Arctic cyclone

Smokey Arctic Cyclone Sets Sights on Central Arctic; PIOMAS Shows Sea Ice Volume 4th Lowest on Record

(Image source: NASA/Lance-Modis)

robertscribbler,

6 August, 2013

A strong, 280 mb Cyclone formed over the Laptev Sea today, pulling in a dense coil of smoke from Siberian wildfires raging to the south and setting its sights along a path that will bring it through waters filled with a slurry of broken ice, passing over the North Pole, and then heading on toward the Fram Strait.

Unlike the Sudden Arctic Cyclone of late July, the new Smokey Arctic Cyclone is strengthening over a region of open water in the Laptev Sea before it begins its passage over a broken ice pack. This will allow the storm to develop more fetch and wave action before it encounters the sea ice. Though not as strong as the Great Arctic Cyclone of 2012, this Smokey storm is likely to pack 25-40 mph winds over large expanses of water and ice, applying wave action to a greatly diffuse and weakened film of thin ice. Though Ekman pumping and mixing of cold surface layers with deeper, warmer layers will likely have some impact on ice — thinning and dispersing it further — it remains to be seen if this storm will be strong enough to have a decisive influence on final melt for the 2013 season.

The storm is, however, moving through an area of very weakened ice even as it pulls a flood of warmer, rougher water along with it. And it remains to be seen what, if any impact, soot pulled in from the Siberian wildfires will have on the ice. Solar insolation is steadily falling as we move on into August. That said, the angle of the sun is still high enough to have some added impact should soot-laden precipitation fall.

The ice state, which has seemed weak and diffuse all summer appears especially vulnerable now

(Image source: NASA/Lance-Modis)

Cracks and large sections of open water riddle the thin ice in a wide stretch from the Chukchi Sea, running through a portion of the Beaufort and then turning on toward the open water in the Laptev. So it will be interesting to see how much this storm affects this section of ice. As the storm is predicted to move on through the Central Arctic and then spend a day or two churning near the Fram Strait, it may also give the thick ice a bit of a late-season nudge.

Party like it’s 2009?

Overall, the storm would have to be a very extreme event to drive the current melt rate to near 2012 levels. Both sea ice extent and area are currently tracking near 2008 and 2009 while sea ice volume, as of mid-July, was just a hair above the third lowest year — 2010. Though it is still possible, given the sea ice’s very fragile state, that 2013 could still hit record lows this year, the likelihood, with each passing day, grows more remote.

PIOMAS Mid-July 2013

(Image source: PIOMAS)

So, at this point, it is worth considering that 2013 may be a counter-trend year. Most of the record heat and warmth associated with human caused warming has been confined to a region of the high Arctic land masses between 55 and 70 degrees north. In this zone, we’ve seen an ominously large number of heatwaves, where temperatures exceeded 90 degrees, along with wildfires spreading above the 60 degrees north latitude line. And though large areas of warmer than normal surface water temperatures invaded the sea ice, air temperatures have been at or slightly lower than average. This is a result of persistent cloudy conditions dominating during periods when solar insolation would have done its greatest damage to the ice sheet. Storms, which at times seemed to drive more rapid melt had the added effect of spreading out the ice, likely contributing to cooler air temperatures. These storms were not powerful enough to provide the energy needed to push 2013 into melt territory. It is also possible that fresh water melt from the Greenland ice sheets — representing a large pulse of about 700 cubic kilometers last year — and from record or near-record snow melts on the continents surrounding the Arctic added some resiliency to the greatly thinned ice in the Beaufort.

These various conditions may be consistent with a combination of natural variability and a potentially emerging negative feedback from melting snow and ice. If 2013 does emerge as a counter trend year, though, it is no indication, as yet, that Arctic melt, overall, has slowed. 2012 was a powerful record melt year and one that occurred under far less than ideal conditions. It is just as likely that natural variability and human forcings will swing back in the other direction come 2014, 2015 or later as happened through the period of 2008 through 2012.

All that said, it is still a bit premature to call the 2013 melt season. We have a storm laden with smoke from the immense Siberia fires on the way and large regions of sea ice remain very fragile. As ever, the Arctic is reluctant to give up her secrets, especially under the assaults of human warming.

Smokey 980 mb Cyclone churns through the Laptev

(Image source: DMI)

Links:

The Arctic Ice Blog

NSIDC