NSIDC 2020 Arctic Sea ice extent September average: June poll

[Juan C. García]

ATTENTION: There are two polls on the ASIF. This one is for NSIDC sea ice extent monthly minimum or September average (which is also used for the SIPN sea ice outlook), the other is for JAXA sea ice extent daily minimum [provided by JAXA (ADS-NIPR-VISHOP)].
Make sure you are aware of the difference before voting.

These are the September averages on 2000-2019 (in millions km2):

   Year          Extent
                10^6 km2
1980's Avg.   7.21
1990's Avg.   6.66
2000's Avg.   5.65
2010's Avg.   4.68
2000             6.25
2001             6.73
2002             5.83
2003             6.12
2004             5.98
2005             5.50
2006             5.86
2007             4.27
2008             4.69
2009             5.26
2010             4.87
2011             4.56
2012             3.57
2013             5.21
2014             5.22
2015             4.62
2016             4.53
2017             4.82
2018             4.71
2019             4.32

Edit: Final 2020 result 3.92.

From lowest to highest:

[Juan C. García]

I will start with the 4.0-4.5 million km² on NSIDC September average.

[Phoenix]

4.25 - 4.75

[blumenkraft]

As with the one before, i went with the mainstream bid.

[Stephan]

I think 4.25 ± 0.25 M km² is the most likely outcome. The minimum shall be around 4.0 M km², so the September average might be one bin higher.

[jdallen]

3.75-4.25 million km2, 50% confidence level.

My hunch is my estimate is high.  Much depends on how the weather plays out.  If June starts as hot as currently forecast, I may revise down a bucket.  If July continues June, we will be making a run at the 2012 record.

[igs]

Same here:


3'750'000 - 4'250'000 km2

50% C.L.

[oren]

Voted 4.0-4.5, it's hard to drive down the Sept average too much. 2012 had both freak compaction and a very late minimum. 2016 which was 200k away from breaking 2012's area record came in at 960k above 2012's average Sept extent. Only two years managed to hit my voted range (2007 and 2019), I am betting 2020 will do so as well, because of the early albedo losses and the relatively low volume.

[Bruce Steele]

Voted 4.0-4.5 Same as last years vote. Voted 3.75-4.25 on the JAXA Same as last years vote.
2020 could come in second lowest year on both those polls and still hit in ranges voted.

[Paddy]

Going for "between 4.25 and 4.75", which has been a frequent bracket across previous years

[The Walrus]

Going for "between 4.25 and 4.75", which has been a frequent bracket across previous years

Hard to argue with that choice.  Four of the past five years have been within that bracket, and the only year to ever fall below was the record 2012.

[gerontocrat]

Because,
- September 2020 average trend value is 4.40 million km2,
- May 2020 monthly average came in @ 65k below linear trend,
- the Russkies predict a long hot summer in the Siberian Arctic Ocean and warming Arctic waters in & around North America,

and -

The Central Arctic Sea.
- Remember the trouble PolarStern had finding a decent floe for the Mosaic Project,
- Remember the numerous comments on the fractured nature of the ice pack in Mosaic reports and from that dumb expedition on skis?
- Add to that 2019 was 2nd lowest daily minimum despite not a load of melt in that sea. (c.f. with 2012 & 2016).

So lots of stuff pushing my thoughts down.
But caution tells me 4.0 to 4.5. If I was brave 3.75 to 4.25. Caution won.

[PragmaticAntithesis]

Interesting: the poll appears to be bimodal. There's only one vote for 3.5-4sqMm so far, despite the four bins surrounding that being the most popular.

Either way, I went for 4-4.5sqMm, as it's one bin higher than my JAXA prediction.

<Edit: I misread the numbers. Oops. -PA>

[oren]

I think PA meant the 3.5-4.0 bin, which does have one vote only.

[igs]

I think PA meant the 3.5-4.0 bin, which does have one vote only.

has been corrected, i removed my post, thanks both.

[Juan C. García]

Only 7 hours to vote or change your vote.

Good day to all! 

[blumenkraft]

You too, Juan! 

[Tom_Mazanec]

I see four of us expect this year to be worse than 2012. Since the record that year may have influenced Hurricane Sandy, that is a good red line for "disaster".

[Tor Bejnar]

Hmmm, I count ten votes fully below 2012's 3.57, and several more 'hedging their bets'.

[Tom_Mazanec]

I tried to be conservative. The ranges are a little confusing as they overlap. But if there are ten then that means even more of us expect this year to be in the danger zone.

[Steven]

June 2020 report from the Sea Ice Prediction Network:
https://www.arcus.org/sipn/sea-ice-outlook/2020/june

For the Arctic, the median June Outlook for September 2020 sea-ice extent is 4.33 million square kilometers, with quartiles of 4.06 and 4.59 million square kilometers. To place this year's Outlook in context, the historical record September low was set in 2012 at 3.57 million square kilometers, and the second lowest record was 4.27 million square kilometers set in 2007. This year's projection is close to the 2019 June Outlook, which was 4.40 million square kilometers, and close to the observed September sea-ice extent of 4.32 million square kilometers. For September 2020, only two of the outlooks project sea-ice extent below the historical low record. Thus, there is a consensus judgement against a new record low September sea-ice extent.