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What will the CT 2013 Arctic SIA daily minimum be?

More than 3.5 million km2
0 (0%)
Between 3.25 and 3.5 million km2
1 (1.3%)
Between 3.0 and 3.25 million km2
1 (1.3%)
Between 2.75 and 3.0 million km2
1 (1.3%)
Between 2.5 and 2.75 million km2
2 (2.6%)
Between 2.25 and 2.5 million km2
6 (7.8%)
Between 2.0 and 2.25 million km2
18 (23.4%)
Between 1.75 and 2.0 million km2
24 (31.2%)
Between 1.5 and 1.75 million km2
9 (11.7%)
Between 1.25 and 1.5 million km2
3 (3.9%)
Between 1.0 and 1.25 million km2
2 (2.6%)
Between 0.75 and 1.0 million km2
6 (7.8%)
Between 0.5 and 0.75 million km2
1 (1.3%)
Between 0.25 and 0.5 million km2
2 (2.6%)
Between 0 and 0.25 million km2
1 (1.3%)

Total Members Voted: 75

Voting closed: May 31, 2013, 12:16:33 PM

Author Topic: Cryosphere Today 2013 Arctic SIA daily minimum: May poll  (Read 36940 times)

Chuck Yokota

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #50 on: May 19, 2013, 01:01:03 PM »
ChrisReynolds and Crandles,

Thanks.  I can see that it is easy to over-interpret a limited amount of information, and see "trends" that don't have statistical significance.
« Last Edit: May 19, 2013, 01:09:50 PM by Chuck Yokota »

slow wing

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #51 on: May 24, 2013, 12:53:59 PM »
Due to the slow start to the melting, I went up one bin from my prediction last month. This month I went for "Between 1.75 and 2.0 million km^2".

I have to admit that I waited until late in the month in order to be able to take account of the melt progress during the month. Waiting until late in the month will make an even bigger difference next month, when the melt will be in full swing, but I will feel a bit like I am cheating by waiting to see the melt progress during the month.

Neven, I realise that you are too busy to do a new poll every two weeks. Maybe you could instead consider restricting the voting to the first two weeks after the poll opens in order that everyone is predicting based on a similar state of knowledge?

Neven

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #52 on: May 24, 2013, 02:27:12 PM »
That might be a good idea, slow wing. I'll keep it in mind for next month's poll.
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Andre Koelewijn

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #53 on: May 29, 2013, 05:01:26 PM »
Voted between 1.25M and 1.5M km2, again.

As I wrote on April 7th in the previous poll:
Based on an eye-balled guess from the figures since, roughly, 2005.
Yet, I hope it will turn out to be higher, which would then be a result of good weather (i.e. bad for melting).
I believe the amount of ice mid-September is determined by both area and volume, and the downward trend of PIOMAS doesn't promise a rebound - and note that the declining PIOMAS-average has been clearly too high in the past years.


Although the melt slowed down a bit recently, I'm afraid it will soon pick up again. Much will depend on the weather from Mid-July till end of August, but where last year showed a vast amount of rather thin ice around the pole (see Apocalypse4real's site), this year North (!) of the 'HYCOM black ice' North of the CAA and beyond more melt is likely to take place, especially when storms mix all up along the edges.

Neven

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #54 on: May 30, 2013, 09:16:41 PM »
Two century breaks in a row, but still highest since 2005:

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Neven

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #55 on: May 31, 2013, 12:35:09 AM »
Comparing day-to-day changes on the UB SIC maps and given the current forecasts, I think we'll see more big drops in days to come.
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sofouuk

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #56 on: May 31, 2013, 04:48:51 AM »
everything seems set up for an early june crash - if that doesn't happen there'll be some headscratching  ::)

crandles

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #57 on: May 31, 2013, 11:37:11 PM »
I am a bit late, but as per the volume predictions thread (Chris Reynolds reply #152 here), I would choose 2 to 2.25.

(Thanks Chris for finishing that off for me.)

ChrisReynolds

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #58 on: May 31, 2013, 11:45:53 PM »
everything seems set up for an early june crash - if that doesn't happen there'll be some headscratching  ::)

It will certainly leave me puzzled.

Crandles,

I'm still sticking with a PDF with a peak in 1.75 to 2M km^2, although I'd guess the downside tail is thinner, and the upside thicker.

crandles

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #59 on: May 31, 2013, 11:56:06 PM »
Crandles,

I'm still sticking with a PDF with a peak in 1.75 to 2M km^2, although I'd guess the downside tail is thinner, and the upside thicker.

IOW pretty similar to the votes cast PDF.  ;)  ;D
Seems a pretty sensible PDF.

ChrisReynolds

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #60 on: June 01, 2013, 11:11:03 AM »
Well, my PDF would be down to virtually zero for under 1M.

Jim Pettit

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #61 on: June 02, 2013, 02:30:32 PM »
Now that May's final numbers are in, time for some interesting CT SIA statistics for those of you who care about such things:

--Area dropped by just 1.35 million km2 during May. That's far below the 1979-2012 average May drop of 1.72 million km2, and is in fact the third smallest May area decrease on the record; only 1989 and 1996 saw smaller May decreases.

--The long-term average May decrease has been 589k km2 greater than the average April decrease. This year, just 4k km2 more ice disappeared in May than in April.

--Area increased on eight separate days during May, for a total of 219k km2. By comparison, area increased on only two days in May of 2012, and that for a total of just 14k km2.

--Area now stands at 10.66 million km2. That's the highest June 1 value since 2001. (2008 had the lowest value for the date, 9.87 million km2.)

--Area is now 716k km2 higher than it was on this day last year. If the rest of the melt season were to progress as exactly as it did in 2012, the minimum would wind up around 2.95 million km2.

Neven

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #62 on: June 03, 2013, 11:49:50 PM »
There will be a new poll tomorrow, as soon as a trend line shows up on my CT SIA graph (need two June days for that).
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crandles

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #63 on: June 04, 2013, 01:35:35 AM »
I would suggest not opening the polls (ie dummy poll options like 'does not open' and 'til later') until after PIOMAS updates.

Neven

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #64 on: June 04, 2013, 01:38:52 AM »
Good idea, crandles! I'll wait a couple of days longer.
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crandles

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #65 on: June 04, 2013, 02:41:53 AM »
Time to compare April and May polls:

__________________________________April______May
More than 3.5 million km2__________0 (0.00%)_ 0 (0.00%)
Between 3.25 and 3.5 million km2___0 (0.00%)_ 1 (1.3%)
Between 3.0 and 3.25 million km2___2 (02.1%)_ 1 (1.3%)
Between 2.75 and 3.0 million km2___2 (02.1%)_ 1 (1.3%)
Between 2.5 and 2.75 million km2___5 (05.3%)_ 2 (2.6%)
Between 2.25 and 2.5 million km2__11 (11.6%)_ 6 (7.7%)
Between 2.0 and 2.25 million km2__12 (12.6%)_ 19 (24.4%)
Between 1.75 and 2.0 million km2__28 (29.5%)_ 24 (30.8%)
Between 1.5 and 1.75 million km2__13 (13.7%)_ 9 (11.7%)
Between 1.25 and 1.5 million km2__11 (11.6%)_ 3 (3.8%)
Between 1.0 and 1.25 million km2___1 (01.1%)_ 2 (2.6%)
{Between 0.75 and 1.0 million km2}___________ 6 (7.7%)
{Between 0.5 and 0.75 million km2}___________ 1 (1.3%)
{Between 0.25 and 0.5 million km2}___________ 2 (2.6%)
{Between 0 and 0.25 million km2}_____________ 1 (1.3%)
Less than 1.0 million km2_________10 (10.5%)}

Total number of votes_____________95_________ 78

Median April vote 1.89 M Km^2. Median May vote 1.84 M Km^2

April weighted average 1.81 M Km^2 May weighted average 1.82 M Km^2

All the medians and weighted averages are in the mode category 1.75 to 2 M Km^2.

Median going down but weighted average going up. A strange or interesting effect?

Part of this is perhaps putting all 10 votes for less than a million at 0.5 million whereas the average of 10 lowest votes in May is higher due to popular 0.75 to 1 million category. Another cause is the {edit larger increased popularity} of 2 to 2.25 category in May.

May distribution is tighter near the peak but more disperse away from the peak. I would expect the distribution to get tighter as more information becomes available so it is the more disperse distribution well away from the peak that seems a little unusual. Perhaps the extra choices had some influence on this?

With very little change in the poll averages, medians and mode, it is very difficult to look for causes of changes.

Hope that for the moment this will do for the poll analysis that Neven asked me for.
« Last Edit: June 04, 2013, 10:15:09 AM by crandles »

dree12

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #66 on: June 04, 2013, 05:24:32 AM »
Time to compare April and May polls:

__________________________________April______May
More than 3.5 million km2__________0 (0.00%)_ 0 (0.00%)
Between 3.25 and 3.5 million km2___0 (0.00%)_ 1 (1.3%)
Between 3.0 and 3.25 million km2___2 (02.1%)_ 1 (1.3%)
Between 2.75 and 3.0 million km2___2 (02.1%)_ 1 (1.3%)
Between 2.5 and 2.75 million km2___5 (05.3%)_ 2 (2.6%)
Between 2.25 and 2.5 million km2__11 (11.6%)_ 6 (7.7%)
Between 2.0 and 2.25 million km2__12 (12.6%)_ 19 (24.4%)
Between 1.75 and 2.0 million km2__28 (29.5%)_ 24 (30.8%)
Between 1.5 and 1.75 million km2__13 (13.7%)_ 9 (11.7%)
Between 1.25 and 1.5 million km2__11 (11.6%)_ 3 (3.8%)
Between 1.0 and 1.25 million km2___1 (01.1%)_ 2 (2.6%)
{Between 0.75 and 1.0 million km2}___________ 6 (7.7%)
{Between 0.5 and 0.75 million km2}___________ 1 (1.3%)
{Between 0.25 and 0.5 million km2}___________ 2 (2.6%)
{Between 0 and 0.25 million km2}_____________ 1 (1.3%)
Less than 1.0 million km2_________10 (10.5%)}

Total number of votes_____________95_________ 78

Median April vote 1.89 M Km^2. Median May vote 1.84 M Km^2

April weighted average 1.81 M Km^2 May weighted average 1.82 M Km^2

All the medians and weighted averages are in the mode category 1.75 to 2 M Km^2.

Median going down but weighted average going up. A strange or interesting effect?

Part of this is perhaps putting all 10 votes for less than a million at 0.5 million whereas the average of 10 lowest votes in May is higher due to popular 0.75 to 1 million category. Another cause is the larger 2 to 2.25 category in May.

May distribution is tighter near the peak but more disperse away from the peak. I would expect the distribution to get tighter as more information becomes available so it is the more disperse distribution well away from the peak that seems a little unusual. Perhaps the extra choices had some influence on this?

With very little change in the poll averages, medians and mode, it is very difficult to look for causes of changes.

Hope that for the moment this will do for the poll analysis that Neven asked me for.

The way the poll is worded, people are likely to choose what they believe is most likely. When 0.0 to 1.0 was lumped as a single category, its probability grew to encompass all of its subcategories (0.0 to 0.25, 0.25 to 0.5, etc.). After the lump category was split, some decided to change their votes to more probable categories that were previously suppressed. This might explain the discrepancy in the lower range.

Neven

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #67 on: June 04, 2013, 09:36:42 AM »
Hope that for the moment this will do for the poll analysis that Neven asked me for.

It's excellent, but much earlier than I expected.  :)
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sofouuk

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Re: Cryosphere Today 2013 Arctic SIA daily minimum: May poll
« Reply #68 on: June 04, 2013, 11:43:21 AM »
eyeballing, in April there was a pretty normal distribution across the five most popular bins, that skews towards higher values in May. General assumption then that the slow start will result in a higher than otherwise expected finish, but that the finish will still be pretty low. I wouldn't pay too much attention to trends in the tails tho