Return of the Perfect Melt Storm synoptic

[Gray-Wolf]

In 2007 we saw ice extent/area take a dramatic fall to levels that took folk by surprise. The 'weather' over that melt season provided near perfect conditions to shed ice cover ( high in-situ melt and high export).

In the months following that min we were told that such an event comes around every 10 to 20 years with the two prior to 07' showing the 10 year spacing.

Should the next one respect the 10 year spacing then next Year would bring us the return of that phenomena.

What do folk think about both its return and its impacts should it return?

[Peter Ellis]

I think that you're reading far too much into a rough heuristic.  If I throw a pair of dice, on average I will get "snake eyes" every 36 years.  Someone more knowledgeable than I can put the correct error bars on it, but say for the sake of argument that there's a 95% chance that having thrown snake eyes once, the next one will turn up again in 36 throws +/- 6, i.e. somewhere in the 30-42 throw range.  That does NOT mean I can sit there after 30 throws and say "It's bound to come up again soon".

Unless you have some plausible physical mechanism generating a 10-year cycle, this is pointless mathturbation.

[Jim Hunt]

Unless you have some plausible physical mechanism generating a 10-year cycle, this is pointless mathturbation.

Well, there is this recent paper Peter:

http://rsta.royalsocietypublishing.org/content/373/2052/20140160

Between 1948 and 1996, mean annual environmental parameters in the Arctic experienced a well-pronounced decadal variability with two basic circulation patterns: cyclonic and anticyclonic alternating at 5 to 7 year intervals.

However:

Since 1997 the Arctic system has been under the influence of an anticyclonic circulation regime (17 years) with a set of environmental parameters that are atypical for this regime.

[Peter Ellis]

OK, that says that there used to be a cycle with a period of 10-14 years, but that this cycle stopped 17 years ago and has been stuck in one phase since.

I still don't see how this is sufficiently strong evidence for 10-year "perfect storm" cycle, such that we should wait with bated breath for 2017 to recapitulate 2007.

[jdallen]

OK, that says that there used to be a cycle with a period of 10-14 years, but that this cycle stopped 17 years ago and has been stuck in one phase since.

I still don't see how this is sufficiently strong evidence for 10-year "perfect storm" cycle, such that we should wait with bated breath for 2017 to recapitulate 2007.

Concur, and as others like Jim Pettit have pointed out, the 2012 GAC probably had less of an effect than people give it credit for.

What we wait for now is to see just how much heat the Arctic picked up during peak insolation, and how much gets applied to the ice via bottom melt.  It's now a race between that and the shift in the energy budget back to where it's radiating more out of the top of the atmosphere than is entering it via insolation, evaporation and importation from lower latitudes via storms.

[AbruptSLR]

OK, that says that there used to be a cycle with a period of 10-14 years, but that this cycle stopped 17 years ago and has been stuck in one phase since.

I still don't see how this is sufficiently strong evidence for 10-year "perfect storm" cycle, such that we should wait with bated breath for 2017 to recapitulate 2007.

Concur, and as others like Jim Pettit have pointed out, the 2012 GAC probably had less of an effect than people give it credit for.

What we wait for now is to see just how much heat the Arctic picked up during peak insolation, and how much gets applied to the ice via bottom melt.  It's now a race between that and the shift in the energy budget back to where it's radiating more out of the top of the atmosphere than is entering it via insolation, evaporation and importation from lower latitudes via storms.

Gray-Wolf indicated that if the presumed  10-year cycles are true that we would see the ice extent decline in the summer of 2017 (2007 plus 10 years).  So to disprove Gray-Wolf's hypothesis you are going to need to wait another 14 months.

[Gray-Wolf]

Hi Guys!

it's is not my 'theory' just a concern i've been holding onto since 2007

We have not seen many 'good' years for ice melt/export since 07' ( when compared to 'average' or 'good for retention') so I'm just a tad concerned that 'when' such a synoptic returns it will be the first 'practically ice free year'.

It was not me but the scientists that did all the research on the cycle and it was the scientists who highlighted that the last two , prior to 07' , favoured the 10 year spacing.

I know the planet is changing, i know folk have noted the PDO 'changing' since the start of the 80's so maybe there is a mechanism that has made the 10 year spacing more frequent since the 80's?

To me the 'facts' , as I understand them, are that next year onward we should be open to the chance of a 'perfect melt storm synoptic' setting up again over the basin?

[AbruptSLR]

We have not seen many 'good' years for ice melt/export since 07' ( when compared to 'average' or 'good for retention') so I'm just a tad concerned that 'when' such a synoptic returns it will be the first 'practically ice free year'.

If you are concerned about ice export out the Fram then the dipole indicated by the ECMWF for at least the next 10-days should also be of concern:

http://old.wetterzentrale.de/topkarten/fsecmeur.html

[jdallen]

We have not seen many 'good' years for ice melt/export since 07' ( when compared to 'average' or 'good for retention') so I'm just a tad concerned that 'when' such a synoptic returns it will be the first 'practically ice free year'.

If you are concerned about ice export out the Fram then the dipole indicated by the ECMWF for at least the next 10-days should also be of concern:

Not sure it has the right orientation for good Fram export. Might send stuff towards the Atlantic, maybe.

[Gray-Wolf]

I think there is a huge swath of the top of the Atlantic ready to destroy ice not just the Fram? ( all across to the Russian coast?) so any shunt south by the ice edge will lead to enhanced melt along that front? It is not a matter of a stream stuck along the coast of Greenland?

[DoomInTheUK]

Gray-Wolf,

2017 seems like a decent bet, but not because of some dubious 10 year cycle (with only a couple of data points for validation). The condition of the ice appears to be getting to a stage that it just can't stand up to any storm. If we get another freeze season like last year, then 2017 could well be the year regardless of it having a 'perfect melt storm'.
But this is the Arctic, when has it ever done what we expected in any given year?

[Steven]

it was the scientists who highlighted that the last two , prior to 07' , favoured the 10 year spacing.

Which scientists said that?  It sounds like numerology.  And what exactly do you mean with the last 2 events prior to 2007?  Do you mean 1987 and 1997?  That seems unlikely, as those were unremarkable melt seasons.  For example the sea ice extent in September 1987 was higher than the 1980s average.

[Gray-Wolf]

Maybe you are confusing 'record years' with 'perfect melt storm'?

I am sure I am not the only one to have read the article in autumn 07'?

[Steven]

I am sure I am not the only one to have read the article in autumn 07'?

You didn't post any links or references in this thread, so I'm not sure what "article in autumn 2007" you mean.  Searching on Google, I think your comments are related to this blog post by Jeff Masters from early 2009.  According to that blog post:

... at last month's meeting of the American Geophysical Union, the world's largest scientific conference on climate change, J.E. Kay of the National Center for Atmospheric Research showed that Arctic surface pressure in the summer of 2007 was the fourth highest since 1948. Cloud cover at Barrow, Alaska was the sixth lowest.

This suggests that once every 10-20 years a "perfect storm" of weather conditions highly favorable for ice loss invades the Arctic. The last two times such conditions existed was 1977 and 1987.

So, according to Jeff Masters there was a "perfect storm" of weather conditions in the summers of 1977, 1987 and 2007, "highly favorable for ice loss".  Apparently, what he means is that there was anomalously high pressure over the Arctic during the summer in those years, especially north of Alaska/Canada.  This can also be seen in the graph below, which shows the average sea level pressure in summer between latitudes 70-90°N and longitudes 0-180°W, for each year from 1948 to 2015:




Note that this graph has several spikes in the last few years: 2007, 2009, 2011, and 2015.  Those spikes don't necessarily mean that there was perfect melting weather in each of those years.  Let alone a 10 year cycle.

[Peter Ellis]

And 1977, 1987, 2007 (but not 1997) isn't as clear a periodicity as Jeff made it sound...

[Gray-Wolf]

Thank you so very much for digging that out Steven1 I thought I'd possibly just spent 9 years on a concern from an article I'd never read........ only nightmares!!!

Everything 'Arctic' was very new to me back then and the 08/09 melt seasons were spent explaining to other poster why no 'recovery' was ongoing!!

I take onboard what you and Peter have offered but I still hold to the notion that the longer we go without seeing similar the more likely we are to bump into one?

That is unless the melting so far is messing with the old weather patterns and aiding the development of new ones?

[Peter Ellis]

I take onboard what you and Peter have offered but I still hold to the notion that the longer we go without seeing similar the more likely we are to bump into one?

No, you can't say this. 

If there's no underlying pattern (i.e. hot / high pressure years appear at random), then it's the same logic as saying "Well I haven't rolled a six for a while so I *must* get lucky on the next throw". 

If there is an underlying pattern, then you have to understand the behaviour of that pattern. Jim Hunt pointed to the most recent research, of which the important bit is figure 5f, showing the AOO index.  When the AOO is high, there is high pressure, warm weather and "perfect storm" conditions for Arctic melting.
http://rsta.royalsocietypublishing.org/content/373/2052/20140160


As you can see, there were indeed peaks at around 1977 and 1987, but in fact the Arctic has been stuck in nearly the "perfect" mode for melt for many years now.  It was never a true ten year cycle, and the behaviour of the system appears to have changed and is now less cyclic than it used to be.

That is unless the melting so far is messing with the old weather patterns and aiding the development of new ones?

Well quite.

[Gray-Wolf]

Just as bump to help Plinius find the thread!

[plinius]

Good, the paper produces a mess. Showing a 10 year period on 5 year smoothed data is pretty stark... There will ALWAYS be a period of double the smoothing length perceived on a data set. Pretty embarrassing fact, actually. Fourier analysis on the at least monthly resolved data would have provided a proper answer. Where is it?

The correlation between AO and sea ice is possibly fine, though it suffers from the strong outlier at the end of the period, so they would have had to do a more sophisticated statistical analysis to prove their point.

Not impressed, I typically recommend rejecting papers like that.

[Gray-Wolf]

I think everyone was in a bit of a tizz at the end of melt season 07' plinius so maybe we might give them a bit of slack? In some ways we're still playing 'catchup' with events only explaining ,post event, how such could occur?

The reason I took 'caution' from the article at the time was that I never considered that such an extreme collaboration of Nature would come around again? I am ever more satisfied that the Arctic itself has now 'skewed' things by leaning toward an increasingly stormy June/July/Aug and so keeping high solar crystal clear High Pressure systems suppressed?

That said this year did a number on the pack ( and the Year's not over Yet and Fram is well loaded?) and this is the worse possible go at repairing that damage so will another rotten winter and similar summer see us battling with 2012 anyhow?

As I've realised, you no longer need a perfect melt storm synoptic camped over the Basin from May until Sept to cause problems any more? 10 years did that, 10 years.....

[mhampton]

I think that you're reading far too much into a rough heuristic.  If I throw a pair of dice, on average I will get "snake eyes" every 36 years.  Someone more knowledgeable than I can put the correct error bars on it, but say for the sake of argument that there's a 95% chance that having thrown snake eyes once, the next one will turn up again in 36 throws +/- 6, i.e. somewhere in the 30-42 throw range.  That does NOT mean I can sit there after 30 throws and say "It's bound to come up again soon".

I feel compelled to point out that your error bars are very far off; having thrown snake eyes once, the chance that the next one will occur between 30 and 42 throws (inclusive) is about 13.547%.  (Its the sum of (1/36)*(35/36)^(k-1) for k between 30 and 42, the geometric distribution.)

Edit: Which doesn't detract from your main point.

[plinius]

There are four different questions, I think.
1) Is there a 10-year period? I strongly refute that this paper gives any evidence for that.
2) Does AO influence sea ice extent? Possible, but the paper does not convincingly prove this or show how much.
3) Is there evidence for a fixed weather situation yet? No answer possible from this paper, I cannot buy their statistics.
4) Do we need a perfect melt storm? Depends on what you want - new record, no, 2016 has shown that we don't even need such exceptional weather to get close to a new record. Complete melt-out? No idea, I am lacking the fantasy to imagine weather that currently could kill the ice pressed against the CAA within one single year.

[Gray-Wolf]

After seeing the way our trawl down to solar min has already impacted the pressure patterns affecting the UK this winter sparing us from the storms and shunting them poleward or South of us.

I'm now wondering if 'low solar' could impart effect over the basin by allowing the high pressure blocking to migrate north over spring?

We have at least another 3 years of low solar to go so if we do see more H.P. over the basin this summer then the effect will be more powerful next summer and probably at max effect by 2019?

Maybe this is the rough and ready spacing between perfect melt storms with the average cycle being  around 11 years from low cycle to low cycle?

I think we all know that we no longer need a 'Perfect melt storm' to drop Sea ice to a record low but just how much damage would a high forcing start to melt season create even if the open water then promoted clouds ( with down welling) over high insolation?

[aslan]

I don't think that the 2007 pattern was the perfect storm, nor that we are going to see this pattern again. We are lost in this wild ride and trying to hold on, trying to grab some certainty. We climate change going on, an the sea ice going down, it is far more likely we are going to see more and more a "warm cyclonism" -still baroclinic and cold core in the definition but with rains and mild temperatures-. Heavy downpours in the end can be as much devastating that a good old high pressure area and a sunny summer. This was the case in 2016, and this will probably become a trend. The 2007 pattern implies that subtropical jet and polar jet (or thermally and eddy driven jet or etc..) are still somewhat no far away from where they are supposed to be in the 20th century climate. But jets are moving northward and at one point (as shown by the 2016 pattern), there is no more "room" to put an high over Arctic.

[Gray-Wolf]

I do not know how the low solar anom works but here in the UK the impacts over the last low solar turned pretty chilly as blocking high unleashed the 'Beast from the East' repeatedly!

This period has seen plenty of spotless days on the sun so we are well on our way into low solar over the coming years and I just do not know how strong/complimentary low solar is to current forcings?

impacts over the summer basin are another thing that I have no 'knowledge' of but if we see forcings in lower lats over winter why would that propensity not drift north with the Polar jet as spring/summer arrives?

i'm sure we are both fully in accord over the recent shift to a storm arctic over summer but we have not yet seen this new pack/weather through low solar?

I do know 2010 saw a volume record being set and 2012 being pretty bad for the basin?

[DrTskoul]

I do not know how the low solar anom works but here in the UK the impacts over the last low solar turned pretty chilly as blocking high unleashed the 'Beast from the East' repeatedly!

This period has seen plenty of spotless days on the sun so we are well on our way into low solar over the coming years and I just do not know how strong/complimentary low solar is to current forcings?

impacts over the summer basin are another thing that I have no 'knowledge' of but if we see forcings in lower lats over winter why would that propensity not drift north with the Polar jet as spring/summer arrives?

i'm sure we are both fully in accord over the recent shift to a storm arctic over summer but we have not yet seen this new pack/weather through low solar?

I do know 2010 saw a volume record being set and 2012 being pretty bad for the basin?

.

Look over at Tamino's (Grant Foster) for the magnitude of The anomaly due to solar cycle variation. Small compared to CO2 and water vapor forcing (+/- 0.1C)

[aslan]

Yep but here there is another explanation. Solar has an impact on ozone cycle, Brewer Dobson circulation, and so on the polar vortex (even though there is no sun over the polar stratosphere in winter of course... but more or less Sun modify the ozone cycle and so the Sun is forcing the polar vortex also). This can lead to a northward or southward displacements of the jets. Of course, variations of the global temperature as a consequence is small, but variations in the synoptic pattern can be quite significant. I hear what Gray-Wolf want to say but I'm really not convinced. Impact of the Sun is stronger in Winter than in Summer for one part. And no matter what happens to the Sun, jets are marching northward. Again, I am really not convinced that the 2007 Summer is of any help to forecast what can happen in the near future.

P.S. : As a side-note, there is also some hints that a prolonged low solar activity (over decades or centuries) can increase the frequency of El Niño, and a prolonged high solar activity can increase the frequency of La Niña, but this is rather hypothetical and true for the "old" climate by the way.

[DrTskoul]

As Iong as you don't bring up the X Force from outer space and gamma ray modulation of clouds, we are good I suppose. If you do mention ozone though please show correlation between ozone layer thickness or hole size vs. solar output.

[aslan]

I am not speaking about ozone hole directly, even though it is a related subject. I am only mentioning the fact that there is a link between ozone chemistry, solar activity (and times to times, volcanic eruptions...), and the transport of ozone in stratosphere. And by the way, QBO is also a player of course. Emissions of chlore counpounds is mudding the picture, with the additional effect of a reduced O3 content in stratosphere (linked to a persistant AAO in Southern Hemisphere pecurlary) but this is not the main point. The Brewer Dobson circulation exists and is influenced by the QBO and the Sun, no matter what is going on with ozone depletion. And this can have a significant effect for the polar vortex in the end.

http://www.iup.uni-bremen.de/sciamachy/sparc/downloads/weberrsparc07.pdf
http://www.iup.uni-bremen.de/materials/icacgp/Weber_stratosphere.pdf
www.gps.caltech.edu/~kl/research/proposalreview_Amended.ppt
ftp://ftp.lpl.arizona.edu/pub/lpl/lon/stratosphere/hood_nas11.pdf (very, very, very heavy PDF. To be downloaded, otherwise the browser could hoist the white flag)

And I am not here to discuss pseudo magic theory neither.

(By the way, if you want to muse a bit : ftp://ftp.lpl.arizona.edu/pub/lpl/lon/stratosphere/ )