Arctic Sea Ice Discussion 2015: The Melt Season

[Singularity]

Good points Geordiesnow, hopefully the cold nature of the high will help mitigate the ice losses, shame about the warm air imports though - we are seeing more amplification of the global patterns, and I suspect that if a powerful recurving typhoon in the Pacific comes along in 8-10 days time as per current model output, we could see some funky looking weather patterns for a time late August and into September.

 

A couple of rapidly deepening lows near Siberia on the ECM 00z op run - the second leading to unusually strong winds from there to Svalbard and a little way into the N. Atlantic. Just one possible outcome of course.

[BornFromTheVoid]

On CT, 2015 is now just 32k off the 2013 minimum, 100k off 2014 and 160k off 2009.

 

The negative global sea ice anomaly is now larger than any positive anomaly on record.

[Gray-Wolf]

And , again, I'll remind folks of my concerns as to the 'state' of large sections of the remaining ice? If we are hitting 13' and 14' levels then we only have the hulks of some of the older floes left meaning some 'good looking' ice might well blink out as this thin casing collapses under its own mass leaving 'slush puppie' ice behind ( same area/extent foot print) which will not last until mid sept. Keep a close eye on the C.A.B. ice for sins of sudden concentration drops

[knocker]

As always an interesting blog by Neven

 

http://neven1.typepad.com/blog/2015/08/jenga-july-2015.html

[Singularity]

A fascinating read from Neven.

 

July '15 truly was extraordinary when considered in terms of the dominance of high pressure and anomalously high temperatures combined. Interesting what Neven speaks of near the end - the odds of a July like we had this year increasing in a warming world. Makes sense when the warm air heads poleward - pressure falls more slowly in warm air, so the scope for unusually strong and persistent areas of high pressure is increased (or so I understand it, correct me if I'm wrong).

[BornFromTheVoid]

Using the 5 day mean, we're now below 24 of the 36 previous minima, and with a million km2 of another 7.

 

 

A chance of being below every pre-2007 minimum by this time next week.

[BornFromTheVoid]

Looks like Arctic sea ice area will dip below 2013 in the coming days. Wipneus has the latest CT area at 3.51 million km2 (2 days ahead of the CT website), which is 42k below 2013, 29k above 2014, and 87k above 2009.

[knocker]

Latest NSIDC

 

http://nsidc.org/arcticseaicenews/

[BornFromTheVoid]

We're officially below the 2013 minimum, and just 28k off the 2014 minimum, which we should drop below tomorrow. Below 2009 by the weekend maybe? Then a bigger drop is required to catch the next minimum, 2010.

http://arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html

[knocker]

High pressure would seem to be the order of the day for the next ten days.

Chart weatherbell

 

[BornFromTheVoid]

CT now below the minima of 2014 and 2013, and will be below 2009 tomorrow.

 

Meanwhile, the 5 day average NSIDC extent is now below every minima before 2005.

[BornFromTheVoid]

Latest CT values have us below the 2014, 2013 and 2009 minimum areas(all set in September of their respective years). So even if we lose nothing more for the rest of the summer, we'll still have the 6th lowest area on record.

 

The next minimum to reach, 2010, is 321k off but we'd only need another 120k after that to pass 2007, 2008 and 2011 into 2nd lowest.

[BornFromTheVoid]

ADS extent (old IJIS/JAXA) is now below every pre-2007 minimum, and is just 83k off the 2009 minimum.

[stewfox]

ADS extent (old IJIS/JAXA) is now below every pre-2007 minimum, and is just 83k off the 2009 minimum.

 

But a long way of 2007 , 2011 and 2012.

 

Probably end up 4th lowest in 35 yrs , given the very poor previous winter I'm not sure its unexpected.

Edited August 22, 2015 by stewfox

[BornFromTheVoid]

But a long way of 2007 , 2011 and 2012.

 

Probably end up 4th lowest in 35 yrs , given the very poor previous winter I'm not sure its unexpected.

 

The very poor previous winter? How do you figure that? We started off this summer with the highest volume since 2008 or 2009 didn't we?

[stewfox]

The very poor previous winter? How do you figure that? We started off this summer with the highest volume since 2008 or 2009 didn't we?

 

Extend was poor and we had above arctic temperatures for most of the winter.

 

Volume was better but i don't consider it a good winter for ice growth cf 1980s 1990s or 2000s but I do agree perhaps 'very poor' is perhaps not correct .

Edited August 22, 2015 by stewfox

[BornFromTheVoid]

Extend was poor and we had above arctic temperatures for most of the winter.

 

Volume was better but i don't consider it a good winter for ice growth cf 1980s 1990s or 2000s but I do agree perhaps 'very poor' is perhaps not correct .

 

Ah, now! You were all about how volume was the most important thing at the start of the melt season and late winter extent didn't matter

 

 

I think volume is more important than any short term late season growth (which we didn't see this year)

 

In need and as if often repeated volume is the key

 

 

[Midlands Ice Age]

But a long way of 2007 , 2011 and 2012.

 

Probably end up 4th lowest in 35 yrs ,

Very good point Stewfox.

It was 'expected' by most (certainly the cats and myself), that it would be lower this year, since it had started out with major lowerings of ice in the Siberian side and more ice over the Canadian side (including better volume) with overall the extent being down. The low figure at the start of the melt season almost guarenteed some losses at this point in the season. If we have a better winter season there could wll be further increases next year.

But as usual we will see.

Certainly not a catastrophic melt season (as yet!) but note we still have another 3 weeks of possible melt left.

MIA

Edited August 22, 2015 by Midlands Ice Age

[4wd]

Ah, now! You were all about how volume was the most important thing at the start of the melt season and late winter extent didn't matter

Recent volume trend seems to be continuing.

Not down.

http://psc.apl.uw.edu/wordpress/wp-content/uploads/schweiger/ice_volume/SPIOMASIceVolumeAnomalyCurrentV2.1.png

[BornFromTheVoid]

Recent volume trend seems to be continuing.

Not down.

http://psc.apl.uw.edu/wordpress/wp-content/uploads/schweiger/ice_volume/SPIOMASIceVolumeAnomalyCurrentV2.1.png

 

What do you mean by recent and what do you mean by continuing in this context?

The trend for the whole series is down, the last 30 years is down, the last 10 years is down, the last 5 years is slightly up (not statistically significant), last year is down. The series remains well within the bounds of the long term downward trend.

Edited August 23, 2015 by BornFromTheVoid

[BornFromTheVoid]

ADS extent now just 12.7k above the 2009 minimum. Looking at the losses in previous 12 years between now and the minimum, we see a range from 293k (2006) to 833k (2012) with an average of 623k. This would leave us with a minimum between 3rd and 6th lowest on record, with the average being 4th lowest.

 

Meanwhile, we can expect some significant increases in CT area over the next few days, as melt ponds in the central Arctic begin to partially refreeze. Coverage around the edges are still dropping (as seen in the steady extent losses). This uptick should come to a stop early next week when most melt ponds have refrozen, with a gradual decline then into September.

[Midlands Ice Age]

ADS extent now just 12.7k above the 2009 minimum. Looking at the losses in previous 12 years between now and the minimum, we see a range from 293k (2006) to 833k (2012) with an average of 623k. This would leave us with a minimum between 3rd and 6th lowest on record, with the average being 4th lowest.

 

Meanwhile, we can expect some significant increases in CT area over the next few days, as melt ponds in the central Arctic begin to partially refreeze. Coverage around the edges are still dropping (as seen in the steady extent losses). This uptick should come to a stop early next week when most melt ponds have refrozen, with a gradual decline then into September.

 

BFTV

 

Thanks for all the numbers..

 

You certainly are a wiz with them!!

 

MIA

Edited August 23, 2015 by Midlands Ice Age

[4wd]

Recent volume trend seems to be continuing.

Not down.

http://psc.apl.uw.edu/wordpress/wp-content/uploads/schweiger/ice_volume/SPIOMASIceVolumeAnomalyCurrentV2.1.png

 

 

What do you mean by recent and what do you mean by continuing in this context?

The trend for the whole series is down, the last 30 years is down, the last 10 years is down, the last 5 years is slightly up (not statistically significant), last year is down. The series remains well within the bounds of the long term downward trend.

You seem to have worked it out, I wouldn't describe the recent upturn as 'slight'

It looks more like a reversal should it continue much longer.

[BornFromTheVoid]

 

 

You seem to have worked it out, I wouldn't describe the recent upturn as 'slight'

It looks more like a reversal should it continue much longer.

 

Not sure how the slight positive trend continuing if the -ve anomaly is now increasing? We've gone from having the 8th lowest volume at the start of the melt season to the 5th lowest at the end of July. Surely that's more a sign of continuing the long term downward trend?

 

How is it that a positive warming trend (but not statistically significant) trend from 1998 to 2014 counts as a pause, but a 5 year positive trend (much further from being significant) in ice volume counts as a significant increase?

[Methuselah]

 

 

You seem to have worked it out, I wouldn't describe the recent upturn as 'slight'

It looks more like a reversal should it continue much longer.

If one totally ignores the long-term trend (it's so obvious, it beggars belief) one can see about 50 individual 'recoveries' along that line...It's amazing what fantasies a spot of myopia can induce!