Arctic Sea Ice : Forum

Cryosphere => Arctic sea ice => Topic started by: Paddy on June 09, 2019, 10:06:22 AM

Title: September predictions challenge 2019
Post by: Paddy on June 09, 2019, 10:06:22 AM
And it's back! Many thanks to Richard Rathbone for setting this up last year. Rules copied over from last year's thread (https://forum.arctic-sea-ice.net/index.php/topic,2327.0.html):

Quote
This is a challenge which accumulates scores across all the monthly polls on September sea ice to come up with an overall rating of how good the predictions made are. In addition to making a prediction, entrants are required to rate their confidence in that prediction. The higher the confidence, the narrower the margin of error you are allowed, but the higher score you get if the September ice ends up where you predicted it (and the bigger penalty you take if you miss).

Currently included polls are: JAXA daily minimum area, NSIDC September average.
Other polls may be added during the course of the season if their structure fits this challenge.

Points are scored as follows:
Very High Confidence: 10 points if you pick the correct bin, -10 points for all other bins.
High Confidence: 6 points for the correct bin, 2 points if one bin out, -2 points if two bins out, -6 points for all other bins
Medium Confidence: 4 points for the correct bin, 2 points if one bin out, 1 point if two bins out, -1 if three bins out, -2 if four bins out, -4 points for all other bins
Low Confidence: 2 points for the correct bin, 1 point if within 3 bins, -1 point if 4-6 bins out, -2 points for all other bins
Very Low Confidence: 1 point if in the correct bin, no score (or penalty) for any other bin.

Note on portmanteau and end of range bins: these are excluded from the challenge, you may either select a bin within the portmanteau range, or extend the range beyond the poll endpoint for your challenge entry. If the September values fall out of the normal range, scores will be assessed by extending the bin structure. e.g. an end result of 5.9 counts as two bins out for a 5-5.5 entry.

To enter, post guess and confidence in this thread before the closing date of the poll. Editing a post to change the prediction before the closing date is allowed, editing for any reason after the closing date for a poll will result in disqualification from the challenge.

List of entries

Paddy

June
JAXA:  3.75 - 4.25, medium
NSIDC: 4.25 - 4.75, medium

Oren

June
JAXA: 3.5 - 4, medium
NSIDC: 4 - 4.5, medium

b_lumencraft

June
JAXA: 3.5 - 4, high
NSIDC: 3.75 - 4.25, high

Stephan

June
JAXA: 3.75 - 4.25, high
NSIDC:  4 - 4.5, high

jdallen

June
JAXA: 3.75 - 4.25, high
NSIDC: 4 - 4.5, high

Neven

June

JAXA: 3.5 to 4.0, medium
NSIDC: 4.0 to 4.5, medium


Juan C. García

June

JAXA: 3.5 to 4.0, médium
NSIDC: 3.75 to 4.25, médium

Richard Rathbone

June

Jaxa: 3.75-4.25, Medium
NSIDC 4.0 - 4.5, Medium

Sterks

June

Jaxa: 3.75-4.25, Medium
NSIDC 4.0 - 4.5, Medium

Aluminium

June

JAXA: 3.5-4.0 high.
NSIDC: 4.0-4.5 medium.

Brigantine

June

JAXA 3.75 - 4.25 medium
NSIDC 4.25 - 4.75 medium

slow wing

June

JAXA: 3.75 to 4.25, medium
NSIDC: 4.00 to 4.50, medium

jplotinus

June

JAXA: 4.25-4.75, low
NSIDC: 4.50-5.00, low

Gerontocrat

June

JAXA: 3.75 to 4.25, High
NSIDC: 4.00 to 4.50, High

Steven

June

JAXA: 3.5 to 4.0, medium
NSIDC: 4.0 to 4.5, medium
Title: Re: September predictions challenge 2019
Post by: oren on June 09, 2019, 11:05:56 AM
Two questions:
A. I take it the bin size is 0.25 million km2?
B. Must the guess here be the same as on the poll thread? I assume not.
Title: Re: September predictions challenge 2019
Post by: Paddy on June 09, 2019, 06:09:21 PM
Two questions:
A. I take it the bin size is 0.25 million km2?
B. Must the guess here be the same as on the poll thread? I assume not.

A. The bin you're guessing at is 0.5m km2 wide, but each step out is measured in 0.25m km2 increments.

So if you guess at 4 to 4.5, and the final extent is 4.9, you count as being 2 bins out. EDIT: If you had gone for Very High Confidence, you would get -10 points. If High, -2 points. If Medium or Low, 1 point. If Very Low, 0 points.

B. No, it does not have to be the same.

EDIT: My June predictions are as follows:
JAXA: 3.75 to 4.25, medium
NSIDC: 4.25 to 4.75, medium
Title: Re: September predictions challenge 2019
Post by: oren on June 09, 2019, 07:00:27 PM
My June prediction: JAXA 3.5-4, medium confidence.
Title: Re: September predictions challenge 2019
Post by: b_lumenkraft on June 09, 2019, 07:23:19 PM
My June prediction:

JAXA  : 3.50 - 4.00, high confidence
NSIDC : 3.75 - 4.25, high confidence
Title: Re: September predictions challenge 2019
Post by: Stephan on June 09, 2019, 07:32:02 PM
My prediction (JAXA Sep minimum): 3.75-4,25 M km², high confidence
My prediction (NSIDC Sep Average): 4.00-4.50 M km², high confidence
Title: Re: September predictions challenge 2019
Post by: jdallen on June 10, 2019, 10:42:22 AM
My prediction (JAXA Sep minimum): 3.75-4,25 M km², high confidence
My prediction (NSIDC Sep Average): 4.00-4.50 M km², high confidence
Ditto.
Title: Re: September predictions challenge 2019
Post by: Neven on June 10, 2019, 02:43:46 PM
My June predictions are as follows:
JAXA: 3.5 to 4.0, medium
NSIDC: 4.0 to 4.5, medium
Title: Re: September predictions challenge 2019
Post by: oren on June 10, 2019, 03:20:33 PM
I will copy Neven's take on NSIDC, 4-4.5 medium.
Title: Re: September predictions challenge 2019
Post by: Juan C. García on June 10, 2019, 03:32:47 PM
My June predictions:

JAXA: 3.5 to 4.0, médium confidence
NSIDC: 3.75 to 4.25, médium confidence
Title: Re: September predictions challenge 2019
Post by: Richard Rathbone on June 10, 2019, 06:54:38 PM
Jaxa: 3.75-4.25, Medium
NSIDC 4.0 - 4.5, Medium

I was intending to run this again, but got distracted by a friend's death just before the polls went up (I have reached the age where such things can be expected to happen). Thanks for setting it rolling Paddy.

The one change I was intending to make was to ask for entries in subsequent months to quote entries from the previous month(s) but that's not relevant this month anyway.
Title: Re: September predictions challenge 2019
Post by: b_lumenkraft on June 10, 2019, 06:57:02 PM
Sorry for your loss Richard.
Title: Re: September predictions challenge 2019
Post by: Sterks on June 10, 2019, 07:03:39 PM
Jaxa: 3.75-4.25, Medium
NSIDC 4.0 - 4.5, Medium
Same, but thinking will be probably around the lower end. Feels like this year can beat 2016 (2nd or 3rd) easily if picks some more melting momentum before solstice
Title: Re: September predictions challenge 2019
Post by: Steven on June 10, 2019, 08:17:35 PM
To enter, post guess and confidence in this thread before the closing date of the poll.

When is the deadline for June predictions in this thread?  Last year the deadline was 16 June, 23:59 UTC, is it the same this year?
Title: Re: September predictions challenge 2019
Post by: Paddy on June 10, 2019, 10:24:03 PM
Sure, why not.
Title: Re: September predictions challenge 2019
Post by: Aluminium on June 11, 2019, 01:45:32 PM
JAXA: 3.5-4.0 high.
NSIDC: 4.0-4.5 medium.
Title: Re: September predictions challenge 2019
Post by: Brigantine on June 12, 2019, 12:19:13 AM
June 2019

JAXA: 4.00 - 4.50 medium (https://forum.arctic-sea-ice.net/index.php/topic,2718.msg203717.html#msg203717) confidence
NSIDC: 4.25 - 4.75 medium (https://forum.arctic-sea-ice.net/index.php/topic,2719.msg203718.html#msg203718) confidence
Title: Re: September predictions challenge 2019
Post by: Brigantine on June 12, 2019, 12:30:08 AM
To enter, post guess and confidence in this thread before the closing date of the poll.

When is the deadline for June predictions in this thread?  Last year the deadline was 16 June, 23:59 UTC, is it the same this year?
For context, the polls last year closed:
JAXA: 2018-06-15 23h52m49s UTC
NSIDC: 2018-06-12 22h10m19s UTC

So basically the deadline for predictions was 24 hours after the later of the polls closed.

This year:
JAXA: 2019-06-11 18h24m20s UTC
NSIDC: 2019-06-11 19h45m19s UTC

I only posted in this thread some hours after the polls closed, but linked to predictions (including confidence level) I posted in the poll threads. Those posts were last edited on June 8. Please let my prediction qualify!  :)
Title: Re: September predictions challenge 2019
Post by: slow wing on June 12, 2019, 05:23:46 AM
June (https://forum.arctic-sea-ice.net/index.php/topic,2718.msg204911.html#msg204911)

JAXA: 3.75 to 4.25, medium
NSIDC: 4.00 to 4.50, medium
Title: Re: September predictions challenge 2019
Post by: Paddy on June 15, 2019, 10:05:45 AM
Closing tomorrow, last chance time to submit or change your prediction
Title: Re: September predictions challenge 2019
Post by: jplotinus on June 15, 2019, 12:00:47 PM
I had guessed there might be a June stall in extent decline, something that is now occurring. Therefore a  “high” bin was selected, which is only “high” in context of the new normal, relative to earlier decades of the satellite measurement era:

4.25-4.75 jaxa
4.50-5.00
Oh, sorry about confidence level omission. I say “low” confidence because the current stall may not last much longer and because July and August weather metrics are not foreseeable, other than temps should be above 0°.
Title: Re: September predictions challenge 2019
Post by: Brigantine on June 15, 2019, 12:53:14 PM
4.25-4.75 jaxa
4.50-5.00 nsidc
OK. But what confidence level?

Since there's still time, I'm revising my JAXA prediction:

June:
JAXA 3.75 - 4.25 medium confidence (down from 4.00 - 4.50 medium confidence last week)
NSIDC 4.25 - 4.75 medium confidence (no change)

Things progressed more than expected in the last week! (though not extent data)
Title: Re: September predictions challenge 2019
Post by: Paddy on June 15, 2019, 02:46:23 PM
Casual ruling: if you don't submit a confidence level, I will assume medium.
Title: Re: September predictions challenge 2019
Post by: gerontocrat on June 15, 2019, 03:28:26 PM
Another hostage to fortune..

JAXA Daily minimum 3.75 to 4.25 million km2 - High Confidence
NSIDC September average 4.00 to 4.50 million km2 - High Confidence

I am going for a relatively small difference between the daily and monthly figures. This is because
- it looks like the slope to minimum is usually shallower than the increase afterwards,
- and I read somewhere (I think) that a study said their model trended to later minimum dates in the future.
This would tend to bring a September average closer to the daily minimum (I think).

What if the weather was so weird it pushed the minimum date to the 1st October?
Earliest minimum 7 Sept 2016,
Latest minimum 21 Sep 2018.
Average 13 Sep. 
Title: Re: September predictions challenge 2019
Post by: Steven on June 16, 2019, 02:55:30 PM
JAXA minimum extent:       3.5 to 4.0,  medium confidence
NSIDC September extent: 4.0 to 4.5,  medium confidence

This is based on linear regression, using the NSIDC sea ice area in mid-June as a predictor for the minimum/September extent.
Title: Re: September predictions challenge 2019
Post by: Paddy on June 16, 2019, 04:52:40 PM
To enter, post guess and confidence in this thread before the closing date of the poll.

When is the deadline for June predictions in this thread?  Last year the deadline was 16 June, 23:59 UTC, is it the same this year?
For context, the polls last year closed:
JAXA: 2018-06-15 23h52m49s UTC
NSIDC: 2018-06-12 22h10m19s UTC

So basically the deadline for predictions was 24 hours after the later of the polls closed.

This year:
JAXA: 2019-06-11 18h24m20s UTC
NSIDC: 2019-06-11 19h45m19s UTC

I only posted in this thread some hours after the polls closed, but linked to predictions (including confidence level) I posted in the poll threads. Those posts were last edited on June 8. Please let my prediction qualify!  :)

Based on what's been said before, I'll be closing this poll tonight, at 23:59 UTC. It's a bit later than precedent from last year, but I'm not too fussed.
Title: Re: September predictions challenge 2019
Post by: b_lumenkraft on June 16, 2019, 05:05:09 PM
Last chance!!

Thanks, Paddy for the poll.
Title: Re: September predictions challenge 2019
Post by: Paddy on July 01, 2019, 03:28:22 PM
And we're open for July entries now.  Put your guesses in anytime between now and 23:59 15/7/19 UTC.
Title: Re: September predictions challenge 2019
Post by: jdallen on July 01, 2019, 07:08:31 PM
My only change is to drop JAXA  one bucket to 3.5-4.0
Title: Re: September predictions challenge 2019
Post by: Paddy on July 03, 2019, 12:33:07 PM
June estimates all added to the original post.

Richard, I somehow missed your post before going back through them to update the OP.  I'm also very sorry for your loss.  Also, the suggestion you made that people should state the month's estimate they're giving when making a post is a very good one, and I'd be grateful if everyone did that. 

EDIT: Incidentally, I'm waiting until we're a bit closer to the deadline before making my own guesstimate this month, especially as we don't yet have the PIOMAS data.
Title: Re: September predictions challenge 2019
Post by: Richard Rathbone on July 06, 2019, 07:50:04 AM
Jaxa: 3.75-4.25, Medium
NSIDC 4.0 - 4.5, Medium



Jaxa 3.25-3.75, M
NSIDC 3.5 - 4.0, M

Fairly spectacularly on the volume cliff, decent on the area cliff, but my preferred momentum indicator for June is the Schroeder melt pond anomaly and usually I don't see that till SIPN comes out which is too late. Having dropped 2 bins, and without my top indicator for the time of year, I'm sticking at Medium.
Title: Re: September predictions challenge 2019
Post by: oren on July 06, 2019, 01:46:08 PM
For July:
Dropping JAXA to 3.25-3.75 and increasing conf to High. I think a finish above 4M has become quite improbable, and below 3M extremely difficult.
Also dropping NSIDC to 3.75-4.25, keeping Medium conf.
Title: Re: September predictions challenge 2019
Post by: Brigantine on July 06, 2019, 11:20:19 PM
June:
JAXA 3.75 - 4.25 medium confidence (down from 4.00 - 4.50 medium confidence last week)
NSIDC 4.25 - 4.75 medium confidence (no change)
July: (provisional)
JAXA 3.75 - 4.25 3.50 - 4.00 high confidence
NSIDC 4.25 - 4.75 4.00 - 4.50 high confidence

Need to do some more thinking about downside risks before the deadline... but here's my back of the envelope backup prediction.
Title: Re: September predictions challenge 2019
Post by: Juan C. García on July 07, 2019, 06:27:12 AM
My June predictions:

JAXA: 3.5 to 4.0, médium confidence
NSIDC: 3.75 to 4.25, médium confidence
My July predictions:

JAXA: 3.25 to 3.75, high confidence
NSIDC: 3.75 to 4.25, high confidence
Title: Re: September predictions challenge 2019
Post by: Paddy on July 09, 2019, 10:24:35 AM
My June predictions are as follows:
JAXA: 3.75 to 4.25, medium
NSIDC: 4.25 to 4.75, medium

My July predictions are as follows:
JAXA: 3.75 to 4.25, medium
NSIDC: 4.0 to 4.5, medium

In terms of risk-reward, I'd be tempted to increase my confidence levels to High, but I think there's a small but significant chance that ice levels could end up quite a bit lower than these estimates.
Title: Re: September predictions challenge 2019
Post by: gerontocrat on July 09, 2019, 11:08:55 AM
Dropped both one bin c.f. June. PIOMAS Volume, area and extent data all seem to point that way. So,
JAXA daily extent minimum 3.5 to 4.0                 Confidence - High**
NSIDC extent sep monthly  average 4.0 to 4.5.    Confidence - High**

** I lied
Title: Re: September predictions challenge 2019
Post by: Neven on July 09, 2019, 01:07:16 PM
My June predictions are as follows:
JAXA: 3.5 to 4.0, medium
NSIDC: 4.0 to 4.5, medium

For July, it's the following, dropping two bins:

JAXA: 3.0 to 3.5, medium
NSIDC: 3.5 to 4.0, high
Title: Re: September predictions challenge 2019
Post by: Viggy on July 09, 2019, 01:26:57 PM
I just cannot see this year not being a record anymore.

JAXA - 2.25 - 2.75 (High)
NSIDC - 2.75 - 3.25 (High)
Title: Re: September predictions challenge 2019
Post by: magnamentis on July 09, 2019, 07:50:33 PM
I just cannot see this year not being a record anymore.

JAXA - 2.25 - 2.75 (High)
NSIDC - 2.75 - 3.25 (High)

if 2019 will reach a >300km2 gap in early august it's quite probable because then the GAC has been pre-compensated. if they reach the second week of august head-on, chance are high that 2012 will make the race one last time ;)
Title: Re: September predictions challenge 2019
Post by: Stephan on July 09, 2019, 09:54:14 PM
I stay with my guesses I made around a month ago and I hope extent will not drop further than:
JAXA Sep minimum: 3.75-4.25 M km², high confidence
NSIDC Sep Average: 4.00-4.50 M km², high confidence
Title: Re: September predictions challenge 2019
Post by: Paddy on July 10, 2019, 04:36:40 AM
Droping my JAXA bin a half step further to 3.5 - 4.0.  Still Medium confidence.
Title: Re: September predictions challenge 2019
Post by: charles_oil on July 10, 2019, 04:52:19 AM

Jaxa 3.25 - 3.75    Medium
NSIDC 3.5 - 4     High
Title: Re: September predictions challenge 2019
Post by: Viggy on July 10, 2019, 06:53:44 AM
I just cannot see this year not being a record anymore.

JAXA - 2.25 - 2.75 (High)
NSIDC - 2.75 - 3.25 (High)

if 2019 will reach a >300km2 gap in early august it's quite probable because then the GAC has been pre-compensated. if they reach the second week of august head-on, chance are high that 2012 will make the race one last time ;)

We are already 157k lower than 2012. I dont know if a 300k head start is enough since 2012 lost over a million km2 at the start of August. But, I am also expecting 2019 to be potentially over 500k lower than 2012 in early August.
Title: Re: September predictions challenge 2019
Post by: Aluminium on July 11, 2019, 11:35:42 AM
JAXA: 3.5-4.0 high.
NSIDC: 4.0-4.5 medium.
JAXA: 3.5-4.0 high.
NSIDC: 3.75-4.25 high.
Title: Re: September predictions challenge 2019
Post by: slow wing on July 11, 2019, 12:05:20 PM
Missed the cutoff time again, sorry.

June

JAXA: 3.75 to 4.25, medium
NSIDC: 4.00 to 4.50, medium

July

JAXA: 3.25 to 3.75, medium
NSIDC: 3.50 to 4.00, medium
Title: Re: September predictions challenge 2019
Post by: Steven on July 14, 2019, 02:35:13 PM
JAXA minimum extent:       3.5 to 4.0,  medium confidence
NSIDC September extent: 4.0 to 4.5,  medium confidence

This is based on linear regression, using the NSIDC sea ice area in mid-June as a predictor for the minimum/September extent.

July:

JAXA:     3.25 to 3.75,  medium
NSIDC:  3.75 to 4.25,  medium

This is based on linear regression, as before.  I was tempted to choose high confidence rather than medium, but I'm not willing to take the risk.
Title: Re: September predictions challenge 2019
Post by: Steven on July 14, 2019, 02:37:22 PM
Missed the cutoff time again

Not really.  The deadline for July predictions in this thread is tomorrow, 15 July at 23:59 UTC, as announced by Paddy upthread.
Title: Re: September predictions challenge 2019
Post by: Richard Rathbone on July 16, 2019, 08:32:38 PM
If SIPN entries had been made here: (these are a late commentary on selected June entries, not July, which is scheduled for release next week)

CPOM (Schroeder, based on May melt pond statistics) mean 4.3 sd 0.5 which is probably 4-4.5 M, but not far short of H.

UK met office (dynamic model, seasonal forecaster using ensembles from May conditions) mean 5.2 sd 0.3 which is 5-5.5 H.

US Navy (dynamic model, often referred to on these boards as HYCOM) 5.2-6.3 ensemble range, which is 5.5-6.0 M (would be H but they say the ensemble range is an under estimate in their submission)

NISDC expert group guesstimates mean 4.4 sd 0.33, which is 4.25-4.75 M (rather than H on the basis that the sd is just the variation between experts, not how confident the experts are)

NSIDC Boulder (statistics with a Slater like approach but not the actual Slater model) Mean 5.59, 95% range 3.66-7.97,  which is 5.25-5.75 L (maybe even VL)

Nico Sun a.k.a. Tealight, (statistics on albedo calculations) median 4.4 range 3.73-4.88, which is 4-4.5 H.

University of Washington (dynamic model, PIOMAS forced by a seasonal weather forecast) 4.07 +- 0.40, which is 3.75-4.25 H (might really be M but they aren't clear what the 0.4 actually is and I'm treating it as total uncertainty rather than a single standard deviation)

I expect there to be an update using June melt pond data from Schroeder but a lot of the others just make the one SIPN entry, though it would be interesting to see how an extra month of data changed the models.
Title: Re: September predictions challenge 2019
Post by: Richard Rathbone on July 25, 2019, 06:25:56 AM
If SIPN entries had been made here, July edition, hot off the press.

CPOM (Schroeder, based on June melt pond statistics) mean 4.1 sd 0.5 which is probably 3.75-4.25 M, but not far short of H. Only drops 0.2 from June entry, despite record June melt pond fraction.

UK met office (dynamic model, seasonal forecaster using ensembles from June conditions) mean 5.2 sd 0.3 which is 5-5.5 H. Suspiciously similar to the previous entry.

US Navy (dynamic model, often referred to on these boards as HYCOM) 3.1-4.1 ensemble range, which is 3.25-3.75 M (would be H but they say the ensemble range is an under estimate in their submission) Massive drop from their June entry.

NSIDC Slater model 4.46, no uncertainty quantified, so 4.25-4.75 VL.

Nico Sun a.k.a. Tealight, (statistics on albedo calculations) median 3.95 range 3.61-4.17, which is 3.75-4.25 H. Down a notch, range shrunk quite a bit but stays at H because it doesn't fit the contest ranges neatly.

University of Washington (dynamic model, PIOMAS forced by a seasonal weather forecast) 4.26 +- 0.40, which is 4.0-4.5 H (might really be M but they aren't clear what the 0.4 actually is and I'm treating it as total uncertainty rather than a single standard deviation) Up a notch when almost everyone else is dropping.
Title: Re: September predictions challenge 2019
Post by: DrTskoul on July 25, 2019, 06:27:52 AM
We will see how statistical models fare....
Title: Re: September predictions challenge 2019
Post by: Richard Rathbone on August 05, 2019, 08:06:17 PM
Jaxa: 3.75-4.25, Medium
NSIDC 4.0 - 4.5, Medium



Jaxa 3.25-3.75, M
NSIDC 3.5 - 4.0, M


JAXA 3.5-4.0 H
NSIDC 3.75 - 4.25 H

PIOMAS indicates to me that a record is still just about on, Slater looks 4.25 ish though I won't see the Aug 1st prediction for SIPN till after poll deadlines. Last year I was toying with VH at this stage, this year I'm wondering if I should have stuck with M. Just how massive is the momentum from June that carries the melt for the last month before the minimum? Has it dissipated, does it need a GAC to push the ice out over the hot water?
Title: Re: September predictions challenge 2019
Post by: Juan C. García on August 09, 2019, 06:04:57 AM
My June predictions:

JAXA: 3.5 to 4.0, médium confidence
NSIDC: 3.75 to 4.25, médium confidence
My July predictions:

JAXA: 3.25 to 3.75, high confidence
NSIDC: 3.75 to 4.25, high confidence
My August predictions:

JAXA: 3.50 to 4.00, very high confidence
NSIDC: 4.00 to 4.50, very high confidence


P.S. Only ~1.5 days to vote or change your vote...
Am I right? Or we will have more time on this challenge?  ???
Title: Re: September predictions challenge 2019
Post by: Paddy on August 09, 2019, 08:02:06 AM
My June predictions are as follows:
JAXA: 3.75 to 4.25, medium
NSIDC: 4.25 to 4.75, medium

My July predictions are as follows:
JAXA: 3.75 to 4.25, medium
NSIDC: 4.0 to 4.5, medium


Droping my JAXA bin a half step further to 3.5 - 4.0.  Still Medium confidence.

My August predictions are as follows:
JAXA: 3.5 to 4.0, high
NSIDC: 3.75 to 4.25, high

Deadline for entries is the 15th of the month, as per precedent.
Title: Re: September predictions challenge 2019
Post by: Stephan on August 09, 2019, 10:16:33 AM
My prediction (JAXA Sep minimum): 3.75-4,25 M km², high confidence
My prediction (NSIDC Sep Average): 4.00-4.50 M km², high confidence
I repeat this prediction, both values with high confidence.
Title: Re: September predictions challenge 2019
Post by: slow wing on August 10, 2019, 05:37:50 AM
JAXA:     3.50 to 4.00,  medium (minimum day extent)
NSIDC:   4.00 to 4.50,  medium (September average extent)
Title: Re: September predictions challenge 2019
Post by: oren on August 10, 2019, 08:53:58 AM
For July:
Dropping JAXA to 3.25-3.75 and increasing conf to High. I think a finish above 4M has become quite improbable, and below 3M extremely difficult.
Also dropping NSIDC to 3.75-4.25, keeping Medium conf.
Keeping the same for August. My best daily bet is 3.50-4.00 but I still see an option of going below, with very low chances of going above, so I'm skewing my bin accordingly.
Title: Re: September predictions challenge 2019
Post by: Neven on August 10, 2019, 10:37:17 PM
My June predictions are as follows:
JAXA: 3.5 to 4.0, medium
NSIDC: 4.0 to 4.5, medium

For July, it's the following, dropping two bins:

JAXA: 3.0 to 3.5, medium
NSIDC: 3.5 to 4.0, high

And for August, it's:

JAXA: 3.25 to 3.75, high
NSIDC: 3.75 to 4.25, high
Title: Re: September predictions challenge 2019
Post by: Aluminium on August 11, 2019, 08:37:31 PM
JAXA: 3.5-4.0 high.
NSIDC: 4.0-4.5 medium.
JAXA: 3.5-4.0 high.
NSIDC: 3.75-4.25 high.
JAXA: 3.5-4.0 very high.
NSIDC: 3.75-4.25 high.

"Very high" is as attractive as the red button "do not press". :)
Title: Re: September predictions challenge 2019
Post by: Juan C. García on August 12, 2019, 04:39:11 AM
"Very high" is as attractive as the red button "do not press". :)
It is the gambler choice: win all or lose all.  8)
Title: Re: September predictions challenge 2019
Post by: Richard Rathbone on August 12, 2019, 07:39:43 PM
Jaxa: 3.75-4.25, Medium
NSIDC 4.0 - 4.5, Medium



Jaxa 3.25-3.75, M
NSIDC 3.5 - 4.0, M


I'm adjusting my August entry to
NSIDC  4.0-4.5 H
on the basis of Slater 50-day showing probable extent back up to 5 by the end of September. Sticking with
JAXA 3.5 - 4.0 H.
Title: Re: September predictions challenge 2019
Post by: Brigantine on August 14, 2019, 06:25:03 AM
June:
JAXA 3.75 - 4.25 medium confidence
NSIDC 4.25 - 4.75 medium confidence
July:
JAXA 3.50 - 4.00 high confidence
NSIDC 4.00 - 4.50 high confidence
August: (provisional)
JAXA 3.50 - 4.00 high confidence
NSIDC 3.75 - 4.25 high confidence
Title: Re: September predictions challenge 2019
Post by: Steven on August 14, 2019, 09:01:30 PM
JAXA minimum extent:       3.5 to 4.0,  medium confidence
NSIDC September extent: 4.0 to 4.5,  medium confidence

JAXA:     3.25 to 3.75,  medium
NSIDC:  3.75 to 4.25,  medium

August:

JAXA:     3.5  to 4.0,    high
NSIDC:  3.75 to 4.25,  high
Title: Re: September predictions challenge 2019
Post by: AndyW on August 15, 2019, 03:10:44 PM
About 4 million

Not that it matters, the long term trends are what matters.  So I will not be losing any sleep over it.

Title: Re: September predictions challenge 2019
Post by: Paddy on August 16, 2019, 11:56:17 AM
Now that this is closed, I could potentially calculate the scores resulting from each ultimate outcome... but I think that sounds like a bit too much work. If anyone else wants to, they should feel free, however.
Title: Re: September predictions challenge 2019
Post by: Juan C. García on August 20, 2019, 11:54:14 PM
Now that this is closed, I could potentially calculate the scores resulting from each ultimate outcome... but I think that sounds like a bit too much work. If anyone else wants to, they should feel free, however.
Let's wait until September when we can be sure of the 2019 minimum and maybe guess the NSIDC Monthly average.
Title: Re: September predictions challenge 2019
Post by: Paddy on August 26, 2019, 12:51:27 PM
Anyone else feeling bemused that their June prediction is looking a lot better than their August one right now?
Title: Re: September predictions challenge 2019
Post by: Klondike Kat on August 26, 2019, 03:11:24 PM
Anyone else feeling bemused that their June prediction is looking a lot better than their August one right now?

I did not make an August prediction, but was feeling that my June prediction of NSIDC of 4.0-4.5 was looking rather bleak in early August.  Now, it is looking better as a sub 4.0 extent is appearing less likely.
Title: Re: September predictions challenge 2019
Post by: Brigantine on August 29, 2019, 02:15:57 AM
Anyone else feeling bemused that their June prediction is looking a lot better than their August one right now?
I'm feeling you there! But if my August one is out by 1 bin, I'll still be happy.
Happy I didn't pick very high confidence ;)

JAXA under 4.00 is still touch and go, but NSIDC under 4.25 is starting to look distant.

Looking at each of our predictions, it seems we think very alike!

Hypothetical scoring:
Only included contestants scoring over 20 or in the top 3 in the particular or adjacent bin.
I wanted to put this in a spoiler box, but that didn't work so I did this.

JAXA 4.30, NSIDC 4.76: jplotinus 4, Slow Wing 2, Stephan 0, Paddy -2
JAXA 4.26, NSIDC 4.60: Stephan 12, Paddy 5, SW 5, gerontocrat 4, jdallen 4, jplotinus 4, Brigantine 2
JAXA 4.10, NSIDC 4.51: Stephan 24, gc 12, jda 12, Paddy 12, Brig 12, SW 10
JAXA 4.10, NSIDC 4.40: Stephan 36, gc 20, jda 20, Brig 20, Paddy 18, Richard Rathbone 18, SW 16, Steven 13, Aluminium 2, Juan C. Garcia 0
JAXA 3.99, NSIDC 4.40: Stephan 36, Aluminium 30, JCG 30, Brig 28, Paddy 24, gc 24, jda 24, RR 23, Steven 20, SW 19, oren 16
JAXA 3.90, NSIDC 4.24: Al 38, JCG 36, Stephan 36, Brig 30, Paddy 26, Steven 26, gc 24, jda 24, RR 24, oren 20, SW 20, Neven 19
JAXA 3.74, NSIDC 4.10: JCG 40, Al 38, oren 28, Steven 28, Brig 28, Paddy 24, RR 24, Neven 24, Stephan 24, gc 20, jda 20, SW 20
JAXA 3.70, NSIDC 3.99: Al 36, Neven 26, oren 26, Steven 26, Brig 23, Paddy 21, JCG 20, RR 20, SW 18, gc 12, jda 12, Stephan 12
Title: Re: September predictions challenge 2019
Post by: Richard Rathbone on September 02, 2019, 05:27:50 PM
August SIPN report is out.

https://www.arcus.org/sipn/sea-ice-outlook/2019/august

Of the ones I tend to track most:
CPOM (Schroeder, melt pond statistics) 4.1
NSIDC (Slater/Barrett, concentration statistics) 4.16
APL (PIOMAS forced by long range weather forecast) 4.4
Navy (HYCOM/CICE model) 3
Nico Sun (Tealight, albedo statistics) 4.13

4-4.5 still looks a good bet to me. I don't hold out much hope for the Navy being within the 2.7-3.2 range they give.
Title: Re: September predictions challenge 2019
Post by: Juan C. García on September 17, 2019, 05:56:08 AM
2019 JAXA min, as of September 16th --> 3.99M km2.
      Correct bins: 3.75-4.25   &   3.50-4.00

2019 NSIDC September average, until now (Sept 1st-15th) --> 4.29M km2. *
     Correct bin:  4.00-4.50
     Possible correct bins: 4.25-4.75   or   3.75-4.25  (depending on values on the rest of Sept.)

* For the average, using daily values (no 5-day trailing average).
The last value is Sept 15th: 4.16M km2 (so the average will decrease on the following days, but certainly the average will increase at the end of the month).
Title: Re: September predictions challenge 2019
Post by: Neven on September 17, 2019, 09:49:41 AM
My June predictions are as follows:
JAXA: 3.5 to 4.0, medium
NSIDC: 4.0 to 4.5, medium

For July, it's the following, dropping two bins:

JAXA: 3.0 to 3.5, medium
NSIDC: 3.5 to 4.0, high

And for August, it's:

JAXA: 3.25 to 3.75, high
NSIDC: 3.75 to 4.25, high

Looks like my June predictions will be correct. Which are the hardest, of course.  ;)
Title: Re: September predictions challenge 2019
Post by: Paddy on September 17, 2019, 12:23:20 PM
My June predictions are as follows:
JAXA: 3.75 to 4.25, medium
NSIDC: 4.25 to 4.75, medium

My July predictions are as follows:
JAXA: 3.75 to 4.25, medium
NSIDC: 4.0 to 4.5, medium


Droping my JAXA bin a half step further to 3.5 - 4.0.  Still Medium confidence.

My August predictions are as follows:
JAXA: 3.5 to 4.0, high
NSIDC: 3.75 to 4.25, high

Deadline for entries is the 15th of the month, as per precedent.

My JAXA predictions have been lucky enough to be fine throughout, but not so much NSIDC... either I guessed too high in June or too low in August. So probably either 26 or 24 points for me, depending.
Title: Re: September predictions challenge 2019
Post by: Juan C. García on September 17, 2019, 12:34:12 PM
My June predictions:

JAXA: 3.5 to 4.0, médium confidence
NSIDC: 3.75 to 4.25, médium confidence
My July predictions:

JAXA: 3.25 to 3.75, high confidence
NSIDC: 3.75 to 4.25, high confidence
My August predictions:

JAXA: 3.50 to 4.00, very high confidence
NSIDC: 4.00 to 4.50, very high confidence
"Very high" is as attractive as the red button "do not press". :)
It is the gambler choice: win all or lose all.  8)
I made a gambling guess in August and I was close to losing it, but with the 3.99M km2, I am on the winner side again. 20 points just for the August bins.  :) I will have to wait for the other NSIDC bins.

P.S. NSIDC average can still go above 4.50M km2, but I strongly doubt it. Maybe it can go under 4.25M km2. A little more chance, even that I also doubt it.
Title: Re: September predictions challenge 2019
Post by: Richard Rathbone on September 18, 2019, 03:57:10 PM


Looks like my June predictions will be correct. Which are the hardest, of course.  ;)

I reckon June is the easiest. Its much harder quantifying how much skill I have in later months, but no skill is easy to quantify.

Anyone feeling nervous about JAXA dropping below 3.75 yet?
Title: Re: September predictions challenge 2019
Post by: oren on September 18, 2019, 05:37:50 PM
I'm willing to bet it's not gonna happen. But the Arctic can always surprise.
Title: Re: September predictions challenge 2019
Post by: Stephan on September 21, 2019, 08:25:49 AM
My prediction (JAXA Sep minimum): 3.75-4,25 M km², high confidence
My prediction (NSIDC Sep Average): 4.00-4.50 M km², high confidence
I repeat this prediction, both values with high confidence.
I think I got it right  :)
Title: Re: September predictions challenge 2019
Post by: Stephan on September 21, 2019, 08:27:14 AM

Anyone feeling nervous about JAXA dropping below 3.75 yet?

It will drop below 3.75 M km², but not in 2019  ;)
Title: Re: September predictions challenge 2019
Post by: Paddy on September 30, 2019, 11:48:39 AM
So, now that we can safely call the correct NSIDC bins as being 4.00 - 4.50 & 4.25 - 4.75 M km2, does anyone have the free time and inclination to tot up the final scores?  Apologies for being lazy / distracted by other nonsense...
Title: Re: September predictions challenge 2019
Post by: Juan C. García on October 01, 2019, 10:28:50 PM
Hope that these tables are OK:
Title: Re: September predictions challenge 2019
Post by: Juan C. García on October 02, 2019, 01:32:32 AM
Hope all the calculations are ok.
(Let me know if there is a correction to make ;) )
Title: Re: September predictions challenge 2019
Post by: blumenkraft on October 02, 2019, 06:34:42 AM
Congrats, Stephan!! \o/
Title: Re: September predictions challenge 2019
Post by: Stephan on October 02, 2019, 08:25:43 AM
wow, I hadn't expected it to be correct with my estimations right from the start...
Thanks for the congratulations, blumenkraft

"Auch ein blindes Huhn findet einmal ein Korn"
Title: Re: September predictions challenge 2019
Post by: blumenkraft on October 02, 2019, 08:27:10 AM
Hihi :D
Title: Re: September predictions challenge 2019
Post by: Richard Rathbone on October 02, 2019, 12:09:53 PM
"If SIPN entries had been here" results:

CPOM (Schroeder, based on melt pond statistics) 4,2,2 = 8

UK met office (dynamic model, seasonal forecaster) -6,-6,none = -12

US Navy (dynamic model, often referred to on these boards as HYCOM) -4,-1,-4 = -9

NSIDC Slater model (concentration statistics) no entry,1,1 = 2 (spot on but no error margin given)

Nico Sun a.k.a. Tealight, (statistics on albedo calculations) 6,2,6 = 14

University of Washington (dynamic model, PIOMAS forced by a seasonal weather forecast) 2,6,6 = 14

Note how PIOMAS crushes the other dynamic models, not only because it was more accurate, but also because the other models have a very poor appreciation of just how inaccurate they are.

CPOM and Tealight are a lot closer than those numbers suggest, one being just the right side and the other just the wrong side of being put in higher value bins.

Statistical models did well, but it was a year that finished close to trend, and it needs a year with markedly good or bad melt to sort them out from one another.
Title: Re: September predictions challenge 2019
Post by: jdallen on October 05, 2019, 01:49:11 AM
Hope all the calculations are ok.
(Let me know if there is a correction to make ;) )
How did I miss the August polls?

Well, even without them, I did better 'n Average ;)
Title: Re: September predictions challenge 2019
Post by: Juan C. García on October 05, 2019, 04:19:34 AM
My prediction (JAXA Sep minimum): 3.75-4,25 M km², high confidence
My prediction (NSIDC Sep Average): 4.00-4.50 M km², high confidence
Ditto.

You were following Stephan vote, so if you didn't missed the August poll, you would be in first place, like him...
Title: Re: September predictions challenge 2019
Post by: jdallen on October 05, 2019, 08:59:00 AM
*That* must be what happened.  I'll take the honorary victory.
Title: Re: September predictions challenge 2019
Post by: Aluminium on October 05, 2019, 07:06:20 PM
I made my forecast by calculations for JAXA and by intuition for NSIDC. The difference is obvious.
Title: Re: September predictions challenge 2019
Post by: Juan C. García on October 06, 2019, 02:18:21 AM
I was wishing that 2019 could break the 2007 NSIDC September average. That explains my June and July votes (3.75-4.25M km2, definitely below the 2007 record of 4.27M km2). But 2007 had a very late refreeze, so it is difficult to break the average, even that 2019 had a lower NSIDC daily mínimum than 2007. Of course, the very low melt/compactation at the end of August 2019 had also an influence. A little more melt/compactation in August and 2019 would break the NSIDC 2007 September average.

Anyway, second place tied with Aluminium, it is good enough.  ;)