NSIDC 2022 Arctic SIE September average: August poll

[Brigantine]

This is the NSIDC Poll for August {June, July polls here}
Not to be confused with the JAXA Poll {June, July, August}

These are the September averages in 2000-2021 (in million km²):

Year      Extent
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        4.79
2019        4.36
2020        4.00
2021        4.92

[Brigantine]

My vote: 4.75-5.25 (back up 1 bin to match my June vote)

Concentration is still a bit high. There's room for dispersion to mitigate some of the remaining melt.
I may edit this prediction lower before voting closes but after thinking more about the ice remaining in Baffin/CAA and weather forecasts. (but likely the vote will stay in the same bin)

Estimated probabilities for each bin:
Mean                                   5.02           (+0.29)
Median                                5.07           (+0.30)
Highest Probability Density 5.10           (+0.25)
95% Confidence Range      4.01 - 5.60 (+0.41/+0.01)

<1.75 <0.01%, 1.75-2.00 <0.01%
2.00-2.25 <0.01%, 2.25-2.50 <0.01%, 2.50-2.75 <0.1%, 2.75-3.00 <0.1%
3.00-3.25 0.1%, 3.25-3.50 0.3%, 3.50-3.75 0.7%, 3.75-4.00 1.4%
4.00-4.25 2.4%, 4.25-4.50 3.7%, 4.50-4.75 8.5, 4.75-5.00 23.6%
5.00-5.25 34.1%, 5.25-5.50 19.9%, 5.50-5.75 4.7%, >5.75 0.7%

[oren]

Thanks for starting the poll.
I've gone for 4.50-5.00.

[gerontocrat]

Here is some data based on actual extent losses to 7th August and the average of the last 10 years sea ice extent losses & gains from now to 30th September.

The NSIDC DAILY extent minimum currently projection is 4.76 million km2.

However, the September Monthly average comes in higher at 5.12 milliion km2, 0.75 million km2 above the long-term linear trend, and 13th lowest in theb satellite record. This is 0.17 million km2 above the September '21 monthly average, which was 12th lowest in the satellite record.

With only 39 days to the average date of the minimum, and on average about 85% of extent losses done, I see little scope for any dramatic change.

So I have plumped for 4.75 to 5.25 million km2.

[The Walrus]

I went with your projection gerontocrat and opted for the 5.0 - 5.5 bin.

[Tom Stedman]

I think 2021/2022 are to 2020 as 2013/2014 were to 2012, then we'll end up with about the same September average as last year.
4.5-5.0 it is.

[Stephan]

I sticked to my predictions of the last months (4.5 ± 0.25 M km²), although actual projections see a higher September average. Let's see how it works out in the end.

[The Walrus]

I think 2021/2022 are to 2020 as 2013/2014 were to 2012, then we'll end up with about the same September average as last year.
4.5-5.0 it is.

Looking more like 2013/2014 every day.

https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/

[Richard Rathbone]

SIPN August report

https://www.arcus.org/sipn/sea-ice-outlook/2022/august

The Pan-Arctic August Outlook median forecast value for September 2022 sea-ice extent is 4.83 million square kilometers, with upper and lower quartile values of 4.6 and 5.0 million square kilometers, respectively.

It looks like the statistical models have moved rather more in response to July data than the dynamic models and are going to do rather better as a result.

[gerontocrat]

Here are ssome images derived from NSIDC Arctic Sea Ice Extent data (one-day, not 5-day trailing average)

The current projection of the September Monthly average (based on average daily change of the last 10 years after 25 August) is 5.05 million km2. This is 0.69 million km2 above the long term linear trend, 13th lowest in the 44 year satellite record, and 0.10 million above 2021.

The plume of projections from the last 10 years gives a September daily minimum of about 4.9 million km2, with a range from the last 10 years remaining losses of 4.7 to 5.1 million km2. To that uncertainty can be added the unusually large area of very low concentration ice North of 80, which could as easily melt out or be cmpacted and as easily have an early re-freeze.

click images to enlarge

[gerontocrat]

Once more (for the last time this melting season), here are some images derived from NSIDC Arctic Sea Ice Extent data (one-day, not 5-day trailing average)

The current projection of the September Monthly average (based on average daily change of the last 10 years after 3 September) is 4.97 million km2. This is 0.62 million km2 above the long term linear trend, 13th lowest in the 44 year satellite record, and 0.02 million above 2021.

The plume of projections from the last 10 years gives a September daily minimum of just over 4.9 million km2, with a range from the last 10 years remaining losses of 4.65 to 4.9 million km2.
The arithmetical calculation (table Extent-1) comes out marginally lower at 7.75 million km2 with a range of 4.6 to 4.85 million km2.

To that uncertainty can still be added the unusually large area remaining of very low concentration ice North of 80, which could easily melt out and/or be compacted and as easily have an early re-freeze.

click images to enlarge

[Brigantine]

[EDIT]
And I have an answer!

From the 1-day extent values up to Sept. 20 [4.756], to get a September average:

A) below 4.750 million km², the remaining 10 days would need to average 4.640 - i.e. 10,000 km² below the apparent minimum, and 72,000 km² below the current 5-day average (Sept 17-21)

B) above 5.000 million km²,  the remaining 10 days would need to average 5.390 - 6,600 km² below 2009 and the 2^nd highest since 2006. From the Sept 20 value of 4.756 this would take a linear century-break increase of 115,300 km² per day, which by Sept 30 would reach on 5.909, slightly above 2006 and the highest value for that date since 2004. (and compared with only 9 century breaks on any of these 10 dates in the last 15 years)

Each of these certainly do not seem likely, but arguably A) is not _quite_ unimaginable. 4.50 - 5.00 voters can be forgiven for cracking the champagne early though

[/EDIT]
-------------------------------------

I'm trying to guess how the more recent data contributes to the sept. avg. projections above made on Sept 5...

Eyeballing, it's looking like 4.8x million km²

How plausible is it still to get a monthly average below 4.75? Above 5.00?

NSIDC DAILY ARCTIC SEA ICE EXTENT:  4,684,000 KM2 as at 18-Sep-2022
[...]
- Extent is  125 k LESS than 2021,

[gerontocrat]

& attached is the latest projection of the Sept 22 monthly average, which comes in at 4.87 million km2.

The graph says to me 4.5 million is impossible, while 5 million is somewhere between highly unlikely & impossible. With 2/3rds of the average now determined by actual data, changes in the last 10 days have a limited effect on the average.

[Brigantine]

Update:

From the 1-day extent values up to Sept. 22 [4.838], to get a September average:

A) below 4.750 million km², the remaining 8 days would need to average 4.590 - i.e. 59,800 km² below the apparent minimum, and 176,400 km² below the current 5-day average (Sept 18-22)

B) above 5.000 million km²,  the remaining 8 days would need to average 5.451 - 18,600 km² above 2013 and the highest since 2006. From the Sept 22 value of 4.838 this would take a linear century-break increase of 153,300 km² per day, which by Sept 30 would reach on 6.064 - 205,000km² above 2006 and the highest value for that date since 2004

Both are unimaginable now. I'm calling it: JAXA minimum is in the 4.50 - 4.75 bin, and NSIDC is in the 4.75 - 5.00 bin.
It's a lucky year for me - it was close but I got 6/6 and especially for August votes, a good year for ASIF in general.

Congrats to the many other winners!
[NSIDC: 8 in June, 8 in July, and 16 in Aug, JAXA: 15 in June, 10 in July, 32 in Aug]

[Richard Rathbone]

6/6 with the same picks each month. Also lucky, because I made my August pick to try to get that 6/6 despite thinking it was the second best pick. 

[gerontocrat]

NSIDC daily extent data gives a September 22 monthly average of 4.87 million km2, 12th lowest in the satellite record, 0.52 million km2 above the longterm linear trend, and 0.08 million km2 below that of September 2021.

The daily minimum was 4.65 million km2 on the 16th September, also 12th lowest in the satellite record, 0.11 million km2 less than the 2021 daily minimum, and 1.31 million km2 above the 2012 record low minimum.

click images to enlarge