Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Juan C. García on July 01, 2020, 12:01:46 AM

Title: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: Juan C. García on July 01, 2020, 12:01:46 AM
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:

 Year               Extent
                  10^6 km2
1980's Avg.     7.19
1990's Avg.     6.49
2000's Avg.     5.41
2010's Avg.     4.33
2000               6.04
2001               6.55
2002               5.51
2003               5.93
2004               5.68
2005               5.18
2006               5.63
2007               4.07
2008               4.50
2009               5.05
2010               4.62
2011               4.27
2012               3.18
2013               4.81
2014               4.88
2015               4.26
2016               4.02
2017               4.47
2018               4.46
2019               3.96

The 2020 minimum is  3,554,798 km2, reached on September 13th.
The right bins are 3.50 - 4.00M and 3.25-3.75M km2.


Order by lowest to highest:
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: JNap on July 01, 2020, 02:50:15 AM
From another poll earlier this year, I also voted from 3.5 - 4.0 range with a specific prediction of 3.8M.   

I still voted for 3.5 - 4.0 range this time,  but I think that the emerging High pressure system will extend for many days during the peak insolation season and will ultimately impact the extent.  Thus my specific prediction has lowered a little to between 3.6 - 3.7M  -- a clear second place finish in the satellite era.

Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: Juan C. García on July 01, 2020, 07:21:09 AM
June poll for JAXA: 3.50-4.00M km2 MC (Medium confidence)
June poll for NSIDC: 4.00-4.50M km2 MC (Medium confidence)
June poll for PIOMAS: 4.00-4.50K km3 MC (Medium confidence)
I will keep my June forecast:
JAXA: 3.50-4.00M km2
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: oren on July 01, 2020, 02:27:00 PM
I am also keeping 3.50-4.00, but I think the probability of it happening has grown significantly. Higher chance of downside than upside surprise IMHO. However to break 2012's record also requires perfect compaction around the minimum, which I think greatly lowers the probability. I wouldn't be surprised by a new area record though.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: Stephan on July 01, 2020, 10:34:33 PM
Same bin chosen than in June: 4.00 ± 0.25 M km²
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: Michael Hauber on July 02, 2020, 02:36:02 AM
3 to3.5.

Comfortably positioned for second place, with a rapid change to cloudy required almost immediately to avoid IMO.  Laptev and Siberian sectors going through an unprecedented mid summer melt.  Question marks over the central basin which is certainly showing less dispersion than 2012, but more than last year, and may have started the season thicker as well.  I'd expect a clear lead in melt in the next week, and then its just a question of whether this year can stay ahead of 2012's surge in August, depending on the state of the central pack and weather conditions for the rest of the season.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: jens on July 02, 2020, 09:44:32 AM
So finally after a long time of waiting 2020 has taken the lead in extent on July 1. Top 8 years are still within 200k though, so it's a tight group in which positions change daily. So let's see if 2020 can pull away somewhat or not.

Anyway, went for the 3.5-4.0 bracket. Even if 2020 narrowly beats all other years bar 2012, that would be enough to get in here.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: slow wing on July 08, 2020, 08:21:48 AM
Also voted [3.5,4.0]M km^2.

Current extent of 8.0M km^2 is a record for the date by 0.3M km^2.

I actually predict this year will pull away further in the next few days, maybe to 0.5M km^2. The reason is the continuing strong high pressure system sitting squarely over the Arctic basin and which is compacting the ice pack due to the coriolis effect ("Ekman pumping").

Afaik the current extent values still don't correlate that strongly with the September minimum though. My low prediction -- second place behind 2012 -- is instead based more on the heat & low ice thickness on the Russian side -- that side is getting wiped out the earliest on record -- & also on the healthy dose of direct sunlight the Arctic is getting at the moment.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: pauldry600 on July 08, 2020, 08:24:53 AM
Still going with 3.9m
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: Juan C. García on July 09, 2020, 02:15:11 AM
Two days left to make your vote or change your vote!
And write us about your forecast!  ;)
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: Wherestheice on July 09, 2020, 03:00:59 AM
I'll error on the side of worst case, and changed to 3-3.50 km2.

With recent extreme losses, I see 2020 competing with 2012, even if things slow down a bit later in the melt season.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: jens on July 09, 2020, 05:15:48 AM
Early July has certainly been delivering. The likelihood of a result in the "lower" range relatively speaking has increased and also the possibility of threatening 2012. It remains to be seen, how much easy-to-melt ice there is still left and how it will unfold.

What I find interesting is that 2019 had a very strong July and now 2020 has started out July even stronger. So perhaps what concerns the month of July a new tipping point has been passed. A bit like a "June tipping point" was passed by 2010, then followed by 2011 and 2012 - all going strongly in that month.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: bluice on July 09, 2020, 10:31:44 AM
Keeping it 3-3.5.

I still expect 2020 to reach the 2nd place but if pro-melt weather continues #1 spot is not out of reach. 

Arctic does have a habit to surprise just like it did in late July last year.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: gerontocrat on July 09, 2020, 11:46:47 AM
Last month I said 3.75-4.25, because I was not brave enough to go with anecdotal evidence form the Mosaic project and others on the rotten state of the winter ice (thin, little structural integrity) + Polar Amplification of AGW + forecasts from Russia of a long, hot Siberian summer for the Arctic shore.

Now I am now not brave enough to go beyond the projection in my spreadsheet from remaining average melt of the last 10 years of 3.77 million km2 (from July 7 data).

So 3.5 to 4.00 for me, although 3.25 to 3.75 is tempting. And low confidence as my predictions have about the same success rate as The Farmer's Almanac & Mystic Meg's Horoscopes for the year.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: PragmaticAntithesis on July 09, 2020, 12:00:37 PM
I'm going with 3.5-4sqMm. I would be genuinely surprised if it went below 3.5, but it looks like above 4 is now wishful thinking.

Also, I'm noticing the poll results are bimodal, with peaks at 3.75-4.25 and 3-3.5. It looks like the forum may be falling into 2 camps, with one expecting an on trend melt season, and the other expecting a 2012 style ice beatdown!
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: Killian on July 09, 2020, 12:25:11 PM
My difficulty with this poll is my prediction (scenarios, preferably) is based on a little data point that comes up in July but not before the end date of the poll!

I went with 3 - 3.5 as a worst-case scenario based on current conditions. I won't be able to change my poll vote, but will update in comments sometime before 7/15 .

Scenario 1: Ice keeps flowing out Fram, melt conditions remain close to ideal, a significant dipole develops, maybe a nice big cyclone. 2.9 ~ 3.25m.

Scenario 2. Ice keeps flowing out Fram, melt conditions remain close to ideal. 3.25m - 3.5

Scenario 3: Poor ice retention conditions ease up in a week or two and we get the same post-2012  pattern of good to very good conditions for ice retention the rest of the summer. 3.5 ~ 3.9.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: SteveMDFP on July 09, 2020, 04:29:03 PM
I'm on the pessimistic side here:  between 2.75 and 3.25

This exceptional insolation period has effects beyond the immediate melting.  Heat is going into the water below the ice and between floes as well. This retained heat will foster more melt even if weather tuns more normal/boring.   I think that melt now also increases the likelihood of cyclones later in the season.  We won't need a GAC to meet or exceed 2012, smaller ones will likely do.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: Comradez on July 11, 2020, 05:07:31 PM
How much extent would this circled section be?
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: KenB on July 11, 2020, 07:02:17 PM
How much extent would this circled section be?

If I've done the math right, I think the area inside your boundary is around 2M km^2.  That's not extent, because it doesn't factor in concentration, but it's an upper bound.  Here's how I reasoned:

The area of the entire cap north of 80N is 3.857M km^2 based on a figure of 6357 km for Earth's radius and a solid angle subtending 20 degrees (here's where I hope I have the math right). 

Your bounded area looks to be just over 1/2 of that, by eye, since it fills 1/4 almost completely, another 1/4 partially, and the rest of your area looks about right to fill the rest of that 1/4 with a bit left over.  Half of the cap is 1.928 M km^2 if the above number is right.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: pleun on July 11, 2020, 07:35:17 PM
On worldview, to the right of the screen there's a measuring tool where you can create a freeform by selecting random points on the screen and it directly gives you the area.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: KenB on July 11, 2020, 07:42:57 PM
lol - should have guessed there was something like that - thanks!  At least I was able to check my math - it looks right.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: oren on July 11, 2020, 09:46:13 PM
Thanks pleun, was not aware of that.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: JNap on July 12, 2020, 12:45:38 AM
How much extent would this circled section be?

I think that approximately 2 million km2 is a good estimate.  I used the Worldview tool to do a rough outline of your area.  See below.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: passenger66 on July 12, 2020, 02:11:18 AM
Last year I predicted 2nd lowest extent and lowest ever PIOMAS. August weather proved me wrong. Now I believe in Stephan's graph +/- weather. Given the GAAC maybe 3.75.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: PragmaticAntithesis on July 16, 2020, 04:20:41 PM
I looked at the data and my tables, somewhat stunned. A minimum of 3.5 million km2 with average remaining melt?

<snip>

On average 65.2% of melting from maximum to minimum done, and 61 days to minimum

Projections. (Table JAXA-Arc1)

Average remaining melt (of the last 10 years) would produce a minimum in Sept 2020 of 3.50 million km2, 0.33 million km2 above the 2012 minimum of 3.18 million km2.

For a new record low minimum extent, remaining melt needs to be 9.5% above the average.

I'm going with 3.5-4sqMm. I would be genuinely surprised if it went below 3.5, but it looks like above 4 is now wishful thinking.

I am going to be 'genuinely surprised', aren't I?
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: Juan C. García on July 16, 2020, 04:56:21 PM
I looked at the data and my tables, somewhat stunned. A minimum of 3.5 million km2 with average remaining melt?

<snip>

On average 65.2% of melting from maximum to minimum done, and 61 days to minimum

Projections. (Table JAXA-Arc1)

Average remaining melt (of the last 10 years) would produce a minimum in Sept 2020 of 3.50 million km2, 0.33 million km2 above the 2012 minimum of 3.18 million km2.

For a new record low minimum extent, remaining melt needs to be 9.5% above the average.

I'm going with 3.5-4sqMm. I would be genuinely surprised if it went below 3.5, but it looks like above 4 is now wishful thinking.

I am going to be 'genuinely surprised', aren't I?
I also voted on the 3.5-4.0 x 10^6 km2.
And I am also going to be 'genuinely surprised' if it goes below 3.5.
But if this trend continues until the end of July, surely above 3.75 will be wishful thinking.
I am starting to think that 3.25-3.75 x 10^6 km2 is the right place to be and it could go lower than that.  :o
Let's wait to see what happens to Beaufort in the next 3 weeks.

Edit:
By "if this trend continues until the end of July" I mean that Gerontocrat forecast is 3.5 x 10^6 km2 right now. I wonder if it will be the same on July 31st.
Projections. (Table JAXA-Arc1)

Average remaining melt (of the last 10 years) would produce a minimum in Sept 2020 of 3.50 million km2,
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: jens on July 16, 2020, 08:45:53 PM
Oh well... Things are happening. I think I would revise my prediction now too.

I'm now torn between 3.25-3.75 and 3.0-3.5. I don't know, but may just as well go all out and go for 3.0-3.5.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: glennbuck on July 21, 2020, 05:18:39 PM
It would not Surprise me if Gerontocrat's Jaxa Arctic sea ice extent chart had a minimum for the 1st of August.

 1.81 million km^2 to 1.99 million km^2

From the 2012 Max (last 10 years)



Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: oren on July 21, 2020, 05:40:10 PM
Welcome, glennbuck.
Title: Re: JAXA 2020 Arctic SIE September daily minimum: July Poll
Post by: Killian on September 17, 2020, 11:21:58 AM
Scenario 3: Poor ice retention conditions ease up in a week or two and we get the same post-2012  pattern of good to very good conditions for ice retention the rest of the summer. 3.5 ~ 3.9.

And so it was.