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What will the NSIDC 2013 Arctic SIE September minimum be?

More than 5.0 million km2
2 (3.8%)
Between 4.75 and 5.0 million km2
4 (7.7%)
Between 4.5 and 4.75 million km2
4 (7.7%)
Between 4.25 and 4.5 million km2
7 (13.5%)
Between 4.0 and 4.25 million km2
10 (19.2%)
Between 3.75 and 4.0 million km2
13 (25%)
Between 3.5 and 3.75 million km2
5 (9.6%)
Between 3.25 and 3.5 million km2
2 (3.8%)
Between 3.0 and 3.25 million km2
2 (3.8%)
Between 2.75 and 3.0 million km2
2 (3.8%)
Between 2.5 and 2.75 million km2
0 (0%)
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
0 (0%)
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 (1.9%)

Total Members Voted: 49

Voting closed: August 11, 2013, 06:10:15 PM

Author Topic: NSIDC 2013 Arctic SIE September minimum: August poll  (Read 145985 times)

Neven

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NSIDC 2013 Arctic SIE September minimum: August poll
« on: August 04, 2013, 06:10:15 PM »
THIS POLL WILL RUN FOR ONE WEEK (until August 11th). YOU CAN CHANGE YOUR VOTE. MIND THE DIFFERENCES WITH CT SEA ICE AREA DAILY MINIMUM. THIS IS THE NSIDC SEA ICE EXTENT MONTHLY/SEPTEMBER MINIMUM.

Attention: Because it's this year's last poll, you have only one week to vote!


Here's my standard poll text:

It should be 'fun' and interesting to hold a poll each month, to see how opinions change according to sea ice rhythm and pace. These monthly polls can then also function as a dedicated thread for everything concerning NSIDC sea ice extent.

Again, this poll is for NSIDC sea ice extent monthly minimum (unlike the other popular measure: Cryosphere Today sea ice area daily minimum), so we're looking for the average Arctic sea ice extent number for September 2013.

Here's how things are currently looking based on data up to August 3rd:



These are the September minimums for the last 7 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: 3.61

Again, try to use this thread to discuss NSIDC SIE mainly. There are other threads for the other topics, and if there isn't, feel free to open one.
« Last Edit: August 04, 2013, 09:31:56 PM by Neven »
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Neven

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #1 on: August 04, 2013, 06:11:14 PM »
Went up another bin to 3.75-4.0, like the coward that I am.  ;D 8)
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BornFromTheVoid

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #2 on: August 04, 2013, 06:22:31 PM »
Update for the week to August 3rd

The current 1 day extent is 6,679,830km2, while the 5 day mean is on 6,944,968km2
 
The daily anomaly (compared to 79-11) is at -1,253,840km2, an increase from -1,239,170km2 last week. The anomaly compared to the 07, 11 and 12 average has decreased from 517,153km2 to 435,720km2 this week. We're currently 5th lowest on record, down from 6th lowest last week.
 
The average daily loss over the last 7 days was 85.0k/day, compared to the long term average of 82.9k/day, and the average of the last 5 years of 73.0k/day.

The average long term loss over the next week is 69.0k/day, with the average of the last 5 years being 87.5k/day.

July experienced the 6th largest loss on record, at 3,052,420km2, which was 347,870km2 above the 79-11 average.
The loss so far this August is the largest on record, at -416,600km2. We need to average a loss of 82.2k/day for the remainder of the month to record the largest August extent drop on record.

The current extent is below the annual daily minima of 12 out of 34 previous years, and within 1 million km2 of another 14.





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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #3 on: August 04, 2013, 06:26:32 PM »
THIS POLL WILL RUN FOR TWO WEEKS (until July 20th). YOU CAN CHANGE YOUR VOTE. MIND THE DIFFERENCES WITH CT SEA ICE AREA DAILY MINIMUM. THIS IS THE NSIDC SEA ICE EXTENT MONTHLY/SEPTEMBER MINIMUM.

Attention: Because it's this year's last poll, you have only one week to vote!

OK, I'm confused.  The poll runs for two weeks, until July 20, which is two weeks ago?  So is the poll only for people traveling backwards in time?   

And it's a two week poll, but we have only one week to vote?  What happens during the second week?

 :)

Neven

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #4 on: August 04, 2013, 06:50:05 PM »
Bloody hell... Fixing...  :-[ ;)
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Richard Rathbone

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #5 on: August 04, 2013, 09:24:12 PM »
Up one or stick with 3.75-4?

PIOMAS shows a little bit less melt than had projected it would at this time when I picked 3.75 to 4 in the last couple of months.

Don't you just hate changing your mind and then finding you would have been right if you stuck with the first guess? :)

Even so, up 1. 4-4.25

("data up to July 2nd" in the caption needs fixing too Neven)



Neven

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #6 on: August 04, 2013, 09:33:47 PM »
The CT SIA August poll is proof that I can do it right too.  :)
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BornFromTheVoid

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #7 on: August 05, 2013, 04:21:12 PM »
Another decent fall on the latest update, 83.2k. That takes us to just 43.6k off the last average of the last 5 years, and to 383k off the 2007, 11 and 12 average.
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Tor Bejnar

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #8 on: August 05, 2013, 05:10:26 PM »
Towel is thrown in.  I'm hiding midst the masses at 3.75-4.0.  (I know I don't know anything any more.)
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #9 on: August 05, 2013, 05:22:03 PM »
I had to go with 4.25-4.5.  I think this year is mirroring 2007 pretty closely and I think that we will, in fact, end up with a bit more ice than that year.  Moreover, it just appears as though there the intense contributors to the massive ice loss last year are just not there.  Sure it has been warm in certain spots, but it's looking like the ice pack will have made it though this summer in better shape than the previous ones. 
pls!

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #10 on: August 05, 2013, 05:44:15 PM »
I am forecasting 4.8 million for the minimum.

Reason 1: Not enough heat was absorbed during the insolation period this spring and summer, and Arctic amplification due to albedo effects is a well established scientific theory.

Reason 2: Although the storm this week will do a great deal of damage to the pack, there is too much ice in the E. Siberian, Chukchi, and Beaufort regions protecting the CAB pack. I expect a lot of August melt, probably approaching 2.0 million in extent loss (exceeding 2011 or 2007 or any other year except 2012's extraordinary 2.7 million). But August started with 6.9 million, and even a huge loss of 2.0 million only drop the SIE to 4.9 million going into September. And I don't expect a lot of extent loss in September.

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #11 on: August 06, 2013, 03:57:25 PM »
An increase in extent for yesterday, of 36.8k.

This makes it the 13th day in a row, that the rolling 7 day loss has been below the 1981-2010 average.
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #12 on: August 06, 2013, 04:14:25 PM »
Well, the numbers that I generate seem to be almost exact. Here is the regional split:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -3.3                    -8.2                   -14.0
               Kara Sea             Barents Sea           Greenland Sea
                    9.0                     0.6                     4.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.5                     0.0                    48.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   -6.4                     7.0                     1.2
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    36.8



Spot the strange region.

BornFromTheVoid

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #13 on: August 06, 2013, 04:19:37 PM »
I suspect a downward correction in Hudson shall be forthcoming then!
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #14 on: August 06, 2013, 04:21:22 PM »
You mean it is not freezing over already?  :P
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #15 on: August 06, 2013, 05:11:49 PM »
I suspect a downward correction in Hudson shall be forthcoming then!

Not likely, the odd value seems to be that of yesterday, and we see a return to the normal:

      YYYYMMDD Hudson.Bay.extent
12694 20130727        0.14442190
12695 20130728        0.13316434
12696 20130729        0.13465783
12697 20130730        0.14274020
12698 20130731        0.14506178
12699 20130801        0.15058082
12700 20130802        0.15312430
12701 20130803        0.15579403
12702 20130804        0.09494628
12703 20130805        0.14387310

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #16 on: August 06, 2013, 05:34:24 PM »
Ah right, cheers. So the previous day's drop was largely from the (likely) false reading over Hudson.

Seems a bit odd that the extent there has been increasing up to the 3rd. Has the area been dropping during that time?
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #17 on: August 06, 2013, 06:24:41 PM »
Here is extent and area from NASA Team, 25km NSIDC concentration data:

      YYYYMMDD Hudson.Bay.extent Hudson.Bay.area
12694 20130727        0.14442190      0.05727353
12695 20130728        0.13316434      0.05704372
12696 20130729        0.13465783      0.05471853
12697 20130730        0.14274020      0.05662371
12698 20130731        0.14506178      0.05124581
12699 20130801        0.15058082      0.05476029
12700 20130802        0.15312430      0.05239694
12701 20130803        0.15579403      0.05702284
12702 20130804        0.09494628      0.03313920
12703 20130805        0.14387310      0.04678607


And here AMSR2 3.125km from Uni-Hamburg:

    YYYYMMDD Hudson.Bay.extent Hudson.Bay.area
208 20130727        0.06336503      0.04684169
209 20130728        0.06818400      0.05517670
210 20130729        0.06405053      0.05255482
211 20130730        0.06174467      0.05225263
212 20130731        0.05763885      0.03971497
213 20130801        0.05258174      0.03550991
214 20130802        0.05737624      0.03803601
215 20130803        0.05595477      0.04377366
216 20130804        0.04812558      0.03893992
217 20130805        0.04495361      0.03027161


Not only have the trends different signs, but also different extents with similar area's. I think we are seeing here the effect of the widely different grid sizes.

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #18 on: August 06, 2013, 08:00:03 PM »
I voted for 4.75-5.00.  I went up two bins compared to last month.

Here is some of the rationale: I used

(1) CT sea ice area data from the last 3 months,
(2) The latest monthly PIOMAS data,
(3) Some heuristics on the limiting shape of the ice in September.

It seems the Pacific side of the Arctic Basin will have a relatively high amount of ice in September.  The Atlantic side has some weak spots.  But time is running out and I think the importance of the Pacific side will outweigh the Atlantic one.

The weather in the last 2 weeks led to divergence and holes opening up on the East Siberian side of the Arctic Basin.  But I guess most of the ice in that region is still in a relatively good state.

The forecasted temperatures in the Arctic Basin are still low.  The ice in the weak regions will melt and compaction may take place, but I don't think this will suffice for the September mean extent to drop below the 2011 level.  In fact, I think it will be close to the 2010 level.

F.Tnioli

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #19 on: August 07, 2013, 11:40:43 AM »
My intuition says september minimum will be some 90%...105% of 2012's. I made this prediction yesterday elsewhere.

Interestingly, this nearly matches two answers of this poll taken together - because 90%...105% of 2012's september minimum equals 3,249...3,79 (assuming 3.61 for 2012). Since i can't vote for two answers here, though, i picked 3,25...3,5 one.

Interestingly, i am the 1st person to do so, in this poll.

Now, about why i think it'll be roughly 3,25...3,8 (apart from intuition, that is), based on my message which i made elsewhere yesterday.

...
So i now think we'll indeed see "extremely fast ice melt later in August and in September". In part, both the current halt and the incoming extreme melt (which i predict here) - are and will be real; but, in other part, it's just a quirk of reporting systems. Quirk which is significant enough to explain in a bit of detail.

I mean, if, now, some relatively large areas of, say, 30%...50% ice concentration are reported as "ice covered", and then, if just 1/3 of _really_ existing ice surfaces in such areas melt away, - then any system which reports 30%-or-higher-ice-concentrations as "ice covered" - will "suddenly" report dramatic reduction of ice cover in such areas. Math for this is simple:
 - minus-one-third to 30%...50% - equals 20%...33.3% remaining ice concentration, and then only a QUARTER of such areas will remain above 30% of sea ice concentration:
 - 33.3% - 30% = 3.33% is the part which is above 30%,
 - 33.3% - 20% = 13.3% is the whole thing,
 - so 3.33% / 13.3% = 0.25 = 25%, i.e. one quarter remains above 30% ice concentration - the other 75% "suddenly" start to be said "no ice cover".

So, in this particular example, the process of melting of 33% of initially existing (at some point) _real_ ice surface - results in the loss of 75% of _reported_ ice cover. Impressive quirk, eh? *

* again, this is not about all ice area/extent monitoring systems, but only about those which assume 30% sea ice concentration still being "ice covered", and anything less - not being "ice covered"; however, same logic applies much to most systems, as there usually still is some lower limit below which pieces of the ocean "start" to be considered ice-free - for some it's 15% ice concentration, for some 25%, for some 30%, etc.

So, relatively small _real_ further ice loss can result in massive _reported_ ice extent (area) loss.

When and why can this happen? Obviously, when Arctic has large areas which at some point are having "just slightly above minimum ice concentrations to be reported as ice-covered". As for "why", i suspect that that massive cyclone which happened in late July spred alot of ice to a larger area, thus indeed creating large areas which have much-lower-than-100%-ice-concentration areas, which for _now_ are still being reported as "ice covered", thus creating conditions for above described "quirk" of reporting systems to become seriously significant.

I also have a guess why this sort of thing didn't happen before - not at such a dramatic scale, that is. I mean such a definite and long (~11 days) _halt_ of the process of early-august ice area declining, reported by some systems, such as Cryosphere Today.

Until quite few last years (~10), Arctic had much more ice during this time of the year; and in many places - for many thousands kilometers, - ice fields were actually still in contact with land (Eurasia and North America continental shores). The land prevents sea ice from spreading out, if there are air and/or ocean currents pushing it - and massive cyclones have very powerful air currents which do just that, especially for ice fields which are already below 100% concentration (created surface water waves and pushing, "sailing" ice packs a bit). So, in the past, with more land in contact with larger perimeters of ice fields, there were more cases of shores holding  much of the ice, which occasional late-july cyclone was trying to "veer away". And in such "collision course" with lands, ice packs were opposing their own melt by getting pressed into higher ice concentrations, too.

Nowadays, with much more open water near polar shores, and large areas of open water next to them, late July / early August large-scale cyclone have much more free water to drive remaining ice fields to. And, when there is no land mass for ice packs to "stop" at, there is also no "putting ice together into close to 100% concentration" force - ice packs continue to "sail" open waters under strong cyclone's winds while still being much like "swiss cheese", i.e. having way lower than 100% ice concentration. Which, i guess, just happened (during last two weeks) on unprecedentally large scale. And to which existing systems of reporting sea ice area/extent are not exactly prepared for, it seems - the "quirk" i described above is probably not the only possible difficulty.

One might ask why this sort of _reported_ halt in early-august Arctic sea ice melting process - 10+ days of pretty much stable total sea ice area/extent, - did not happen during last few years, when there was much open water, late July, near Arctic shores. Well, i guess it was because no truly large cyclones which were pressing ice packs into large bodies of open water were developed in the Arctic at this particular time of the year - late July.

And, by the way, i believe that it's indeed late July when large-scale ice fields are already weakened much by summer melt, and can be readily separated on a large scale by cyclones, if pushed to large open water areas; but in the same time these ice fields are often still thick enough and large enough to not disappear right away under cyclonic conditions, - similar cyclone in late August would produce much more quick "result" in terms of additional and readily observable reduction of reported ice cover.
...

All the above is an opinion of an amateur (me), which may be wrong in some parts (hopefully not entirely, though! :) ). I am happy to stand corrected, if/when i'd be wrong somewhere. Please do point out any mistakes you could see, but please do bring sound, rational arguments while doing so. Thanks!


P.S. While i predict september minimum ice extent near or slightly below 2012's, i also expect this year minimum ice volume to stay significantly above 2012 september minimum in the same time. We'll see.
« Last Edit: August 07, 2013, 11:46:32 AM by F.Tnioli »
To everyone: before posting in a melting season topic, please be sure to know contents of this moderator's post: https://forum.arctic-sea-ice.net/index.php/topic,3017.msg261893.html#msg261893 . Thanks!

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #20 on: August 07, 2013, 03:54:16 PM »
NSIDC down 18k1, with my breakdown:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   11.2                   -14.0                    -3.1
               Kara Sea             Barents Sea           Greenland Sea
                    7.1                     0.8                   -10.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -0.1                     0.0                   -11.6
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    0.9                    10.8                    -9.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -18.1


BornFromTheVoid

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #21 on: August 07, 2013, 03:56:20 PM »
Just 18.1k dropped on the latest update (for the 6th), so still above the extent of the 4th.



The rolling 7 day loss has now been below the 81-10 average for 2 weeks straight.
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #22 on: August 07, 2013, 05:16:16 PM »
NSIDC have a new update out. They discuss the rapid July loss, the recent slow down, the melt ponds and a good bit on Arctic summer storms.


A month of two halves and no hole
Following rapid ice loss in the first half of July, the pace of seasonal ice retreat slowed the rest of the month partly due to the return of a stormy weather pattern over the central Arctic Ocean. The timing of melt onset for 2013 was in general unremarkable. Ice extent remains below average on the Atlantic side of the Arctic, and near average in the Beaufort and Chukchi seas, and along the Eurasian coast.

The rest is here http://nsidc.org/arcticseaicenews/2013/08/a-month-of-two-halves-and-no-hole/
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #23 on: August 07, 2013, 05:54:12 PM »
Their description of the disappearance of the N Pole 'lake' is wrong however.  It did not disappear under a thin film of ice, the stakes were immersed under several inches of standing water.  When the 'lake' disappeared the stakes were seen to be above the ice by about 0.75m, the water must have drained away.

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #24 on: August 07, 2013, 09:18:01 PM »
And they say:
"The summer storms in this region can occasionally be quite strong and there has been some discussion that, like hurricanes, strong Arctic storms should be named, perhaps drawing on the Inuit language."

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #25 on: August 08, 2013, 07:21:22 AM »
I'm going up another block to 4.25-4.50.

The slowdown during the second half of July means to me that we're running out of time to melt the ice, and we're not coming close to 2012.

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #26 on: August 08, 2013, 03:52:43 PM »
NSIDC down to 6.49500 Mm2, down -120k3

Details:
Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    7.2                   -49.9                    -8.1
               Kara Sea             Barents Sea           Greenland Sea
                  -18.5                    -1.5                    -7.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -5.1                     0.0                     6.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   10.2                   -44.5                    -8.8
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                  -120.3



Yup, it is ESS, Beaufort and Kara.

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #27 on: August 08, 2013, 03:56:00 PM »
NSIDC down to 6.49500 Mm2, down -120k3

Details:
Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    7.2                   -49.9                    -8.1
               Kara Sea             Barents Sea           Greenland Sea
                  -18.5                    -1.5                    -7.9
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -5.1                     0.0                     6.7
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   10.2                   -44.5                    -8.8
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                  -120.3



Yup, it is ESS, Beaufort and Kara.

You keep getting the updates literally seconds before me!

The 7 day loss is back above average for the first time in 2 weeks, but we're now over 1 million km2 below 2012 for the first time since the end of June.
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #28 on: August 08, 2013, 06:56:12 PM »
NSIDC down to 6.49500 Mm2, down -120k3

Yup, it is ESS, Beaufort and Kara.

Figure sharp changes were afoot looking at the Bremen extent map today.  A huge swath of ice in the Beaufort disappeared literally over night.
This space for Rent.

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #29 on: August 09, 2013, 04:11:20 PM »
NSIDC 6.44911, down 45k9

My calculation, not exact but close enough:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -8.5                   -21.0                     4.5
               Kara Sea             Barents Sea           Greenland Sea
                    0.9                     8.8                     4.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   14.4                     0.0                     2.2
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -12.9                   -28.0                   -11.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                   -46.5

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #30 on: August 10, 2013, 03:52:53 PM »
NSIDC 6.38133, down -67.8

Details:
Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    7.9                   -30.0                    -7.2
               Kara Sea             Barents Sea           Greenland Sea
                  -14.9                     9.1                   -11.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -2.1                     0.0                   -27.3
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    7.5                    -8.2                     8.2
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.6                     0.0                   -67.8

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #31 on: August 10, 2013, 03:57:03 PM »
That 67.8k drop is close to the long term average drop but slower than the last 5 years.

1.29 million km2 below 2012.
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #32 on: August 10, 2013, 05:03:39 PM »
Wouldn't the short term effect of this cyclone be a slowing of the extent loss due to divergence caused by the cyclone? Are we seeing evidence of this divergence and, if so, where?

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #33 on: August 10, 2013, 05:30:49 PM »
Wouldn't the short term effect of this cyclone be a slowing of the extent loss due to divergence caused by the cyclone? Are we seeing evidence of this divergence and, if so, where?

https://forum.arctic-sea-ice.net/index.php/topic,382.msg12052.html#msg12052

The ice edge north of Frans Josef Land (and Svalbard) is extending.

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #34 on: August 10, 2013, 05:55:48 PM »
MASIE has recorded a 194.7k drop for yesterday, with a drop of 50.7k in the ESS, 36k in Beaufort, 33.8k in the Greenland sea and 29.2k in the CAA.

Has anyone got the MASIE data from last year?
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #35 on: August 10, 2013, 08:59:39 PM »
MASIE has recorded a 194.7k drop for yesterday, with a drop of 50.7k in the ESS, 36k in Beaufort, 33.8k in the Greenland sea and 29.2k in the CAA.

Has anyone got the MASIE data from last year?

Just rename the file's extension to xlsx and open!

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #36 on: August 10, 2013, 09:03:03 PM »
Last Year total NH from MASIE

2012218    6,471,961.20
2012219    6,421,379.67
2012220    6,384,857.77
2012222    6,119,555.87
2012223    6,102,354.16
2012224    6,158,597.87
2012225    6,149,315.82
2012226    5,963,224.88
2012227    5,984,255.47
2012228    5,786,062.28
2012229    5,769,006.87
2012230    5,749,069.19



BornFromTheVoid

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #37 on: August 10, 2013, 09:20:34 PM »
MASIE has recorded a 194.7k drop for yesterday, with a drop of 50.7k in the ESS, 36k in Beaufort, 33.8k in the Greenland sea and 29.2k in the CAA.

Has anyone got the MASIE data from last year?

Just rename the file's extension to xlsx and open!

Great, cheers!

Although I know it's not really meant for year to year comparisons, it is still interesting that the CAB is lower this year than last year.
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #38 on: August 11, 2013, 03:08:42 PM »
I voted 3.25-3.5M I'm guessing that there is 750k of air left in the extent balloon. Who really cares how much open water there is among the ice? I guess people like big numbers.

Vergent

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #39 on: August 11, 2013, 03:55:22 PM »
NSIDC 6.31667 down -64k7.

My calculation is one irritating pixel aka grid cell off:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                    5.9                    -0.6                   -23.9
               Kara Sea             Barents Sea           Greenland Sea
                  -11.5                    -6.8                    -3.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -10.5                     0.0                    -6.4
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   13.6                   -13.9                    -6.1
             Bering Sea          Sea of Okhotsk            Total Extent
                   -0.6                     0.0                   -64.0


BornFromTheVoid

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #40 on: August 11, 2013, 04:10:22 PM »
Update for the week to August 10th

The current 1 day extent is 6,316,667km2, while the 5 day mean is on 6,451,478km2
 
The daily anomaly (compared to 79-11) is at -1,133,920km2, a decrease from -1,253,840km2 last week. The anomaly compared to the 07, 11 and 12 average has increased from +435,720km2 to 795,420km2 this week. We're currently 6th lowest on record, up from 5th lowest last week.
 
The average daily loss over the last 7 days was 51.9k/day, compared to the long term average of 69.0k/day, and the average of the last 5 years of 87.5k/day.

The average long term loss over the next week is 53.7k/day, with the average of the last 5 years being 67.2k/day.

The loss so far this August is the 16th largest on record, at -779,760km2. We need to average a loss of 92.3k/day for the remainder of the month to record the largest August extent drop on record.

The current extent is below the annual daily minima of 16 out of 34 previous years, and within 1 million km2 of another 12.





« Last Edit: August 18, 2013, 04:26:25 PM by BornFromTheVoid »
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Juan C. García

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #41 on: August 11, 2013, 04:56:47 PM »
I am know forecasting 4.25-4.5 million km2 on NSIDC 2013 Arctic September (NSIDC Arctic SIE Monthly Average)
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.

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #42 on: August 12, 2013, 03:59:29 PM »
NSIDC 6.20006 down -116k7

My details:
Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -0.6                   -12.2                   -18.7
               Kara Sea             Barents Sea           Greenland Sea
                    2.5                   -11.8                     8.5
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.4                     0.0                     0.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                 -115.4                    28.7                     5.1
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                  -116.6


Something odd in the CAA.

[Edit here are the area numbers:]
Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -26.4                     1.5                    -6.3
               Kara Sea             Barents Sea           Greenland Sea
                    5.5                    -2.4                     0.8
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -3.2                     0.0                    -0.8
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                  -38.1                     1.0                     0.8
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                   -67.7
« Last Edit: August 12, 2013, 04:27:11 PM by Wipneus »

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #43 on: August 12, 2013, 04:42:56 PM »
Wipneus.....

We can certainly see the divergence caused by the recent cyclone in the Beaufort, Chukchi and CAB in SIA and SIE. Should we expect the ice moving into the Beaufort and Chukchi to melt out this season? Another way of asking this: has the cyclone actually set us up for rapid drops in SIA and SIE before the melting season has ended?

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #44 on: August 12, 2013, 05:34:26 PM »
Wipneus.....

We can certainly see the divergence caused by the recent cyclone in the Beaufort, Chukchi and CAB in SIA and SIE. Should we expect the ice moving into the Beaufort and Chukchi to melt out this season? Another way of asking this: has the cyclone actually set us up for rapid drops in SIA and SIE before the melting season has ended?

Chukchi is already "virtually" ice free:


Beaufort is nearly so, and well on the way be:


I am not really sure what the cyclone did cause in all this. Much of the current state of the ice can be explained without the cyclone.

The CAB is key in what will happen in the next 5 weeks: in 2012 the CAB kept declining until the 20th of September or so.


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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #45 on: August 13, 2013, 02:38:07 PM »
I went with 4.75 to 5.0, up from the guess of "4.4" that I'd been maintaining through July.  I use a simple model that looks at the distribution of ice loss in previous years, and the confidence interval has been tightening rapidly.  That 4.4 now seems to be out of reach (alas). 

I'm a bit mind-boggled that people were still voting for numbers below 4, or even below 3.  Perhaps those votes were before this most recent cyclone, and the low numbers were assuming that it would be a replay of last year's cyclone.    But for now, it seems far more likely that 2013 will end up around 5.0 than below 4.5. 

That shouldn't be shocking; before 2007 *every* year was above 5, and there is a lot of year-to-year noise in the data. 

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #46 on: August 13, 2013, 03:55:02 PM »
At 6.23125 and uptick of +31k2

Here is my regional extent and area split:

Extent:
           Arctic Basin       East Siberian Sea              Laptev Sea
                  -11.1                   -24.2                    12.2
               Kara Sea             Barents Sea           Greenland Sea
                  -12.3                    38.2                    -5.2
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                  -25.7                     0.0                    47.9
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                   28.6                    -6.4                   -10.7
             Bering Sea          Sea of Okhotsk            Total Extent
                    0.0                     0.0                    31.2

Area:
           Arctic Basin       East Siberian Sea              Laptev Sea
                   -0.3                    11.0                     5.2
               Kara Sea             Barents Sea           Greenland Sea
                   -3.4                    10.8                     0.6
Baffin/Newfoundland Bay            St. Lawrence              Hudson Bay
                   -7.5                     0.0                    12.5
   Canadian Archipelago            Beaufort Sea             Chukchi Sea
                    5.4                     2.7                    -3.1
             Bering Sea          Sea of Okhotsk              Total Area
                    0.0                     0.0                    34.0


You can start analyse now.

OldLeatherneck

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #47 on: August 13, 2013, 10:25:14 PM »
At 6.23125 and uptick of +31k2

Here is my regional extent and area split:


Wipneus,

Can you explain why  the extent in the Barentz Sea and Hudson Bay jumped so dramatically??

THANKS
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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #48 on: August 13, 2013, 10:53:23 PM »
Especially since Barents melted out weeks ago...

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Re: NSIDC 2013 Arctic SIE September minimum: August poll
« Reply #49 on: August 14, 2013, 07:06:32 AM »
At 6.23125 and uptick of +31k2

Here is my regional extent and area split:


Wipneus,

Can you explain why  the extent in the Barentz Sea and Hudson Bay jumped so dramatically??

THANKS