ARCTIC SEA ICE NEWS –Ice Under Duress–

Yet another storm has swirled the air up at the pole. (A Dr. Ryan Maue map from the Weatherbell site; click to enlarge.)

Duress 1 gfs_t2m_arctic_1

Despite the fact it is mid-May, the Pole still has a few small areas colored white in the above map. This represents below-zero temperatures (below -17° Celsius) which is cold enough to freeze over leads of open water formed by the winds. However a swirl of less-cold air is involved, less able to freeze-over leads, and over the Beaufort Sea above-freezing air has been drawn north, which is unable to freeze anything at all.

Because the storm over the Pole was complimented by high pressure towards Alaska, the winds were especially strong over the Beaufort Sea, and even now, as the winds slacken and the storm fades, the ice is moving over 30 cm/s.

Duress 5 arcticicespddrfnowcast

This led to some break-up of the ice in the Beaufort Sea, and an individual making a big deal about it.

Duress 6 CFOuXzaWYAAg9Tj

As it is Sunday, and I have some time to sit back and wander about the internet, I found the time to comment,

The break-up of ice floes in the Beaufort Sea is not uncommon, even in February when temperatures are at minus 40°. All that is needed is strong winds. The current creation-of-leads was caused by roaring winds between high pressure towards Alaska and a low pressure right on top of the Pole. These winds have also created a sort of polynya of open water along the arctic coast by the McKenzie River Delta, as they howl off-shore.

The winds are fading fast, but the WUWT Beaufort-sea-ice-page still shows ice drift of more than 30 cm/s in that area. If you go to the WUWT Sea-ice-page you can scroll down to “Arctic Satellite Imagery” and then zoom in to get the view “Snow White ” posted. Though this view makes you aware of the open water between grinding floes, it doesn’t show you the pressure ridges at the edges of these floes, formed when the floes slam together. If you visit often you will notice that the open water often grows swiftly more and more milky in hue, which indicates the open water is freezing over.

The most recently formed leads in the Beaufort Sea are not currently freezing over, as the off-shore winds are at around freezing, which is not cold enough to freeze salt water. However within the same storm at the Pole are sub-zero (sub -17° degree Celsius) temperatures, and these temperatures are freezing other leads over, even in the middle of May. (I get current polar temperatures by using the “initial” maps of various models such as the GFS or GEM, which I get from the maps produced by Dr. Ryan Maue at the Weatherbell site.)

Another good way to get an idea of the duress the ice is under is to watch the various cameras drifting about up there. “O-Buoy 9” is currently interesting, as it shows that a lead of open water has formed right where ice is piled up and the NRL map shows ice as being ten feet thick.

Duress 4 arcticictnowcast

Duress 3 webcam

It should be obvious that the creation of these leads of open water has little to do with warming, or thin ice, for O-buoy 9 is showing us a lead form where temperatures are still below freezing and ice is thick. Instead we should conclude the creation of leads of open water has everything to do with winds, and the direction the ice is drifting.

(O-buoy 9 will be interesting to watch, as it looks like it has escaped the Beaufort Gyre, and is headed for Fram Strait, which will be its eventual doom, for once ice moves south through Fram Strait it rides a conveyor belt towards eventual dissolution in the Atlantic.)

The question people should be asking at this point involves the fact that, even with a stormy arctic creating more leads and more open water, the PIOMAS volume numbers increase. My guess is that, while the leads are obvious and easy to see from satellite views, the pressure ridges are less easy to see, unless you fly lower in an airplane.

For example, the “larger” chunks of ice in the picture below are the size of the smallest  chips in the satellite view above, and the pressure ridges formed when these chucks of ice slam together, obvious below, are invisible in the satellite view above.

polar leads 305464_original

In conclusion I’d say it is a mistake to try to gauge whether the ice is increasing or decreasing by eyeballing areas of open water, or even by using “extent” graphs, especially when the PIOMAS graph shows increasing volume. Even if there is open water at the Pole this summer, and submarines can surface and take snapshots, in other areas the ice may be piled up in increasing heaps and jumbles. 

We are witnessing a change, and ice under duress, and it should be fun to just sit back and observe.


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