Author Topic: NSIDC 2018 Arctic SIE September average: August Poll (Read 7012 times)

DavidR · « **on:** July 29, 2018, 08:24:58 AM »

ATTENTION: There are two polls on the ASIF. This one is for NSIDC sea ice extent September average (which is also used for the SIPN sea ice outlook), the other is for JAXA sea ice extent daily minimum (provided by ADS, previously by IJIS). Make sure you are aware of the difference before voting.

These are the September averages for the last 13 years (in millions km2,):

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: 4.51
2017: 4.80

75 voters voted in the July poll with an average prediction of 4.387 M km^2. This is 300K above the JAXA daily minimum in line with the average differences between the two figures since 2005

I have attached a graph showing the difference between the daily minimum and September average for the past thirty years. It should be noted that NSIDC does not necessarily use a standard 'average' of daily values when calculating their reported average.

Paddy · « **Reply #1 on:** July 29, 2018, 10:45:32 AM »

Going for "4.5 to 5.0" for now, but definitely planning to review it in 12 days or so.

Stephan · « **Reply #2 on:** July 29, 2018, 11:07:10 AM »

Have chosen the bin 4.5 to 5.0 mio as in previous polls.

icefisher · « **Reply #3 on:** July 30, 2018, 01:18:04 AM »

4.64 +/- .15. A major typhoon entering from the Pacific side could lower my expectations but the odds on that happening are less than 10%. We need many, many buoys measuring volume.

jdallen · « **Reply #4 on:** July 30, 2018, 01:22:51 AM »

Based on what we're seeing play out on the Pacific side I've dropped a bucket from 4.25-4.75 down to 4.0-4.5

I wouldn't be surprised if I end up coming in high.

EgalSust · « **Reply #5 on:** August 01, 2018, 02:54:32 PM »

Going for 4.75-5.25, same as July, for now. Might change later.

RikW · « **Reply #6 on:** August 01, 2018, 03:09:36 PM »

I'm going for a top-3 finish, thus 4.0-4.5

But I think throwing a dice with options has a better chance at giving a good prediction than any argumentation, this season is feeling weirder every week...

magnamentis · « **Reply #7 on:** August 01, 2018, 07:08:52 PM »

Quote from: RikW on August 01, 2018, 03:09:36 PM

I'm going for a top-3 finish, thus 4.0-4.5

But I think throwing a dice with options has a better chance at giving a good prediction than any argumentation, this season is feeling weirder every week...

we can do both, we can try to reason and throw all the various known facts and believes into the pot to get a best possible picture as long as we don't claim to have borrowed the only truth, means as long as we know that we don't KNOW

discussions based on good motives ( = to learn) are best practice and very interesting as well.

no dogma and no exageration, no buzzwords and no disrespect and all is well

i got the feeling that the many unexpected developments over the last 3 years have improved
the quality of discourse in this forum a lot (looking at myself here as well) LOL

Sterks · « **Reply #8 on:** August 02, 2018, 09:03:41 AM »

Keeping it at 4.5 - 5.0 M km2, tho I still see it going both over and below this range.
The Pacific side, all that broken area, could easily go with a strong storm, putting the season in the lowest three. Or a couple of not so strong storms. But high pressure system alone is not gonna make it especially the ESS.
The high compactness suggests that, as much as August can come warm, the melt could soon stall and stay slow until Sep minimum. Unles a storm...

uniquorn · « **Reply #9 on:** August 02, 2018, 02:35:37 PM »

3.75-4.25, warm winds and waves

GoSouthYoungins · « **Reply #10 on:** August 02, 2018, 07:39:02 PM »

3.75ish. Continue of long term trend. The 50% concentration areas will go in the next 3 weeks, and the "solid" edge will slowly but surely retreat everywhere. Very stormy, wavy weather could make it much worse ( maybe sub 3.0) because the solid pack is not actually very solid.

Tetra · « **Reply #11 on:** August 03, 2018, 12:51:12 PM »

4.5-5.0

Wow. Wasn't aware 2016 was so high on this. I think I misread the Nsidc vs jaxa comparison in July. Nsidc should be higher than jaxa.

Same logic as in the jaxa thread.

Third vs fourth place for 2018.

Tom · « **Reply #12 on:** August 03, 2018, 02:11:11 PM »

Changed from 4.5-5.0 to 4.25-4.75

Going purely on projections based on averages I think about 4.6ish, but have changed bin as I think recent weather means the chances of undershooting are higher than overshooting.

Paddy · « **Reply #13 on:** August 05, 2018, 07:27:49 PM »

I don't really see the logic of the >50% of voters here who aren't backing either 4.25 -> 4.75 or 4.5 -> 5.0. This year is currently solidly within the same range as previous years that finished within this general area and nowhere near any year that finished below 4.25 or above 5.0.

Richard Rathbone · « **Reply #14 on:** August 09, 2018, 03:35:46 PM »

I take are now as being a good indicator of what extent in September will be.

Looking at Wipneus area graphs, I reckon the current position looks a bit lower, but not out of range of 2013 and 2014, and a bit higher, but not out of range of 2015 and 2017, and no longer in a position to catch 2012 or 2016.

2013 and 2014 had September extents around the the top end of the 4.75-5.25 bin, and 2015 and 2017 around the bottom end, so I think thats the obvious bin to pick based on looking at the current state of the Home Brew area.

Slater does much the same thing in a rather more rigorous fashion, but has been all over the place during the last month, starting with a much more pessimistic outlook for ice survival than anomaly persistence and with a rather more optimistic one now (5.36 on Sept 28th).

I don't think 5.36 at the end of the month is quite high enough to go to the 5-5.5 bin for the average, but I have changed my initial vote of 4.5-5 that I made when this poll first came out to 4.75-5.25

Juan C. García · « **Reply #15 on:** August 10, 2018, 02:54:56 PM »

4.25-4.75M km² bin.

slow wing · « **Reply #16 on:** August 11, 2018, 01:16:24 AM »

[4.25,4.75]. Just went up 0.25 from my daily minimum prediction, which I explained in more detail.

gerontocrat · « **Reply #17 on:** August 11, 2018, 12:32:55 PM »

4.25 to 4.75 million km2.

Neven · « **Reply #18 on:** August 11, 2018, 01:12:15 PM »

4.5-5, as in June and July.

Richard Rathbone · « **Reply #19 on:** August 22, 2018, 11:46:04 PM »

SIPN August report is out. Median prediction 4.6

https://www.arcus.org/sipn/sea-ice-outlook/2018/august

Klondike Kat · « **Reply #20 on:** September 01, 2018, 05:51:53 PM »

The smart money (4.5-5.0) is looking good at the moment. The ice may need an extra push (more sunny days, Arctic storm, etc.) to fall below 4.75 this year.

Darvince · « **Reply #21 on:** September 03, 2018, 12:03:05 PM »

At this point the only thing that can lower the ice extent much further is warm compaction winds blowing in from Siberia, since CAA has fallen below freezing for the most part, and the Beaufort patch of sea ice is almost gone already.

Feeltheburn · « **Reply #22 on:** September 17, 2018, 06:05:38 AM »

I voted for 4.5-5.0. one person must not have understood the question (0.75-1.25)

crandles · « **Reply #23 on:** September 17, 2018, 05:41:04 PM »

4.9 on Sept 1st falling to 4.553 on Sept 16th and likely to rise to about 5 or maybe a little more by end of month. Seems almost certain average will be closer to 4.75 than 4.5 or 5. Getting more likely for the average to be under 4.75 rather than over it now, I think.

I went for 4.5 to 5 here but between 4 and 4.5 on the daily JAXA number. Probably shouldn't have had that much difference.

DavidR · « **Reply #24 on:** September 20, 2018, 11:46:27 AM »

Quote from: crandles on September 17, 2018, 05:41:04 PM

4.9 on Sept 1st falling to 4.553 on Sept 16th and likely to rise to about 5 or maybe a little more by end of month. Seems almost certain average will be closer to 4.75 than 4.5 or 5. Getting more likely for the average to be under 4.75 rather than over it now, I think.

I went for 4.5 to 5 here but between 4 and 4.5 on the daily JAXA number. Probably shouldn't have had that much difference.

My current Sept average figure is 4.715 so anything under 4.75 seems unlikely with todays' value at 4.63. The decline in September has been so slow it's hard to guess what will happen over the next 12 days. The decline to the minimum since Sept 1 is actually the 6th largest since 1988 which is really surprising to me.

DavidR · « **Reply #25 on:** September 30, 2018, 03:19:49 PM »

With just one day to go Extent seems to be increasing at the end of the month as slowly as it decreased at the start of the month. The average will be below 4.75 M as it needs to jump by around 1M km^2 tomorrow to push the September average above 4,75 M .

40 of the 76 voters got it right.

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What will the NSIDC 2018 Arctic SIE September average be?

Author Topic: NSIDC 2018 Arctic SIE September average: August Poll (Read 7012 times)

magnamentis

Sterks