JAXA (ADS) 2021 Arctic SIE September daily minimum: June Poll

[Juan C. García]

The poll is for the minimum Daily Arctic sea ice extent in September 2020, as measured by ADS-NIPR-VISHOP (JAXA).

September mínimums have been:

Date                  Extent
                     (10^6 km2)
1980's Avg.         7.23
1990's Avg.         6.55
2000's Avg.         5.48
2010's Avg.         4.37
Sep 21, 1979      7.04
Sep 13, 1980      7.77
Sep 12, 1981      7.26
Sep 13, 1982      7.33
Sep 16, 1983      7.41
Sep 12, 1984      6.74
Sep 7, 1985        6.71
Sep 6, 1986        7.31
Sep 2, 1987        7.17
Sep 9, 1988        7.25
Sep 9, 1989        6.93
Sep 21, 1990      6.07
Sep 14, 1991      6.43
Sep 6, 1992        7.19
Sep 8, 1993        6.20
Sep 12, 1994      7.02
Sep 30, 1995      6.02
Sep 8, 1996        7.21
Sep 1, 1997        6.52
Sep 10, 1998      6.43
Sep 11, 1999      5.84
Sep 12, 2000      6.04
Sep 17, 2001      6.55
Sep 8, 2002        5.51
Sep 18, 2003      5.93
Sep 11, 2004      5.68
Sep 21, 2005      5.18
Sep 14, 2006      5.63
Sep 17, 2007      4.07
Sep 9, 2008        4.50
Sep 12, 2009      5.05
Sep 17, 2010      4.62
Sep 10, 2011      4.27
Sep 16, 2012      3.18
Sep 12, 2013      4.81
Sep 17, 2014      4.88
Sep 14, 2015      4.26
Sep 7, 2016        4.02
Sep 9, 2017        4.47
Sep 21, 2018      4.46
Sep 17, 2019      3.96
Sep 13, 2020      3.55

Order by lowest to highest:

[oren]

I voted first! Went for 3.25-3.75, thin CAB ice could cause serious problems, and early Siberian heat could mean loss of the reported high volume in the Laptev and ESS. I expect maybe 3-4, so went for the middle of the range. Wouldn't be surprised by a higher result, would be more surprised with a lower one.

Thank you Juan, as always, for opening these polls.

[Forty-first]

I expect the melting to be much weaker than even in 2013. The minimum will be well over 5 million km, and will probably exceed 2005. In 2013, there was not as much landfast ice in the East Siberian Sea as this spring.


Legend of maps.

The brown color is perennial ice.
The green color is one-year-old ice with a thickness of 30 to 200 cm.
The purple color is young ice 10 to 30 cm thick.
Dark blue is young ice thinner than 10 cm
White areas with oblique shading are fast ice.
Blue areas - clear sea without ice.

Site maps
http://www.aari.ru/main.php?lg=0&id=94

[Juan C. García]

Thank you Juan, as always, for opening these polls.

You are welcome, Oren. Time to start the predictions! 
I start with 3.75-4.25 km². Of course, I could change my mind in the following 10 days.

[Brigantine]

3.50 - 4.00

40% weight on 3.80 ±0.60, 40% weight on 3.80 ±1.06, 20% weight on 3.57 ±1.60
Assumed bin chances: (>5.25) 0%; 1%; 2%; 4%; 8%; 15%; 22%; 21%; 13%; 7%; 3%; 2%; 2% (<2.50)

[Paddy]

Going to guess it'll be roughly average for the last five years, with a provisional estimate of 3.75 - 4.25.

[KenB]

3.5 - 4.0

[Stephan]

I selected bin 3.5-4.0 M km²

[uniquorn]

3.0-3.5
I was going to play safe but the Atlantic side break up, lack of Siberian snow, early Laptev melt and a spooky similarity of 2020 ONDJFMA 2m anomaly to 2011, but mostly worse, tipped the balance.

[cesium62]

3.25 to 3.75.

Last year was a typical year: no weird August cyclones nor other unusual weather, just a steady year over year accumulation of heat.  If this year has typical weather, it will come in at about 3.5, just below last year.  But the exact weather is pretty important and can still add or subtract up to 0.5 from that number.

[miki]

No way is ending higher than last year, imho.

[Rodius]

I went for 3.0 to 3.5

And I am hoping no extreme weather events occur to get that result

[jens]

In 2020's I would expect any melting season to end up below 4M km2 at minimum. Of course an exception could happen, but that would be it - an exception.

So a top3 position in the end I'd say. 2021's ability to compete with either 2012 or 2020 I'm on the fence about at this stage.

[Dreaming of when ...]

I went for 4.0 - 4.5. The last 5 years have all been under 4.5M so no reason to think that this year will buck that trend. With part of this year being a La Nina year leads me to think that there shouldn't be a record minimum.

[oren]

Welcome, D.o.w !

[blu_ice]

I also went for 4-4.5

My guess is this will be a rather mediocre melting season with La Nina preventing record temps globally. Also CAA, most of Beaufort and N.A. side of CAB look healthy.

OTOH these days even a weak year will produce below 4.5

[Alumril]

I think with a potential double dip moderate la nina and the low point in the solar cycle (not that the solar cycle impacts much, but every little helps), I think it'll be slightly above 4 this year and next. My guess is 4.25 to 4.75. But I think by 2024/5 we will be beating 2012 without the need for a GAC or GAAC.

[Aluminium]

3.5-4.0

[PragmaticAntithesis]

3.25-3.75

I don't have all that much in the way of reasoning, other than I'm guessing this year will look similar to last year.

[Glen Koehler]

<snip> To equal the 2020 minimum of 3.55 million km2 requires further melting of  7.29 million km2, 9.8% above the 10 year average remaining melt.

     3.25 - 3.75
     2020 had several record warm months plus a prolonged July clear sky period, so it will be tough for 2021 melt weather to match it.  And as somebody else mentioned, 2021 is the nadir of the solar cycle impact on global average surface temperature - a small but important effect globally though it may or may not result in slightly cooler Arctic temperatures.
     But 2021 has one more year of the inexorable march of ASI decline behind it, the rubbly look of the Atlantic front, and what I think is lower thickness in the CAA-NP-GL triangle (esp. near the NP).   I don't think any of the thick ice that piled up in ESS and Laptev during winter 2020-21 is going to survive until September, so that won't add anything to the Sept. minimum Extent.  For those reasons I think the 2021 September minimum JAXA Extent will be near 2020.

[gerontocrat]

Some observations that I doubt help to guide your vote follow.

The 1st image attached is the projections of the minimum.
Average melt from now of the last 10 years gives a minimum of 4.22 million km2.
Average melt from now of the last  5 years gives a minimum of 4.35 million km2.

Also not that in only 4 years of the the last 14 and 2 of the last 10 is remaining melt enough to get the minimum below 4 million km2. The years are 2007, 2008, 2012, and 2020.

Using 10 year average sea ice extent loss day by day from now to minimum gives a daily minimum of 4.28 million km2 on the 13th September. (see second image). This is 350k above the long-term linear trend value of 3.93 million km2 for 2021, and 724k km2 above 2020's minimum.

The plume and daily sea ice extent change graphs attached show how 2012 and 2020 through a couple of super-melts achieved their low results.

So what does one do?
Look at PIOMAS volume? Not a lot of help there.
https://forum.arctic-sea-ice.net/index.php/topic,3522.msg311506.html#new

Assume an average melt year?

Look at sea ice export and the mess of rubble between 85 & 80 North on the Atlantic Front and go for a big melt?

Being a wimp I am going for 3.75 to 4.25. i.e. minimum guess below trend, maximum guess above 10 year average projection.

[Juan C. García]

I start with 3.75-4.25 km². Of course, I could change my mind in the following 10 days.

If we analyze the values that we had on the first 8 days of June, the year 2021 seems to be as normal as the average of 2010-2020. So, betting that ADS (JAXA) is 3.75-4.25M km2 is the safest thing to do. But thinking on the tendency, the true is that we will see lower values on this new decade. The ice is fragile, and we do not know how the weather is going to be in the following months, but I think that I should bet lower than 2010-20 average. If the melt does not happen on 2021, it will happen on the following years.

So, I am changing my vote to 3.5-4.0M km².

One day left to vote or change your vote. 

[interstitial]

Early on in the season I along with others predicted a slow start to the extent numbers that would pick up in the end. This was due to thicker than usual ice along the periphery and thinner ice in the central arctic. As shown on HYCOM. As far as I can tell the season seems to be proceeding as expected. I expect extent losses will start to pick up soon.

[slow wing]

"Between 3.50 and 4.00 million km^2"

Bracketing the past 2 years. Still higher than 2012, which was a big fluctuation down.

[pauldry600]

Missed the boat.

Ill say exactly 4m this year

[Paddy]

These predictions have generally not aged well...

[Alumril]

I think it's close enough to the end of the melt season to claim victory, along with the 2 others who guessed 4.25 to 4.75
Though in hindsight, I'll replace my reasoning with the single word 'clouds'.