Support the Arctic Sea Ice Forum and Blog

Poll

What will the NSIDC 2014 Arctic SIE September minimum be?

Between 5.25 and 5.5 million km2
2 (2.1%)
Between 5.0 and 5.25 million km2
2 (2.1%)
Between 4.75 and 5.0 million km2
6 (6.3%)
Between 4.5 and 4.75 million km2
10 (10.5%)
Between 4.25 and 4.5 million km2
12 (12.6%)
Between 4.0 and 4.25 million km2
18 (18.9%)
Between 3.75 and 4.0 million km2
12 (12.6%)
Between 3.5 and 3.75 million km2
14 (14.7%)
Between 3.25 and 3.5 million km2
6 (6.3%)
Between 3.0 and 3.25 million km2
5 (5.3%)
Between 2.75 and 3.0 million km2
4 (4.2%)
Between 2.5 and 2.75 million km2
2 (2.1%)
Between 2.25 and 2.5 million km2
0 (0%)
Between 2.0 and 2.25 million km2
0 (0%)
Between 1.75 and 2.0 million km2
1 (1.1%)
Between 1.5 and 1.75 million km2
0 (0%)
Between 1.25 and 1.5 million km2
0 (0%)
Between 1.0 and 1.25 million km2
0 (0%)
Between 0.75 and 1.0 million km2
0 (0%)
Between 0.5 and 0.75 million km2
0 (0%)
Between 0.25 and 0.5 million km2
0 (0%)
Between 0 and 0.25 million km2
1 (1.1%)

Total Members Voted: 92

Voting closed: June 11, 2014, 09:15:09 AM

Author Topic: NSIDC 2014 Arctic SIE September minimum: June poll  (Read 30456 times)

Neven

  • Administrator
  • First-year ice
  • Posts: 7869
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 1151
  • Likes Given: 557
NSIDC 2014 Arctic SIE September minimum: June poll
« on: June 01, 2014, 09:15:09 AM »
ATTENTION: There are two polls on the ASIF. One is for NSIDC sea ice extent monthly/September average minimum, the other is for Cryosphere Today sea ice area daily minimum. Make sure you are aware of the difference before voting. You can discuss various extent/area data sets in this dedicated thread.

-----

This NSIDC extent poll will run for 10 days (until June 11th). Until then you can change your vote. There will be a new poll next month.

Here's how things are currently looking based on data up to May 31st:



These are the September minimums for the last 8 years (in millions km2, found here):

    2005: 5.57
    2006: 5.92
    2007: 4.30
    2008: 4.73
    2009: 5.39
    2010: 4.93
    2011: 4.63
    2012: 3.63
    2013: 5.35

You can use the comment thread below to motivate your choice, but discuss various SIE/SIA data sets in this dedicated thread.
« Last Edit: June 24, 2014, 11:23:38 AM by Neven »
Il faut comparer, comparer, comparer, et cultiver notre jardin

Anne

  • Grease ice
  • Posts: 531
    • View Profile
  • Liked: 14
  • Likes Given: 2
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #1 on: June 01, 2014, 09:44:04 AM »
Well, I'll tell you that I won't vote in these polls as I lack the expertise but it pains me that without having voted I can never see the way it's swinging. :)

Neven

  • Administrator
  • First-year ice
  • Posts: 7869
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 1151
  • Likes Given: 557
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #2 on: June 01, 2014, 09:54:40 AM »
Because of last year I'm starting out more or less conservatively, guessing that the minimum will end up near that of 2011: Between 4.5 and 4.75 million km2
Il faut comparer, comparer, comparer, et cultiver notre jardin

icefest

  • Frazil ice
  • Posts: 258
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #3 on: June 01, 2014, 10:30:51 AM »
It's a pity that those who consider themselves less informed cannot tick a box that allows us to vote, but that our vote will not be included in the average.
Open other end.

DavidR

  • Grease ice
  • Posts: 736
    • View Profile
  • Liked: 32
  • Likes Given: 3
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #4 on: June 01, 2014, 11:23:25 AM »
We are all ill-informed of the weather over the next three months. This will be the critical  factor in determining the outcome.  Every novice should have a go to  reflect their assessment  of the information provided here.  It's not a scientific evaluation.
My view, informed by what I've read here and based on Chris Reynolds PIOMAS analysis, is that a low figure this year is easily achievable even with average weather. So I  have opted for an outcome in line with the 2012 minimum. 
Toto, I've a feeling we're not in Kansas anymore

Peter Ellis

  • Grease ice
  • Posts: 619
    • View Profile
  • Liked: 33
  • Likes Given: 14
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #5 on: June 01, 2014, 12:05:49 PM »
In the recent historical record, 2013 seems closest to 2009, ergo my "naive" expectation is that 2014 will be similar to 2010.  There's a lot more thicker ice this year than recently, most of which has been exported into the Beaufort and will act as a "buffer" for the main pack. Yes, synoptics may well be favourable for melt - as they were in 2010. In that case I'd expect to see the same kind of volume crash and loss/thinning of MYI that happened in 2010, but that won't show up in the area/extent data until 2015 or 2016.

TLDR version: 2010 replay, final figures between 4.75 and 5

Peter Ellis

  • Grease ice
  • Posts: 619
    • View Profile
  • Liked: 33
  • Likes Given: 14
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #6 on: June 01, 2014, 12:12:40 PM »
As a follow-up comment - look at the re-freeze curves for 2009/10 and 2013/14.  They're practically identical up to the end of February.  2010 put on more in March and April than 2014 did, but that's thin fringey stuff that's now mostly gone, and so we're back to similar levels of overall coverage.  Proportion and location of MYI is quite similar from 2010 to 2014 (if anything there's more in 2014).  2010 had hideous synoptics for early melt and still didn't show a catastrophic area loss - all the extra heat went into burning back the volume of MYI in the Beaufort.  Look for the same this year.

Rubikscube

  • Frazil ice
  • Posts: 254
    • View Profile
  • Liked: 5
  • Likes Given: 4
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #7 on: June 01, 2014, 01:02:07 PM »
I think many people (me included) got too excited last year when they saw how 2012 could smash all previous records with weather conditions far less favourable than 2007, and now the burnt children dread the fire. Though, with current weather conditions and forecasts, low April snow cover and volume back at 2012 levels, I cannot possibly see how it can get anywhere close to 2013, so I'm jumping right into the fire and forecast 3,0 to 2,75.

OSweetMrMath

  • Frazil ice
  • Posts: 137
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #8 on: June 01, 2014, 08:30:36 PM »
I'm going to hold off on voting until the May monthly data is in, but I can report a bunch of predictions based on the data through April. This is a long post because it includes seven different predictions. If anyone wants to discuss the different prediction techniques, it might be better to do that in the sea ice area and extent data thread. If people think this entire post belongs there instead of here, I can move it.

These are purely statistical predictions based on the available extent data, and do not reflect weather, ice conditions, etc. Note that the behavior of the ice changed in 2007, so the quality of these predictions reflects the ability, or lack thereof, of these predictors to capture that change.

Starting with just the September data for each year, so these predictions could have been made in October and would not have changed, we have: a linear fit predicts 4.8 (million km^2) with 95% confidence interval 3.6-6.0. (Note that I have not attempted to validate any of these confidence intervals.)

If instead we assume there is a constant annual change plus noise (so this September = last September - constant + noise), then the prediction is 5.3 with 95% CI 3.8-6.8. This value is high primarily because last year's extent was high.

If we fit a smoothing spline to the September data, the spline tracks the change in 2007 better than the other predictors, so predicts this year will be 4.4. I have not computed the 95% CI, but it is likely to be substantially larger than the other predictors.

If we build an ARIMA time series model for the September data, we predict 4.6, with 95% CI 3.5-5.7.

If we look at all of the data, the first thing we can try is taking the average change from April to September as a prediction of the change this year. Unfortunately, this does not reflect the changing ice behavior well, and predicts 5.8 with 95% CI 4.1-7.5. On the other hand, this should improve as we get closer to September, unlike the previous predictions.

Computing the monthly anomaly and fitting a smoothing spline fails for the same reason, predicting 5.5. As usual, I have not computed the CI for the spline, but it is likely to be very large. The spline does not track the data since 2007 well, and this is unlikely to improve even as more data comes in for the rest of the year.

Finally, fitting a SARIMA time series model to all of the monthly data predicts 4.7, with 95% CI 4.0-5.4. Frankly, I think CI is overoptimistically small, but the accuracy of the prediction should improve as the year goes on.

Once the May monthly data is available, I will update the SARIMA prediction and use that as my prediction.

cats

  • New ice
  • Posts: 48
    • View Profile
  • Liked: 0
  • Likes Given: 5
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #9 on: June 01, 2014, 09:17:54 PM »
At this point in time I am being much more "conservative" than last year and ticked the 4.5-4.75 box.  That said, I expect June to be a telling month for where the extent will finally end up.  Ice seems very fractured and weak to me (eyeball observations of MODIS), but hard to say if that will equate to a big melt - will wait and see how the June weather turns out.

SteveMDFP

  • Nilas ice
  • Posts: 1888
    • View Profile
  • Liked: 415
  • Likes Given: 26
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #10 on: June 02, 2014, 12:25:55 AM »
3.51.  Just as with my post on the CT one-day poll, a new record by a modest margin, all the listed reasons apply.

There is, in my mind, one more reason that I didn't list there.  If I recall correctly, ice minimum numbers show a one-year statistical autocorrelation.  Thus, a melt beyond trend in 2012 was followed by a notably anemic melt in 2013.  So I'm thinking of a bouncing ball -- a notably anemic melt should now be followed by aggressive melt. 

icebgone

  • New ice
  • Posts: 58
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #11 on: June 02, 2014, 01:46:14 AM »
I'm going with the statistical 4.8 for now.  I am watching the Siberian fire situation.  Haze from smoke and soot falling onto bare ice have opposite effects.  It will be interesting to see which has the greater melt impact.  Also, is there a measurement of how much energy is being injected via Pacific water flowing through the Bering Strait?  I seem to remember an estimate of 4-7 PetaJoules for a situation similar to what happened on the Pacific side this year in 2010?  If so, ice volume could be an interesting guess come October.

Yuha

  • Frazil ice
  • Posts: 313
    • View Profile
  • Liked: 62
  • Likes Given: 27
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #12 on: June 02, 2014, 01:53:07 AM »
4.49 as the average of the 2012 and 2013 figures.

Juan C. García

  • Nilas ice
  • Posts: 2289
    • View Profile
  • Liked: 1104
  • Likes Given: 787
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #13 on: June 02, 2014, 04:29:17 AM »
Between 4.25 and 4.5 million km2.
Just a guess...
Which is the best answer to Sep-2012 ASI lost (compared to 1979-2000)?
50% [NSIDC Extent] or
73% [PIOMAS Volume]

Volume is harder to measure than extent, but 3-dimensional space is real, 2D's hide ~50% thickness gone.
-> IPCC/NSIDC trends [based on extent] underestimate the real speed of ASI lost.

jonthed

  • New ice
  • Posts: 69
    • View Profile
  • Liked: 1
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #14 on: June 02, 2014, 05:50:51 AM »
4.0 - 4.25

Betting on a decent decline but stubborn ice in the Beaufort preventing anything too dramatic. Also pathetic ice floes ruining it.

Lord M Vader

  • Nilas ice
  • Posts: 1334
    • View Profile
  • Liked: 48
  • Likes Given: 29
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #15 on: June 02, 2014, 05:29:00 PM »
As I have said in earlier posts, I believe the minimum will end up somewhere in the range of 3,9-4,5 Mn km2. Therefore I vote for 4,0-4,25 Mn km2 as the likely outcome.

Would be very interesting to know who the extraordinary brave one was who voted for an ice free Arctic? :)

//LMV

OSweetMrMath

  • Frazil ice
  • Posts: 137
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #16 on: June 02, 2014, 10:58:07 PM »
I've updated my SARIMA forecast based on the May data. The May actual was 12.78 million sq. km, compared to my predicted 12.80 million sq. km. Therefore, the change in the September predicted value is less than a rounding error, so my predicted minimum is 4.7 million sq. km, with 95% confidence interval of 4.0-5.4 million sq. km.

LRC1962

  • Frazil ice
  • Posts: 436
    • View Profile
  • Liked: 8
  • Likes Given: 1
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #17 on: June 04, 2014, 06:37:29 AM »
Being an uneducated pessimist, I voted for 3.25-3.5. I think we will be in for a record breaker year. Said the same thing last year, but the weather got in the way. Reasons:
1) Do not think we will have repeat of last years weather.
2) Most of extent came in the last 2-3 weeks of Mar. and therefore very bad ice.
3) Am not convinced the MYI has any quality to it at all and therefore will break apart very easily.
4) Changing conditions in South Pacific will effect things in the Arctic although that could be more next year then this.
5) I am just a pessimist led by a government that believes if you ignore the truth it wont happen.
"All truth passes through three stages: First, it is ridiculed; Second,  it is violently opposed; and Third, it is accepted as self-evident."
       - Arthur Schopenhauer

Nightvid Cole

  • Frazil ice
  • Posts: 437
    • View Profile
  • Liked: 5
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #18 on: June 05, 2014, 11:53:32 PM »
I do not expect a minimum below 2012 this year any more, due to cold weather in the last week of May over Beaufort/Chukchi and the fact that we've never broken the extent record in a year without highly melt-favoring weather in late May and early June.

That said, I'm not expecting a "healthy" ice pack either, given that gridded PIOMAS for last month is showing the area of ice more than 2 meters thick to be quite limited, and recent years generally have most ice that thin in May being lost that season. I don't expect that "rule" to be broken this year, since the weather pattern in the crucial early melt season is quite unremarkable either way.

So, on balance, I voted 3.75 - 4 million km^2.

ChrisReynolds

  • Nilas ice
  • Posts: 1714
    • View Profile
    • Dosbat
  • Liked: 2
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #19 on: June 08, 2014, 12:13:32 PM »
I've got my SIPN proforma filled out and this is the prediction (based on May PIOMAS volume in the Arctic Ocean) that I'm seriously thinking about sending off.

NSIDC Extent: 4.06 +/-0.57, M km2. The range being Upper limit 4.62M km2, lower limit 3.48M km2. EDIT - slip up in calculations figures updated.

I've just voted for the 3.75 bucket, looks like I'm in the middle of the distribution for the board for now. But my main prediction is in terms of CT Area in about two weeks from now  - that takes precedence over this one.

Well, I've done it, the SIPN submision has just gone off.
« Last Edit: June 08, 2014, 09:41:25 PM by ChrisReynolds »

Frivolousz21

  • Nilas ice
  • Posts: 1848
  • Live in Belleville, IL..15 miles SE of St. Louis.
    • View Profile
  • Liked: 552
  • Likes Given: 6
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #20 on: June 08, 2014, 12:29:56 PM »
The not so nICE King voted for:

Between 4.5 and 4.75 million km2
I got a nickname for all my guns
a Desert Eagle that I call Big Pun
a two shot that I call Tupac
and a dirty pistol that love to crew hop
my TEC 9 Imma call T-Pain
my 3-8 snub Imma call Lil Wayne
machine gun named Missy so loud
it go e-e-e-e-ow e-e-e-e-e-e-blaow

DoomInTheUK

  • Frazil ice
  • Posts: 221
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #21 on: June 08, 2014, 01:19:12 PM »
I'm using the tried and trusted method of a total guess.

3.8

Working on the principle that things are never quite as influential as you imagine (both good and bad), and that something unusal always turns up before the final curtain.

In the same vain, I also have a feeling that the minimum will be reached later than average.

Nick_Naylor

  • Frazil ice
  • Posts: 291
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #22 on: June 08, 2014, 10:25:45 PM »
Global warming is the greatest hoax ever perpetuated on mankind, and I too believe that cigarettes are not addictive.

That said, the minimum will be 3.7 this year and 0.6 next year.

Steven

  • Grease ice
  • Posts: 634
    • View Profile
  • Liked: 199
  • Likes Given: 17
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #23 on: June 09, 2014, 05:10:55 PM »
5.0 million km2.   (I voted 4.75-5.00)

The Arctic has been relatively cold in the past few weeks, at a critical time in the melt season.

So the onset of surface melting and melt pond formation this year may be relatively slow compared to recent years.

The PIOMAS volume within the Arctic Ocean (excluding regions like Hudson Bay) is still among the lowest years on record.  But the amount of multi-year ice is relatively high, and it remains to be seen how much of that will melt out by September.
« Last Edit: June 09, 2014, 05:19:34 PM by Steven »

Neven

  • Administrator
  • First-year ice
  • Posts: 7869
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 1151
  • Likes Given: 557
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #24 on: June 09, 2014, 05:19:39 PM »
I agree with Steven and went up a notch: 4.75-5.0 million km2
Il faut comparer, comparer, comparer, et cultiver notre jardin

DavidR

  • Grease ice
  • Posts: 736
    • View Profile
  • Liked: 32
  • Likes Given: 3
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #25 on: June 09, 2014, 10:51:25 PM »
@Chris Reynolds,
I  have just  submitted my SIPN projection based on your April PIOMAS data and I  am sticking with 3-3.25 M Km2 with a range of 2.5 - 3.8.
Toto, I've a feeling we're not in Kansas anymore

CraigsIsland

  • Frazil ice
  • Posts: 201
    • View Profile
  • Liked: 1
  • Likes Given: 9
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #26 on: June 10, 2014, 08:44:30 AM »
I see it going below 2012 with ease. Too thin and too much heat for ice to survive.

slow wing

  • Grease ice
  • Posts: 819
    • View Profile
  • Liked: 155
  • Likes Given: 525
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #27 on: June 10, 2014, 01:01:58 PM »
This early, I just took the 2012 and 2013 values as minus and plus one sigma, respectively.

So 4.49 +/- 0.86 million square kilometres.

That falls within the "4.25-4.50" bin.

ChrisReynolds

  • Nilas ice
  • Posts: 1714
    • View Profile
    • Dosbat
  • Liked: 2
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #28 on: June 10, 2014, 08:15:18 PM »
@Chris Reynolds,
I  have just  submitted my SIPN projection based on your April PIOMAS data and I  am sticking with 3-3.25 M Km2 with a range of 2.5 - 3.8.

Glad you found it useful. Was the method heuristic or numeric?

ChrisReynolds

  • Nilas ice
  • Posts: 1714
    • View Profile
    • Dosbat
  • Liked: 2
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #29 on: June 10, 2014, 08:49:56 PM »
5.0 million km2.   (I voted 4.75-5.00)

The Arctic has been relatively cold in the past few weeks, at a critical time in the melt season.

So the onset of surface melting and melt pond formation this year may be relatively slow compared to recent years.

The PIOMAS volume within the Arctic Ocean (excluding regions like Hudson Bay) is still among the lowest years on record.  But the amount of multi-year ice is relatively high, and it remains to be seen how much of that will melt out by September.

PIOMAS volume for Arctic Ocean, including CAA.

2007   20.351
2008   21.201
2009   21.149
2010   20.025
2011   18.781
2012   19.074
2013   19.067
2014   18.986

Strictly speaking it's the second lowest on record. But due to PIOMAS uncertainties it's best to consider it similar to the other post 2011 years. How much melts out in September is weather dominated, but if we do have a repeat of 2013's weather we'll have a similar increase of volume from the other post 2010 years.

OSweetMrMath

  • Frazil ice
  • Posts: 137
    • View Profile
  • Liked: 0
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #30 on: June 10, 2014, 09:45:25 PM »
My vote (4.5-4.75) is based on my prediction based on the monthly data, which currently predicts 4.7 million sq km. However, the prediction includes monthly values for every month until September. Up through May, the actual values have tracked the 2011 values fairly closely, and the predicted values continue to track the 2011 values. But the extent so far in June this year has been quite a bit above the extent in 2011 in June. I'm not going to change my vote, but if I were to make a snap judgment based on the first week of June, I would consider increasing to 4.75-5.0.

Michael Hauber

  • Grease ice
  • Posts: 900
    • View Profile
  • Liked: 76
  • Likes Given: 14
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #31 on: June 11, 2014, 12:59:26 PM »
Was going to vote 4-4.25 but looks like I was too slow.

We are behind 2007 and 2012 in surface melt and general ice quality as best I can judge, but I think we are equal with other years, and definitely ahead of 2013.  Given 2007 was 7 years ago and had the thicker ice pack to deal with I think we should still be in with a good chance of beating 2007.  The Laptev bite is huge and late season should make it a good chance to break down the tongue of ice towards the East Siberian Sea - which has been present in all years other than 2007 and 2012.  If we have a low pressure dominated rest of melting season the rotation will push the open water in the Laptev towards this region.

The weather this year seems to be variable with alternating bouts of good and bad melting weather.  We had the polar vortex move over America in winter, and now with summer in full swing there is hints of the coldest air moving into Atlantic - America was colder in winter, but now with summer the Atlantic will be colder than America, so perhaps there is a reason for this switch.  If the polar vortex wanders into the Atlantic in a similar manner to its winter trips to America the melt season could be given a serious boost.

The current pattern has a series of lows pushing in from Siberia through the center of the Arctic and out to the Atlantic.  Although it brings cooler and cloudier conditions as in 2013, the troughing, and movement of the pressure systems results in more heat being pulled from nearby land masses, and increased export ice into the Atlantic, while still tending to cause diversion and holes in the ice pack.  If the variation in weather follows up with sunshine then instead of the sun warming up a large area of open water to 5 or 10 degrees the heat in the water will quickly have an ice floe travel over it and the energy will melt ice instead.  There has been a lot of movement of ice out into the Barents sea since at least spring, and the divergence between this movement and the transport of ice down the coast of Greenland is probably part of why the Atlantic side of the central Arctic is looking a little raggy.
Climate change:  Prepare for the worst, hope for the best, expect the middle.

Steven

  • Grease ice
  • Posts: 634
    • View Profile
  • Liked: 199
  • Likes Given: 17
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #32 on: June 11, 2014, 06:28:32 PM »
PIOMAS volume for Arctic Ocean, including CAA.

2007   20.351
2008   21.201
2009   21.149
2010   20.025
2011   18.781
2012   19.074
2013   19.067
2014   18.986

Strictly speaking it's the second lowest on record. But due to PIOMAS uncertainties it's best to consider it similar to the other post 2011 years.  .....

Thanks for clarifying this, Chris.  Sorry if my phrase "among the lowest years on record" was unclear; I meant 2011-2014.  Last week I was playing around with your regional volume spreadsheet, and with the same values as in the above quote (for the last few decades).

FWIW, linear regression on these data (for the last 10 or 20 years or so) suggests about 4.4 or 4.5 million km2 for the September extent this year.  Standard error of the regression is about 0.5 or 0.6 million km2.  A quadratic fit with all these volume data from 1979 onward suggests about 4.4 for the September extent.  Using the May 31st PIOMAS values (instead of the May monthly averages), over the full PIOMAS domain, suggests about 4.6 million km2.
 
« Last Edit: June 11, 2014, 07:55:50 PM by Steven »

Steven

  • Grease ice
  • Posts: 634
    • View Profile
  • Liked: 199
  • Likes Given: 17
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #33 on: June 11, 2014, 08:07:11 PM »
P.S. It seems reasonable to ignore the ice volume in regions like Hudson Bay in the calculations.  On the other hand the Overland et al. paper that was discussed recently, mentions the earlier melt of sea ice in Hudson Bay as a speculative but possible contributing driver of the Arctic Dipole.

Speculatively, maybe for similar reasons it could be interesting to work with a weighted mean that assigns a higher weight to regions like Kara and Laptev Sea, compared to other regions...

My guesstimate in Reply #23 was heuristic; it seems hard to find numerical data on the amount of multi-year ice, early melt season weather, current snow depths etc.  Of course it's possible that I was erring on the high side.  Anyway, it will be interesting to see what weather we will have in the next weeks and months.
 
« Last Edit: June 12, 2014, 12:57:03 AM by Steven »

DavidR

  • Grease ice
  • Posts: 736
    • View Profile
  • Liked: 32
  • Likes Given: 3
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #34 on: June 12, 2014, 10:26:08 AM »
@Chris Reynolds,
I  have just  submitted my SIPN projection based on your April PIOMAS data and I  am sticking with 3-3.25 M Km2 with a range of 2.5 - 3.8.

Glad you found it useful. Was the method heuristic or numeric?
Heuristic, I think.
I  reversed engineered your graph to determine the average melt thickness for the past three years. This was surprisingly  consistent up until July 31 at 1.75-1.85 m.  Then it  varies between 10 and 50 cm until the minimum.
I  have predictions every  fortnight till  Jul 31 and so  far we seem to  be on track.
For my  estimate I calculated the extent loss up to Jul 31, which  should be greater than 2012 and then added in another 20 cm melt (a bit  below average) in August  September to  estimate the total loss for the year. The range is 10-30cm of melt in that  period.  If it  pans out that  way it will blow the 2012 records out  of the water.
Toto, I've a feeling we're not in Kansas anymore

ChrisReynolds

  • Nilas ice
  • Posts: 1714
    • View Profile
    • Dosbat
  • Liked: 2
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #35 on: June 13, 2014, 07:44:32 AM »
Thanks David,

Rather than reverse engineering I may be able to get you numbers, what graph do you mean? I would call such a method numeric with a heuristic component.

Steven,

In my submission I make it clear that I take the AD development as a given, which is why I didn't factor it in explicitly - I can't find a reliable predictor. So far there's no indication of it, however June SLP so far shows Beaufort having high pressure and an enhanced Beaufort high is part of the pattern, Greenland is starting to show high pressure.

DavidR

  • Grease ice
  • Posts: 736
    • View Profile
  • Liked: 32
  • Likes Given: 3
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #36 on: June 13, 2014, 08:10:45 AM »
Estimate of likely course of melt season using the following graph from DOSBAT.
http://dosbat.blogspot.com.au/2014/05/piomas-april-2014-gridded-data.html



Chris,
This is the graph I  used.
(I need to work out how to post my own images here).
Graphing my estimates, puts the crossover between 2012 and 2014, as occurring sometime last weekend.  Which is not bad for a prediction based on April averages.
Next data point is 2014 extent matching 2013 in the first  week of July.
I  told someone else I'd look at real data over winter if my estimates looked reasonable at the end of the season.
Regards
Toto, I've a feeling we're not in Kansas anymore

ChrisReynolds

  • Nilas ice
  • Posts: 1714
    • View Profile
    • Dosbat
  • Liked: 2
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #37 on: June 13, 2014, 06:37:47 PM »
Hi David,

The raw figures are here:
http://dosbat.blogspot.co.uk/2013/12/regional-piomas-volume-data.html
You'll need "Regional Volume Breakdowns V2.1", scroll down to the heading 'The Data' and there's a link to a Google Drive page with CSV files.

I don't understand how you're getting melt volumes from that April data though.

Peter Ellis

  • Grease ice
  • Posts: 619
    • View Profile
  • Liked: 33
  • Likes Given: 14
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #38 on: June 19, 2014, 10:40:32 AM »
Neven, can we get some more figures at the high end for next month's poll?  Right now the ice in the CAB (aside from the Laptev polynya) is looking in better shape even than 2013.  Virtually no melt ponding, and no visible lead in the Basin centre around the Pole, where last year had noticeable fracturing/loosening of the pack by now.

This year's start has been sufficiently slow that I'm considering we may beat last year.

Neven

  • Administrator
  • First-year ice
  • Posts: 7869
    • View Profile
    • Arctic Sea Ice Blog
  • Liked: 1151
  • Likes Given: 557
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #39 on: June 19, 2014, 10:42:37 AM »
Peter, I'll put in 2 more bins at the top for the July poll.
Il faut comparer, comparer, comparer, et cultiver notre jardin

Jim Hunt

  • First-year ice
  • Posts: 5079
  • Stay Home, Save Lives
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 573
  • Likes Given: 55
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #40 on: June 19, 2014, 11:49:18 AM »
Virtually no melt ponding. This year's start has been sufficiently slow that I'm considering we may beat last year.

I cannot help but wonder if you and I are looking at the same ice Peter. By way of example see:

http://forum.arctic-sea-ice.net/index.php/topic,778.msg28776.html#msg28776

and

http://forum.arctic-sea-ice.net/index.php/topic,778.msg28891.html#msg28891
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Peter Ellis

  • Grease ice
  • Posts: 619
    • View Profile
  • Liked: 33
  • Likes Given: 14
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #41 on: June 19, 2014, 12:05:15 PM »
I'm looking at the broader view and lower magnification rather than an a close-up of the areas where 2014 is ahead.

Take the overview of the whole Arctic basin, here:
2013: http://1.usa.gov/1oJLJ9N
2014: http://1.usa.gov/SVLPvW

2013 has a broad sweep of blue/grey ice all along the northern coast of Canada.  Still bright white in 2014, indicating less melt ponding.

At slightly higher magnification (but still a wide enough view to be representative), across between the Pole and Barentsz Sea, we have this:
2013: http://1.usa.gov/1oJM0JK
2014: http://1.usa.gov/SVLWaS

2013 is loose, fragmented and mobile with very wide leads in places. For 2014 you can see the floe structure, but it's still pretty contiguous with few leads wider than 1 or 2 pixels.

Overall I don't think there's much to choose between them - and that's certainly the case on both area and extent. Couple that with the knowledge that we have more multi-year ice this year than last, and the very cold temperatures for the year to date, and I don't see that we will be much lower than last year.

Wipneus

  • Citizen scientist
  • Young ice
  • Posts: 4172
    • View Profile
    • Arctische Pinguin
  • Liked: 946
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #42 on: June 19, 2014, 12:17:01 PM »
I largely agree with Peter. Here is the (AMSR2 ASIv6) CAB ice concentration of today compared with a year ago. I still think 2013 looks rather promising here (for a great melt).

(click for an animation)

Jim Hunt

  • First-year ice
  • Posts: 5079
  • Stay Home, Save Lives
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 573
  • Likes Given: 55
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #43 on: June 19, 2014, 12:28:44 PM »
Couple that with the knowledge that we have more multi-year ice this year than last, and the very cold temperatures for the year to date, and I don't see that we will be much lower than last year.

The temperatures were actually "very warm" all through the "freezing season":

http://GreatWhiteCon.info/2014/04/the-arctic-sea-ice-recovery-vanishes-even-more/

Consequently the current "multi-year ice" isn't awfully thick:

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/summer-2014-imbs/#2013F

Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Peter Ellis

  • Grease ice
  • Posts: 619
    • View Profile
  • Liked: 33
  • Likes Given: 14
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #44 on: June 19, 2014, 02:20:27 PM »
Well, we shall see at the end of the season.

Jim Hunt

  • First-year ice
  • Posts: 5079
  • Stay Home, Save Lives
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 573
  • Likes Given: 55
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #45 on: June 19, 2014, 04:28:37 PM »
Well, we shall see at the end of the season.

We shall indeed!

In the meantime your view seems to be based on your previous comment that "There's a lot more thicker ice this year than recently, most of which has been exported into the Beaufort". Since I've presented some evidence suggesting that is not in fact the case, I was rather hoping you would be able to reveal some facts and figures to prove me wrong.
Reality is merely an illusion, albeit a very persistent one - Albert Einstein

Peter Ellis

  • Grease ice
  • Posts: 619
    • View Profile
  • Liked: 33
  • Likes Given: 14
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #46 on: June 19, 2014, 05:57:06 PM »
The only solid data we have on basin-wide thickness is the December release from CryoSat which showed a large increase in Autumn/Winter thickness over last year. The QuickLook CryoSat data (more recent) and IceBridge measurements also show significant increases in thickness, as covered by the NSIDC here:
http://nsidc.org/arcticseaicenews/2014/06/low-north-high-south/

From April, we have the ice drift model outputs showing where the MYI is located, and this was readily confirmed from radar satellite data at the time.
http://nsidc.org/arcticseaicenews/2014/04/

For modelled volume, PIOMAS also had this year well above last until about March.  It may be that we've had dramatic thickness losses since then and consequently "caught up" volume-wise, but I'd be a little sceptical about that given the lack of melt ponding and overall more contiguous ice pack (as I linked in my previous post).  However you cut it, current area, extent and volume either are (or are modelled to be) pretty similar from last year to this.

You've linked to one buoy in second-year ice as evidence that the multi-year ice didn't thicken much last winter.  First of all, second-year ice only just counts as multi-year. More significantly, a buoy cannot by its very nature tell you about MYI thickening.  First-year ice thickens largely by freezing, which a buoy can see. MYI thickens by mechanical deformation and ridging, which is a spatially heterogeneous process.  If the patch of ice containing the buoy becomes deformed/ridged, it will destroy the buoy! So a buoy cannot observe MYI thickening.

DavidR

  • Grease ice
  • Posts: 736
    • View Profile
  • Liked: 32
  • Likes Given: 3
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #47 on: June 21, 2014, 10:09:59 AM »
How to  be top!
The summary of all the contributions to the SIPN prediction of the Arctic Sea ice extent minimum is  here:
http://www.arcus.org/sipn/sea-ice-outlook/2014/june
The listed the predictions by lowest first and I got to the top of the list.
Scary!!!

Toto, I've a feeling we're not in Kansas anymore

ChrisReynolds

  • Nilas ice
  • Posts: 1714
    • View Profile
    • Dosbat
  • Liked: 2
  • Likes Given: 0
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #48 on: June 21, 2014, 09:57:59 PM »
Ah! Right I was looking for you but didn't know that was your surname.

Good luck - I think we'll both need it!

Jim Hunt

  • First-year ice
  • Posts: 5079
  • Stay Home, Save Lives
    • View Profile
    • The Arctic sea ice Great White Con
  • Liked: 573
  • Likes Given: 55
Re: NSIDC 2014 Arctic SIE September minimum: June poll
« Reply #49 on: June 23, 2014, 01:35:06 PM »
The only solid data we have on basin-wide thickness is the December release from CryoSat which showed a large increase in Autumn/Winter thickness over last year.

IceBridge seems to show large areas of the Beaufort Sea under 2 m thick?

http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#IceBridgeThick

Quote
From April, we have the ice drift model outputs showing where the MYI is located, and this was readily confirmed from radar satellite data at the time.

ASCAT shows lots of MYI has been exported from the CAB in the direction of the North Atlantic, and FYI from the Russian side now reaches as far as the North Pole?

http://GreatWhiteCon.info/resources/arctic-sea-ice-videos/summer-2014-videos/#ASCAT

Quote
However you cut it, current area, extent and volume either are (or are modelled to be) pretty similar from last year to this.

The area/extent in the regions that ultimately count is significantly less than 2013?

http://GreatWhiteCon.info/resources/arctic-sea-ice-graphs/#ExtentRegions

Quote
You've linked to one buoy in second-year ice as evidence that the multi-year ice didn't thicken much last winter.  First of all, second-year ice only just counts as multi-year. More significantly, a buoy cannot by its very nature tell you about MYI thickening.  First-year ice thickens largely by freezing, which a buoy can see. MYI thickens by mechanical deformation and ridging, which is a spatially heterogeneous process.  If the patch of ice containing the buoy becomes deformed/ridged, it will destroy the buoy! So a buoy cannot observe MYI thickening.

A buoy cannot observe MYI thickening, but it can keep an eye on thermodynamic thickening of second year ice during the freezing season. Last winter was remarkably warm, which may explain why currently second year ice seems to be remarkably thin, and why bottom melt has started remarkably early this year?

http://GreatWhiteCon.info/resources/ice-mass-balance-buoys/#Table
Reality is merely an illusion, albeit a very persistent one - Albert Einstein