When will be break PIOMAS 2012 September record of 3,787 km3?

[jdallen]

So, how can we explain that the volume drop is decreasing, on August and September? Any negative feedback that you know, that could explain this behavior?

I'll offer three hypotheses, none of which are exclusive.

1) The drop is decreasing because there is an overall decrease in available ice.
2) The new distribution of ice is such that there is less vulnerable volume after the Solstice.
3) Ice preserving feedbacks (increased moisture/cloud cover, snowfall/increased albedo) decrease late season heat uptake.

[El Cid]

[/quote]
I'll offer three hypotheses, none of which are exclusive.

1) The drop is decreasing because there is an overall decrease in available ice.
2) The new distribution of ice is such that there is less vulnerable volume after the Solstice.
3) Ice preserving feedbacks (increased moisture/cloud cover, snowfall/increased albedo) decrease late season heat uptake.
[/quote]

I think No3. is most important. More moisture=clouds, and clouds make it more difficult to melt the ice during the summer but also make it more difficult for new ice to form in the winter. It is probably no coincidence that we have not seen a new low of September ice volume since 2012, but we have seen new lows in January-March ice volumes. So records were indeed broken but not during the summer.

[Sleepy]

I think No3. is most important. More moisture=clouds, and clouds make it more difficult to melt the ice during the summer but also make it more difficult for new ice to form in the winter.

Feels like home, if those clouds are thick and low-lying.

I'm not up to date on these things but here's from a paper I've saved:
Table1 and Short wave cloud radiative effect, fig2 from here:
https://ntrs.nasa.gov/search.jsp?R=20170003226

[oren]

So, how can we explain that the volume drop is decreasing, on August and September? Any negative feedback that you know, that could explain this behavior?

I'll offer three hypotheses, none of which are exclusive.

1) The drop is decreasing because there is an overall decrease in available ice.
2) The new distribution of ice is such that there is less vulnerable volume after the Solstice.
3) Ice preserving feedbacks (increased moisture/cloud cover, snowfall/increased albedo) decrease late season heat uptake.

Indeed, all three mechanisms. But I think 1+2 should be emphasized, the peripheral seas are becoming more seasonal, losing ice cover earlier and gaining it later. So ice that used to last until August-September is now gone in June-July. Now you have less ice available for melting, and even more importantly it's located in northern latitudes where volume loss is slower.

[crandles]

As June July drops get larger, there is less ice to melt (smaller perimeter/surface area) and in harder locations to melt (further from coasts & river discharge and deeper water that doesn't warm so easily as warm salty water sinks a long way below surface. Also ice tends to move by wind & currents into these areas whereas areas that have opened up tend to be areas where ice moves out in addition to melting to create open areas and albedo fedback.)

In short, the more we have done the easy to melt out areas, the harder the remainder becomes.

I doubt this answer is complete, how many mechanisms do you want?

[A-Team]

Older ice age classes -- which are strongly correlated with ice thickness and so volume -- have been pinching out for decades. A vastly improved new algorithm for that shows the situation is worse than thought, ie almost all the ice is now first and second year. (The 'graduation' date is usually taken as mid-September.) The 01 Oct 17 concentrations are shown below. This affects Piomas because the level of its algorithmic error increases with ice thinness. That's better captured by UB and UH SMOS (or snow-salinity corrected CryoSat) for sub-meter.

Gifs are still not animating because of admin changes (?) so the animation below needs a click. Note some of the very oldest remaining ice was poised for Fram export on this date; very active export did resume later so that ice is gone.

A new tracking algorithm for sea ice age distribution estimation
AA Korosov et al
https://www.the-cryosphere-discuss.net/tc-2017-250/tc-2017-250.pdf

Effect of Snow Salinity on CryoSat-2 Arctic First-Year Sea Ice Freeboard Measurements
V Nandan et al 17 October 2017 DOI: 10.1002/2017GL074506

[jai mitchell]

It is just that it is hard for me to believe that there is not a negative feedback, contributing to slow the ASI melting at August and September.

Specially on 2016, that was breaking all the extent records on the first six months and continued breaking them on October-December. Also, on 2017, that was breaking all the records on volume (that is, from November 2016 to July 2017).

You know what I think, because I already opened the topic Ice melting (Antarctica, Greenland, etc.) as a short term ASI negative feedback .

But let’s make another question:

On PIOMAS volume, we see a tendency to have bigger drops on June and July, as the years pass. But on August and September, the tendency is to have smaller drops.     

So, how can we explain that the volume drop is decreasing, on August and September? Any negative feedback that you know, that could explain this behavior?

The same increased water vapor intrusion that is producing the warmer snowier winters is also producing colder periods during the melt season.

See link here: https://forum.arctic-sea-ice.net/index.php/topic,784.msg42266.html#msg42266

[DavidR]

Came across this interesting study on Ocean Heatwaves that  highlights a heatwave in the North Atlantic from June to August 2012 coinciding with the last big extent decline.  The article suggests that such heatwave will occur about once every  five years. It will be interesting so see if the next  such heatwave coincides with the next big decline in the extent record.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015GL067308

[Sebastian Jones]

Came across this interesting study on Ocean Heatwaves that  highlights a heatwave in the North Atlantic from June to August 2012 coinciding with the last big extent decline.  The article suggests that such heatwave will occur about once every  five years. It will be interesting so see if the next  such heatwave coincides with the next big decline in the extent record.

https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015GL067308

Yes, I came across that too, and at first my thoughts went in the same direction, but then I realized that correlation is not causation, and that maybe the same combination of events that led to the 2012 arctic sea ice crash may have caused the NW Atlantic heat wave.....It is just too complex to draw conclusions! Which does not mean that we should not pay attention to a heat wave off the coast of Nova Scotia this year.