JAXA extent minimum 2024: July poll

[Steven]

This poll is about the JAXA sea ice extent daily minimum for 2024.  The minimum is usually reached in mid-September.  Below is a list with the minima for previous years (in million km²) ranked from low to high.

year    minimum
2012    3.18
2020    3.55
2019    3.96
2016    4.02
2007    4.07
2023    4.14
2015    4.26
2011    4.27
2018    4.46
2017    4.47
2008    4.50
2022    4.52
2021    4.61
2010    4.62
2013    4.81
2014    4.88
2009    5.05
2005    5.18
2002    5.51
2006    5.63
...

[oren]

Thanks for starting the poll. It appears Juan is taking a (well deserved) break.
I've gone down one notch to 3.50-4.0, following the widespread and continued surface melt in the High Arctic, and the weakness of the CAA and Beaufort due to relative lack of thick ice.
Kara and Chukchi are lagging but they normally come around by September.

[Stephan]

I stay with my 4.00 ± 0.25 M bin.

[John_the_Younger]

Staying with 'record or near record' 3.0-3.5
(I usually keep my votes secret.)

[Freegrass]

I'm sticking with a big storm and a new record below 3 million km²
Between 2.75 and 3.25 million km²

[Bruce Steele]

Sticking with my June vote 3.5-4.0.  Waiting for the Beaufort to melt followed with something to stir it around.

[gerontocrat]

& I stick with 4 to 4.5 million km2.

[Paul]

I'm also sticking with my original vote(4.0-4.5) however unlike in June where I was tempted to go one higher, I was thinking of going one lower but I'm just hoping the lack of apparent dispersion can counteract any late momentum that we saw last year. Also hoping the relatively slow start compared to some years may also play a role aswell.

[HapHazard]

I went with the correct choice, 3.75 <> 4.25

(haha Honestly if I'm wrong I bet it'll be because I bet too high)

[johnm33]

Following a prolonged period of high mslp we're now looking at the reverse. That enhanced by the new moon tidal cycle should increase the inflow through Bering, exit through Fram, lift the ice in Lincoln easing it's break-up and exit through Nares. The pressure on the arctic side of the CAA will increase and the mixing inflow from the Pacific should create openings north of ESS and on the European side of Lomonosov. The water outflow through Fram will prevent any ice recirculating through the pinch point beteen the pole and N.Greenland/Ellesmere leaving any ice beyond the reach of that current to meet it's demise in a warming Beaufort. Increasingly warm incoming from the Atlantic will soon flow down StAnna warming Laptev allowing the ice to rotate past S.Z. and oin the outflow into the Greenland sea.
I'm tempted to drop a box [or two] but will stick with a conservative 3

[KenB]

I'll stick with 3.75 - 4.25, although I'm a bit tempted to drop one spot lower.  We'll see.

[jdallen]

Atypical of me in recent years, I’m betting on lower numbers than I would normally - 3.25 - 3.75.

It’s a complete gut hunch.  I’ve got nothing quantitative to explain it, just the sense I have of wide-area thicknesses under a meter, massive amounts of heat arriving in the region, wide-scale persistent melt ponding, and impressions the weather isn’t going to break well for the ice any time soon.

It may be on the high side of my estimate, but I think it could go quite a bit lower, if conditions continue to line up as they have.

[SteveMDFP]

Atypical of me in recent years, I’m betting on lower numbers than I would normally - 3.25 - 3.75.

It’s a complete gut hunch.  I’ve got nothing quantitative to explain it, just the sense I have of wide-area thicknesses under a meter, massive amounts of heat arriving in the region, wide-scale persistent melt ponding, and impressions the weather isn’t going to break well for the ice any time soon.

It may be on the high side of my estimate, but I think it could go quite a bit lower, if conditions continue to line up as they have.

Concur.  I think widespread melt ponding at a time of peak insolation is an ominous set-up.

[Killian]

My vote is really conservative, 3.75-4.25, because the indicators are really contradictory from my POV. While the various ice measures have been relatively high, Kris van Steenbergen posted two images in this thread that are really extreme: https://x.com/KrVaSt/status/1809125352112894437

One shows T2m anomalies and the Arctic is going to potentially be getting very, very warm anomaly-wise. The other shows ice thickness reductions recently, up to July 3rd. Good lord...

Based on the second, virtually all the ice outside the central basin and north of NA is 1.5m thick or less. If accurate, it will all melt out leaving an area well below 4M sq km just eyeballing it. Add in the July, August, and Sept rising anomalies, and we could see well below 4M this season, even as the overall numbers look *relatively* robust this week.

2024 is a real headscratcher. I could see anywhere from a new record to 4.25 - though I think 4M is the real top end here.

I think all of this is setting us up for a truly scary 2025 season.

[be cause]

  having been the 1st to vote 2.75-3.25 (again) , I see I now have more company than any other year . I assume I must have voted too high . Less than 2.5 is looking more and more possible .

 oops .. my june vote was 2.5-3 . Vote corrected !

[The Walrus]

Interesting how the guesses compare to the data.  The average minimum over the past 5 years, 10 years, or since 2007 is all about 4.4 - no change over the past 15 years or so (except for annual fluctuations.  The guesses average 3.75 (assuming bin midpoint), significantly lower than the data. 

Currently, JAXA extent is 12th lowest (per gerontocrat), which if continued on its current pace would be above 4.5 (2022 is currently 11th lowest at 4.52).  Consequently, based on historical and current data, I voted for 4.25-4.75.

[Steven]

Currently, JAXA extent is 12th lowest (per gerontocrat), which if continued on its current pace would be above 4.5 (2022 is currently 11th lowest at 4.52).

Indeed, it's remarkable that only 1 person in this poll voted above 4.5 million km2 so far, even though gerontocrat's extent trajectory projection is currently pointing at 4.5.

But extent at this time of year is a poor predictor of the mimimum.  Remember last year in early August when daily extent was 14th lowest for the date.  And yet the 2023 minimum ended up as 6th lowest.  So the extent trajectory projection performed poorly, in contrast to the June+July averaged surface melt indicators which predicted a 5th lowest minimum last year.

For 2024, June was warm and there are indications of strong surface melt in the last few weeks.  On the other hand, the heat in recent weeks is often focused over the same area (Laptev Sea), while the Pacific side of the Arctic is getting far less heat.  Anyway I still have a few days to decide whether or not to stick with my June vote of 3.5-4.0 or not...

[sadmird]

I went with my rpevious quess around 4M mark (3.75-4.25M), although I am thinking about lowering the estimate because it gets apparent that going below 4M becomes more and more plausible as the melt season progresses, positioning of the ice suggests it.

[The Walrus]

Currently, JAXA extent is 12th lowest (per gerontocrat), which if continued on its current pace would be above 4.5 (2022 is currently 11th lowest at 4.52).

Indeed, it's remarkable that only 1 person in this poll voted above 4.5 million km2 so far, even though gerontocrat's extent trajectory projection is currently pointing at 4.5.

But extent at this time of year is a poor predictor of the mimimum.  Remember last year in early August when daily extent was 14th lowest for the date.  And yet the 2023 minimum ended up as 6th lowest.  So the extent trajectory projection performed poorly, in contrast to the June+July averaged surface melt indicators which predicted a 5th lowest minimum last year.

For 2024, June was warm and there are indications of strong surface melt in the last few weeks.  On the other hand, the heat in recent weeks is often focused over the same area (Laptev Sea), while the Pacific side of the Arctic is getting far less heat.  Anyway I still have a few days to decide whether or not to stick with my June vote of 3.5-4.0 or not...

Not to mention that 9 (20%) voted for a new (or near) record low.  Definitely highly skewed. 

On the opposite side, extent was quite low at this time in 2021, with a steeper trajectory.  2021 finished tied for 13th lowest.  I do expect the final minimum to dip below 4.5, but am not convinced that it will penetrate 4.25.

[gerontocrat]

Currently, JAXA extent is 12th lowest (per gerontocrat), which if continued on its current pace would be above 4.5 (2022 is currently 11th lowest at 4.52).

Indeed, it's remarkable that only 1 person in this poll voted above 4.5 million km2 so far, even though gerontocrat's extent trajectory projection is currently pointing at 4.5.

But extent at this time of year is a poor predictor of the mimimum.  Remember last year in early August when daily extent was 14th lowest for the date.  And yet the 2023 minimum ended up as 6th lowest.  So the extent trajectory projection performed poorly, in contrast to the June+July averaged surface melt indicators which predicted a 5th lowest minimum last year.

For 2024, June was warm and there are indications of strong surface melt in the last few weeks.  On the other hand, the heat in recent weeks is often focused over the same area (Laptev Sea), while the Pacific side of the Arctic is getting far less heat.  Anyway I still have a few days to decide whether or not to stick with my June vote of 3.5-4.0 or not...

Not to mention that 9 (20%) voted for a new (or near) record low.  Definitely highly skewed. 

On the opposite side, extent was quite low at this time in 2021, with a steeper trajectory.  2021 finished tied for 13th lowest.  I do expect the final minimum to dip below 4.5, but am not convinced that it will penetrate 4.25.

Since my business used to be mostly about numbers, here we go.

My simplistic projection of the sea ice extent minimum from today's JAXA data gives a minimum of 4.47 million km2, 10th lowest in the 46 year satellite record.

However, the projection from NSIDC sea ice area data gives a minimum 5th lowest in the satellite record. Applying that to JAXA extent data would give a minimum of around 4.07 million km2.

The reason? - very low concentration, currently 2nd lowest in the satellite record for the Arctic sea ice as a whole, and perhaps more importantly, for the High Arctic. Low concentration is associated with low minima, both as a general trend and for individual years. (images 1 & 2)

This suggests to me that the current simple projection of the JAXA extent minimum is too high, that eventually sea ice extent loss will catch up at least partly with sea ice area loss.

A contraindication is Albedo warming potential, especially in the High Arctic, which is very low due to the slow start to the melting season in the High Arctic. No matter how extreme sea ice area losses are from now, cumulative AWP will almost certainly be below recent years. (images 3 & 4)

Based on these numbers the chances of a below 4 million lm2 minimum seem to me to be very low, and for a record low almost at vanishing point.

So I am sticking with 4 to 4.5 million km2, and the minimum to be 4.2 million km2.

[interstitial]

Six months out and their is no correlation between the maximum and minimum extent. The probability and degree to which deviations from averages occur declines with time. We are now about 2 months from a minimum. There is still some time for surprises but the window is closing quickly. I am with Gerontocrat this time I do not anticipate the minimum dropping below 4 million. If the albedo anomaly was larger earlier in the season their would be greater possibility for downside surprises. The location of remaining ice does point to the potential for some downside surprise the question is as always is the magnitude of the variations. As Gerontocrat pointed out 4.5 is the standard so I guessed 4-4.5 million kilometers minimum JAXA extent for 2024.

[Glen Koehler]

    Changed my vote from 3.75 - 4.25 to 4 - 4.5 because, even though my point estimate of about 4.1 remains unchanged and fits within both bins, I want to be right about something today.  With a greater chance of going above 4.25 than below 4.0, 4-4.5 becomes the safer bet.

[John_the_Younger]

Who wants to be right when they can be pessimistic?

[The Walrus]

Who wants to be right when they can be pessimistic?

Just like the media; bad news sells.

[gerontocrat]

3 days of high sea ice extent losses and my simplistic projection of the minimum drops from 4.50 to 4.37 million km2.

Will such high sea ice losses be sustained or is it a 3 day blip?

[The Walrus]

Looking over the past four years, shows four different scenarios.  2020 and 2021 showed higher melt during July, but finished with significantly different minima.  Similarly, 2022 and 2023 had much lower melt during July, and finished with different minima.  Interestingly, 2021 and 2022 had almost the same minima. 

To add to the post by interstitial, the correlation between the ice at summer solstice and autumnal equinox is rather poor.

[Freegrass]

3 days of high sea ice extent losses and my simplistic projection of the minimum drops from 4.50 to 4.37 million km2.

Will such high sea ice losses be sustained or is it a 3 day blip?

Baffin, ESS, Kara, and Beaufort/Chukchi have lots of poof ice for the coming days, so I think large extent losses will continue for a few more days.

[Steven]

24 hours left to vote in this poll, or to change your vote.

[Glen Koehler]

     Looking again at the top ranked years helpfully posted at
https://forum.arctic-sea-ice.net/index.php/topic,4233.msg404408.html#msg404408
year    minimum
2012    3.18
2020    3.55
2019    3.96
2016    4.02
2007    4.07
2023    4.14
2015    4.26
2011    4.27
2018    4.46
2017    4.47
2008    4.50
2022    4.52
2021    4.61
2010    4.62
2013    4.81
2014    4.88
2009    5.05

     It has been 12 years since the 2012 debacle and I am still mystified.  I know about the GAC, and I should re-read the post mortem analyses, but what the heck happened in 2012?  It still is a shocker.  Loose recollection tells me that even up to mid-July, the brewing disaster was not apparent in the usual melt progression charts. 

    But by September, except for an honorable mention in 2020, no other year has come within striking distance of 2012.  An amazing outlier event.  Even so, I think its stand-alone status won't last much longer.

[The Walrus]

Plotting those values yields the following.  Based on the trend, the 2024 minimum would be just under 4.2.  For fun, I drew two lines showing the convergence of the higher and lower values (removing the "outliers").

Last chance to change your vote.

[oren]

But by September, except for an honorable mention in 2020, no other year has come within striking distance of 2012. 

Not so, don't forget 2016, which by area was not far from 2012. It did have a GAC too, though.
I think the GAC explains a lot, it destroyed much ice and also pulled up lots of heat from below, which also explains why 2013 and 2014 were poor melt years (and maybe 2016's GAC also explains 2017).
But this goes beyond the scope of this thread.

[Steven]

     It has been 12 years since the 2012 debacle and I am still mystified.  I know about the GAC, and I should re-read the post mortem analyses, but what the heck happened in 2012?  It still is a shocker.  Loose recollection tells me that even up to mid-July, the brewing disaster was not apparent in the usual melt progression charts. 

There is a thread about this here, discussion about 2012 may fit better there:
https://forum.arctic-sea-ice.net/index.php/topic,3796.0.html

TLDR: the August GAC played a role but I think the main culprit was the strong preconditioning in the months before.  NSIDC area for June 2012 is still the lowest on record for June, and July 2012 is second lowest for July, just a hair above July 2020, so there was a lot of surface melt going on in those two months.

[Glen Koehler]

There is a thread about this here, discussion about 2012 may fit better there:
https://forum.arctic-sea-ice.net/index.php/topic,3796.0.html

Thanks!  Great discussion there. Did not mean to hijack the poll thread, curiosity overtook me.   

[Steven]

Did not mean to hijack the poll thread, curiosity overtook me.   

No problem.  The poll is closed now anyway, so it doesn't hurt to have some general discussion here.  I've also copied the above comments to the 2012 thread.

The latest weather forecasts look favorable for ice retention, with a cold cyclone over most of the Arctic Ocean for an entire week.  This may put the brakes on the melting.

[Iceburn]

I'd say itl finish at 4.7m but I seem to be alone. Seems slow this year and peak melting over. Rest of season drops less by the day.

[Steven]

3 days of high sea ice extent losses and my simplistic projection of the minimum drops from 4.50 to 4.37 million km2.

One week later, that projection is down to 4.14 million km2:

Average remaining extent loss (of the last 10 years) would produce a minimum in September 2024 of 4.14 million KM2

NSIDC area is even 3rd or 4th lowest for the date (for 5-day or 1-day, resp.) and would correspond to a JAXA extent minimum just below 3.75 million km2, using linear regression.

But maybe extent losses will slow down now, since the easy-to-melt ice in Kara, Laptev etc is mostly gone?  However I was expecting area losses to slow down first, due to the recent switch to cyclonic weather, but that slowdown hasn't happened yet...

[be cause]

gero's forecast continues to fall .. was 4.5 m 16 days ago , now it's 4.05 m . I'd say it's tumbling toward my forecast .

[HapHazard]

So how's everyone feeling about their predictions here now?

I, as always  , will end up smack in the middle of my bin. (3.75 and 4.25)

[Bruce Steele]

Looks like 50% of us will be in a winning bin , with twenty five % over and twenty five %  under.
Not many votes in the pool but many good guesses .

[Bruce Steele]

Looks like I was low again this year, ignore post above.