back down to Earth. The instrument, pronounced simmer, was capable of mapping global sea ice concentration and extent, giving scientists a more comprehensive look at Arctic and Antarctic sea ice. Thanks to SMMR and its successor remote sensing instruments, scientists now have a long and detailed record of sea ice that helps them understand how sea ice works, and how it is changing.
Fine-tuning the view
Researchers had employed remote sensing to monitor sea ice since the mid 1960s. Microwave radiometers can see through clouds, providing an uninterrupted view of ocean, land, and ice below the overcast conditions that often prevail at the poles. So scientists hoped that the instruments would be able to accurately distinguish between ice and water. But they soon discovered that SMMR, launched aboard the Nimbus-7 satellite, could distinguish between first-year ice and multiyear ice. This distinction is particularly important in the Arctic, which maintains a portion of its sea ice pack from year to year, unlike Antarctica.
In contrast to previous instruments, SMMR was multichannel, which allowed it to better resolve ambiguities in the data. For instance, features that might look similar in one channel may look different in another channel. These distinctions allowed researchers to fine tune their knowledge of the sea ice pack. They could also begin pairing this time series with other observations to see how other phenomena affected both first-year and multiyear ice.
Tracking the time series
Satellite observations have given scientists a direct and consistent source of data year-round from even the most inhospitable polar regions. The Nimbus-7 SMMR operated for only nine years, but it set the pattern for a series of multichannel satellite instruments that continue to capture a record of conditions from decade to decade. Scientists can now monitor concentration and extent, observe when ice forms and melts each year, discern how young or old ice is, and see where winds and ocean currents push it. While there may be no cake or ice cream to celebrate, SMMR’s birthday reminds us how much knowledge we now have about Earth’s polar climates.
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SMMR data at NSIDC
Most people picture the Arctic Ocean as miles upon miles of thick sea ice. This icy expanse has become threatened as Arctic sea ice shifts from mainly old ice to much younger, thinner ice. How does this shift impact the Arctic environment? And what is the connection between the average age of ice found in the Arctic and the overall sea ice decline? Continue reading
After a cool Arctic summer, sea ice at the North Pole has recovered somewhat from last year’s record low extent. While this is a welcome pause in the downward trend of sea ice extent, some are taking it a step further and hailing this rebound as evidence that the Arctic is no longer warming. But does the recent uptick mean that we have entered a period of global cooling? NSIDC scientists point out why we shouldn’t be reading too much into one summer of less sea ice decline. 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