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Massive Arctic storm batters sea ice

Posted on 10 August 2012 by Neven

Whoever said watching the Arctic during the melting season is boring, needs to put his glasses on. After a record low reflectivity of the Greenland ice sheet (with accompanying floodings on the west coast of Greenland), the calving of another enormous iceberg from Petermann Glacier, and the general rapid decline of Arctic sea ice despite adverse weather patterns, we can now add to the 2012 melting season bonanza the appearance of a cyclone the likes of which are rarely seen in winter, let alone in summer.

The storm came in from Siberia, intensified and then positioned itself over the central Arctic, reaching sea level pressures of below 965 mb in the storm's centre, engendering 20 knot winds and 50 mph wind gusts:

DMISLPdata source: Danish Meteorological Institute

The storm is now losing its strength and dissipating, but its effect on the sea ice has been enormous so far. In this phase of the melting season when decline starts to slow down, large swathes of sea ice just disappear from one day the next, and the next, and the next (which is why I refer to it as flash melting). It can clearly be seen on this animation of sea ice concentration maps that are updated daily on the Cryosphere Today website, showing the sea ice decline of the past couple of days:


Although technically not all of the ice that disappears on these maps is completely melted (some of it doesn't get picked up by satellite sensors due to clouds and waves submerging ice floes), the gale-force winds displace and break up ice floes, and churn the waters below causing warmer, saltier layers under the thin film of fresh water to mix upwards and melt the ice some more from the bottom. This storm is the worst thing that could have happened to an already weakened and dispersed ice pack.

One development on these sea ice concentration maps that stand out particularly, is the detachment of a large swathe of ice floes from the main ice pack. I've never seen such a thing before, and I wouldn't be surprised if it is unprecedented in the satellite era. But I guess that is what highly unusual Arctic summer storms can lead to.

The effects on the ice pack are also staring to get picked up on sea ice area and extent graphs. The most remarkable decline can be seen on this sea ice extent graph from the Danish Meteorological Institute:


That massive decline will probably get revised upwards in days to come (DMI has said it will be revised), but it is visible on other graphs as well, such as the IJIS sea ice extent graph:IJISSIE20120807

And on the Cryosphere Today sea ice area graph the 2012 trend line has been in first place for the past 38 consecutive days, and 54 of the last 59:CTSIA20120806

It's an amazing sight to see this year's trend line so much ahead of record years 2007 and 2011, at this stage of the melting season. Suffice to say that this year's melting season is well on its way to breaking all records on all graphs out there. It's not a done deal yet, it never is in the Arctic, but chances are greater than ever.

So back to the storm. How unusual is it? Very unusual. The strength, the size, the location, the duration, all of it is highly anomalous. Someone on the Arctic Sea Ice blog proposed to call it the 'Great Arctic Cyclone of 2012', but this can probably only be done in retrospect. For who's to say that we won't be seeing more of these Arctic summer superstorms in the near future? Although scientific research on (mostly winter) cyclones dates back many decades, there are a lot of unknowns when it comes to phenomena such as these, if only because things are changing so rapidly in the Arctic.

This storm saw its genesis in northeastern Eurasia, and that has to do land with snow cover, as explained by this 2006 research paper by NSIDC director Mark Serreze (of Arctic Death Spiral fame):

While there have been no trends in the strength or persistence of the summer cyclone pattern over the period of 1958–2005, it is natural to speculate on its future behavior. Climate models are in near-universal agreement that Arctic warming in response to greenhouse gas loading will be especially strong. Results from the present study suggest that, at least in part, the summer cyclone pattern owes its existence to differential atmospheric heating between the Arctic Ocean and snowfree land. If patterns of differential heating change substantially, such as through earlier springtime loss of snow cover over land, or through changes in the presently strong summer net surface heat flux over the Arctic Ocean as the sea ice cover disappears, this may invoke changes in the summer circulation.

Earlier springtime loss of snow cover on land? It certainly looks like it in recent years:

data source: Rutgers University Global Snow Lab

Another factor is the sea surface temperatures of Arctic waters surrounding the cold ice pack. These have been extremely anomalously warm everywhere except in the Bering Strait and Chukchi Sea this year, and this probably helped the storm feed and sustain itself:

I'm not so sure that we're going to see smaller snow cover and sea surface temperature anomalies in coming years, and so I'm not sure either that we won't be seeing more cyclones of this magnitude. Hopefully not, as it would be the death blow for the ever more fragile ice pack. If the Arctic keeps coming up with unpleasant surprises such as these, an ice-free Arctic in September is a definite possibility before the decade is out. And no one wants to think about all the potential consequences this entails. But we must...

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Comments 1 to 9:

  1. GAC12 The 60-day drop in CT area is still above 6 million km2 -- the 20th time this has occurred during this most amazing melt season. CT area is currently 424km2 below the 1979-2011 linear trend for this date. The DMI animation shows all that Beaufort warmth getting spread out by the storm.
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  2. Posted on 11 August 2012 by Neven Huh? Today is August 9!
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    Moderator Response: [DB] Oops. Fixed.
  3. Haven't you been to Arctic Sea Ice blog, From Peru? Neven is the future. Let me try that again . . . Don't you know that the accelerated sea ice loss has caused a shift in the space-time continuum (new acrocliche: SSTC) centered around the Beaufort Gyre? Neven's post must have traveled through the rift.
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  4. Regarding snow cover anomalies, a subject that gets less headline attention than sea ice anomalies. I will be bolder than Neven and assert that the anomalise for May and for June (graphed in the post) will get more negative. But the anomaly for July will not. This is because the melt has been getting earlier each year and can only continue to do that, reducing May & June snow cover. But by July, the only significant NH 'snow' cover left is now Greenland. See Rutgers map for early July here A graph using Rutger weekly data here (usually 2 clicks to 'download your attachment') shows the beginning of July (week 30) 'minning' out with the beginning of June (week 26) starting it's decline to the same place.
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  5. @4 Ooops. Make that Week 22= start of June (red triangle). Week 26= start of July (pink outline square).
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  6. IJIS sea ice extent has dipped below 5 million square km now, currently at a record low for the time of year, passing the 5M sq km mark at six days before it was reached in 2007, and 11 days before last year (the current 3rd lowest). It's unsettling to watch the graphs and look at the MODIS Arctic mosaic images, to say the least. Much informative talk as ever at Neven's great Arctic blog, but I'll restrict myself to an unscientific Excel estimation of the minimum ice extent from today: It's based on projecting the IJIS extent loss from the current date (yesterday, so as not to include the preliminary IJIS current day data) to the date of minimum. Minimum values are estimated from the losses between the current date and each year's minimum date. For example, 2009 lost ~911,000sq km from 17th August to bottom out on 12th Sept '09, so the estimate based on 2009 data is 12th Sept (day 256) and ~4.03M sq km. Estimates based on the last 5 years are open red circles, the previous four years (2003-2006) are triangles: It looks extremely likely that we'll see a new record this year, as many are forecasting. With losses like any of the last 5 years, the minimum will be close to or below 4M sq km. All sorts of uncertainty with this sort of estimate (not least that the ice lost is now in the central Arctic, rather than round the edges), but it's safe to say that those looking for "recovery" might want to look away for a while...
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  7. Nice PIOMAS Arctic Sea Ice animation (1979-2012) from RealClimate participant Andy Lee Robinson: Props, dude. You're my hero!
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  8. One of the continuing issues that drives me *nutsoid* is the dereliction of duty the MSM has exhibited, regarding effective and truthful reporting of this topic. Media Ignore Record Ice Melt
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  9. Hi Neven, looks like arctic roos is showing record minimum ice area already, with a couple of melt weeks still to go.
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