NSIDC 2014 Arctic SIE September minimum: July poll

[Neven]

ATTENTION: There are two polls on the ASIF. One is for NSIDC sea ice extent monthly/September average minimum, the other is for Cryosphere Today sea ice area daily minimum. Make sure you are aware of the difference before voting. You can discuss various extent/area data sets in this dedicated thread.

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This NSIDC extent poll will run for 10 days (until July 11th). Until then you can change your vote. There will be a new poll next month.

Here's how things are currently looking based on data up to June 30th:



These are the September minimums for the last 8 years (in millions km2, found here):

    2005: 5.57
    2006: 5.92
    2007: 4.30
    2008: 4.73
    2009: 5.39
    2010: 4.93
    2011: 4.63
    2012: 3.63
    2013: 5.35

The average for the June poll was 3.95 million km2.

You can use the comment thread below to motivate your choice, but discuss various SIE/SIA data sets in this dedicated thread.

[Neven]

Because of the recent sunny weather in the Arctic, and SIE finally dropping more seriously, I've decided to go one bin lower: Between 4.75-5.0 million km2. In other words, in the 2008 and 2011 region.

I might go lower if this weather keeps up (votes can be changed until July 11th), but I probably won't.

Edit: Sorry, I meant 'Between 4.5-4.75 million km2'!

[jdallen]

Because of the recent sunny weather in the Arctic, and SIE finally dropping more seriously, I've decided to go one bin lower: Between 4.75-5.0 million km2. In other words, in the 2008 and 2011 region.

I might go lower if this weather keeps up (votes can be changed until July 11th), but I probably won't.

I'm just one step below you Neven at 4.5 to 4.75.

My 95% confidence range is 3.5 to 5.25.  I think there is an awful lot of slack left yet in our probabilities.

[OSweetMrMath]

My prediction last month, based on a SARIMA statistical model, was for the September extent to be 4.7 million sq. km. As I said shortly after making my prediction, the extent was higher at the start of June than predicted. The June value came out to be 11.31 million sq km, higher than my prediction of 11.0, but within my 95% confidence interval. I have updated my model prediction using the higher observed extent, and my prediction is now 4.8 million sq km, with 95% confidence interval of 4.1-5.5.

I have voted for the 4.75-5.0 range.

Note, however, that recent extent loss has been large. If this continues, that could make my prediction too high.

[Neven]

I'm just one step below you Neven at 4.5 to 4.75.

That's what I voted too, jdallen. I mistakenly wrote last month's choice of bin. Corrected now.

[Anne]

I'm no expert. I've gone for 4.0 - 4.25.  That may prove conservative. I just think we are in the weird zone - so much heat wandering around taking new opportunities and questionable condition of ice, that models aren't so much help.

[Buddy]

Here is a paragraph from the NSIDC in October of 2012.....after the record low ice extent that year (which was reached on Sept 16th):

The near-record ice melt occurred without the unusual weather conditions that contributed to the extreme melt of 2007. In 2007, winds and weather patterns helped melt large expanses of ice. "Atmospheric and oceanic conditions were not as conducive to ice loss this year, but the melt still reached a new record low," said NSIDC scientist Walt Meier. "This probably reflects loss of multi-year ice in the Arctic, as well as other factors that are making the ice more vulnerable."

[DavidR]

I  have started a thread on the forum to discuss submissions to the Sea Ice Prediction Network.
http://forum.arctic-sea-ice.net/index.php/topic,917.0.html.

My prediction remains at 3.2 M km2, however the events of the past couple of weeks have upped my confidence in a record to  90%.

[slow wing]

So much depends on the weather (mainly) and the currents this month, July, and next month, August, that I simply repeated last month's value and sigma...

This early, I just took the 2012 and 2013 values as minus and plus one sigma, respectively.

So 4.49 +/- 0.86 million square kilometres.

That falls within the "4.25-4.50" bin.

Those 2 years might be considered outliers - 2012 with favourable melt conditions, 2013 the opposite - but I consider there is enough room for unforeseen systematic changes for them to each be at only 1 sigma from the central value.

[icefisher]

The CAA and CAB should hold firm.  Without a return to negative AO, getting under 5M extent is going to require a big storm or a substantial ice transport into the Atlantic.  Neither seems likely to happen at this point.  A low of 4.9-5.1 seems likely.  I am going with 5.04.

[Yuha]

I go up from June by one tick: 4.5-4.75.

Reasons: lowish DMI 80N temps and lack of Fram Strait export.

[cats]

I am sticking with 4.5-4.75, same as last month. 

[Rubikscube]

Struggling to make sense of the latest PIOMAS numbers, a slow melt I can to some extent understand, but the lack of melt during the later part of June seems quite strange. Feel like adjusting my prediction a notch or two upwards after this.

[jdallen]

Struggling to make sense of the latest PIOMAS numbers, a slow melt I can to some extent understand, but the lack of melt during the later part of June seems quite strange. Feel like adjusting my prediction a notch or two upwards after this.

I agree. The PIOMAS reporting is counter-intuitive to what I'm seeing in the satellite imagery, and the modeling I'm mulling over.

Yet, they are the ones with the instruments, and I'm not.  Arctic being its usual chaotic self.  I'm sticking by my previous predictions.

[DavidR]

I  can't see anything in the PIOMAS numbers to cause me to change my prediction of record near 3.2 MKm^2.  There are two  elements to consider in the PIOMAS figures.

1.  One is the volume of ice lost in the extent that  has melted out.  This can be calculated from Chris Reynolds thickness distribution.  According to this, at July 1st, the extent loss was responsible for 3500 Km^3 in 2012 and only  3100 Km ^2 in 2014 To acheive this 2012 had lost 1.33 m of average thickness while 2014 had lost 1.37m.  This is because there was far less thin ice back in April 2014, than in 2012.  So that  explains 400 Km^3 of the extra ice in 2014.
 
2. The second factor to consider is that, in April, there was far more ice, above 3 m thick than in 2012.  It  can be shown from the PIOMAS data that the  thicker the ice the less the melt.   Despite the fact that the ice extent that  has melted out lost up to 1.37 m,  the thickness loss in the remaining ice has been nowhere near that.

It would not  be the least  bit surprising if most of the extra PIOMAS volume is in areas that were more than 2.5 m thick at the start of the season.  As we are unlikely to get an extent that is anywhere near that area, I  doubt that  the June PIOMAS figures have a lot to  say about  the end of season extent.

[ChrisReynolds]

Withdrawn due to an error found by Steven.

[bluesky]

Due to latest PIOMAS result, low level of melt ponds, thicker ice in CAB voting for 4.75 to 5M km2 SIE, breaking 2012 record seems very unlikely, 2007 unlikely as northern hemisphere snow extent does not seem to be as conducive to a dipole anomaly, however SIE should be lower than 2013 as SIE in the Arctic ocean seems significantly lower than in 2013 at this stage. Anyway, I am probably wrong as usual as the Artic is always full of unexpected surprises!

[OSweetMrMath]

Will there be an August poll for the NSIDC extent September minimum (and for the Cryosphere Today area minimum)? I've updated my predictions based on the July data, but I've been waiting for a new poll before posting.

[Neven]

Yes, absolutely! I totally forgot about this (even though I reminded myself a couple of times before Aug 1st). Poll will be up soon, thanks for pointing out, OSMM.