Author Topic: NSIDC 2013 Arctic SIE September minimum: June poll (Read 25560 times)

Neven · « **on:** June 06, 2013, 06:42:59 PM »

THIS POLL WILL RUN FOR TWO WEEKS (until June 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.

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 June 5th:

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.

I will open a new thread for the 2013 NSIDC SIE minimum July poll once this month is done. Keep voting. It'll be interesting to see if there are shifts in voting patterns as the melting season progresses.

BornFromTheVoid · « **Reply #1 on:** June 07, 2013, 05:06:34 PM »

Tor Bejnar · « **Reply #2 on:** June 07, 2013, 09:08:03 PM »

I'm less pessimistic on this parameter than I was a month ago – one notch upwards is still guessing for a record low value: 3.0-3.25.

Neven · « **Reply #3 on:** June 07, 2013, 09:08:57 PM »

Thanks for that graph, BFTV, much better than the big one. Help me out next month too, please. I only have IJIS and CT spreadsheets.

BornFromTheVoid · « **Reply #4 on:** June 07, 2013, 09:58:59 PM »

Quote from: Neven on June 07, 2013, 09:08:57 PM

Thanks for that graph, BFTV, much better than the big one. Help me out next month too, please. I only have IJIS and CT spreadsheets.

Sure Neven, no problem. I might need a reminder closer to the time though.

BornFromTheVoid · « **Reply #5 on:** June 08, 2013, 03:56:38 PM »

A daily drop of 75,260km2 on the NSIDC extent yesterday. Larger than the long term average drop for the time of year, but less than the average of the last 5 years.

BornFromTheVoid · « **Reply #6 on:** June 11, 2013, 04:21:43 PM »

Here's how things look up to June 10th

Vergent · « **Reply #7 on:** June 12, 2013, 02:55:34 AM »

SIE is a really poor measure. Almost 12M looks like a lot of ice relative to recent years. But CT SIA is 9.7M with -anomaly increasing. There is over 2.0M openwater in the extent. And where that 2M is is really bad.

Over the next week HYCOM is showing that patch in the CAB losing 0.5m of thickness and a 10% drop in concentration. At that rate, it will be open water by the end of June. There is relative warm water at depths from 25-50m down to 500m. Being further warmed by insolation, this water will begin to convect to the surface. This convection will be a multi-terawatt source of energy to melt ice.

I'm going with 0.5-0.75Mkm^2 with a 30% probability. I hope I'm wrong. I hope some weather comes along and blows the ice back into the CAB, but this big extent is not good news. Not with the open water "air" in the extent "balloon" being in the CAB.

Vergent

frankendoodle · « **Reply #8 on:** June 12, 2013, 11:11:31 PM »

I'm going on record with my prediction for September while it's still early June. I think this year will be our first "virtually" ice free September. I voted 1-1.25 million km2. This is due to the incredible amount of divergence all over the arctic ocean caused by that goddanm cyclone that is into it's 3rd week.
It's the difference between letting an ice cube melt in a glass of water out in the sun; and smashing the cube with a hammer, tossing the pieces back in the glass, swirling it around for a few minutes, then letting it melt in the sun.

Pmt111500 · « **Reply #9 on:** June 16, 2013, 01:47:29 PM »

voted, but really really uncertain. now there's an unseasonal low. then september might come with an unseasonal high with high convergence of the remaining muck of ice and my guess is completely shattered like the cyclone's done to the eurasian side of arctic ice. will there be much rain from it later on and many other questions. The stall in the cliff is I guess a temporary one, but who knows (still expecting at least a couple weeks with +1M losses). Did not do any calculations besides estimating the CT SIA average for sept, multiplying by 1,17 (for the 15% limit) and guessing the CAPIE. Had I done this properly with stats it'd still be there at about Del Rio/Klazes' values, I guess.

Steven · « **Reply #10 on:** June 16, 2013, 09:37:31 PM »

There is a strange discrepancy between the polls for SIE and SIA. The poll for extent makes a more aggressive prediction than the one for area. The medians are about 15% and 10% below the 2012 values respectively.

Isn't that contrary to the intuition that the ice is more fragmented, which should affect area more than extent?

It could of course be an artefact of the bin structure - but it seems consistent in all polls so far.

Neven · « **Reply #11 on:** June 16, 2013, 10:12:09 PM »

Maybe some people don't realize the NSIDC poll is for September average and not daily minimum? I keep stressing that, but it remains confusing.

James Lovejoy · « **Reply #12 on:** June 19, 2013, 01:31:40 AM »

I went with 3.75 to 4.00. Pretty much pure guess added to the fact that the artic has almost a million kM2 more extent than last year.

I expect that to narrow some, but not enough to match last year.

Tor Bejnar · « **Reply #13 on:** June 19, 2013, 05:07:54 PM »

My calculation of a weighted average of guesses to date in this poll is 3.14. Looks like a round number to me.

frankendoodle · « **Reply #14 on:** June 19, 2013, 06:18:03 PM »

As I mentioned on the SIA June poll, we have a bit of a disconnect. Lots of posts on how this will not be a record breaking season yet 3/4 of the votes on this poll are for a tying/record breaking 2013 September.
I have a feeling most of us expecting the June cliff to happen soon and rooting for a record season don't want egg on our faces. So its a silent majority if you please.

TerryM · « **Reply #15 on:** June 19, 2013, 07:43:39 PM »

By September we're going to have learned a lot about how important early melt is to Arctic sea ice. If early melt and lowered albedo are the big players we're due for a rebound of sorts from the 2012 season. If FYI, bottom melt from Ekman pumping and a thicker mixing layer are dominant we could yet see another record.
Either way we're going to gain some understanding of how the dynamics are playing out.
I had thought that this year would be a continuation of 2012 with early melt leading to another record smashing September, but something changed. The stratospheric warming event or the fracturing of sea ice or the persistent low near the pole may have released enough heat or blocked enough insolation to give us a glimpse at Gompertz's tail.

Terry

BornFromTheVoid · « **Reply #16 on:** June 24, 2013, 04:02:31 PM »

Here's the situation to June 23rd

BornFromTheVoid · « **Reply #17 on:** June 25, 2013, 04:15:24 PM »

A drop of 139k on todays update, making it 266k over the last 2 days. The 7 day mean daily loss is at the highest rate for the month and the 2nd highest of the melt season (current highest is between April 24th and May 1st)

BornFromTheVoid · « **Reply #18 on:** June 27, 2013, 04:28:04 PM »

A century break of 145.8k on NSIDC today, making it 495.5k over the last 4 days, and 614.6k over the last 7 days.

The MASIE extent has had the biggest drop of the melt season so far for day 177, 284k, and 480k over the last 2 days.

BornFromTheVoid · « **Reply #19 on:** June 28, 2013, 03:58:26 PM »

Another large drop, 145.8k for the second day. That's a loss of 641k in the last 5 days and brings us back under 2009, and to 9th lowest for the time of year.

ChrisReynolds · « **Reply #20 on:** June 30, 2013, 01:11:59 AM »

Just got an email from NSIDC, others have probably got it.

Quote

Dear colleague,

NOAA@NSIDC plans to change the baseline climatological period for the Sea Ice Index and the Arctic Sea Ice News and Analysis (ASINA) from 22 years (1979-2000, inclusive) to 30 years (1981-2010, inclusive) this July. A 30-year period typically defines a climatology or climate normal and is the standard used by organizations like the World Meteorological Organization (WMO) and NOAA. Thirty years is deemed sufficiently long enough to average out most interannual variability but short enough so that longer-term climate trends are not obscured.

These maxims about climate normals come from the world of weather and climate. Sea ice responds to climate forcing differently, and the assumptions behind the use of 30-year normals for meteorology may not hold true for sea ice, particularly in light of the rapid decrease and repeated record low minimum extents in the Arctic during the past decade. However, NOAA@NSIDC thinks that it is important to move to a longer baseline and to match the 1981-2010 period used by NOAA data centers.

Monthly and daily ice extent and area data values will not change, but data and image products that are based on the mean or median will change. For example, the trend plots will have a different scale, and the value of the slope, expressed as change in percent per decade, will change, because this value is relative to the mean period.

The monthly and daily extent images will have the same extent although the position of the median extent lines will change. The concentration anomaly and trend images will also change.

In July, we will provide more information to help users put these changes into the larger context of changing climate and changing ice. You will be able to find the data and information about the changes on the Sea Ice Index website: http://nsidc.org/data/seaice_index/

If you have questions, please contact NSIDC's User Services Office at nsidc@nsidc.org.

Best regards,

NSIDC User Services

Tor Bejnar · « **Reply #21 on:** June 30, 2013, 02:59:37 AM »

This (or some of it) was on their http://nsidc.org/arcticseaicenews/ website on June 18.

BornFromTheVoid · « **Reply #22 on:** June 30, 2013, 04:55:24 PM »

8th lowest on record with the NSIDC now, after a close to average 80.9k drop on the latest update. The past week has seen the 3rd highest weekly June loss for an individual year, dropping 890,940km2. The only two other years to beat 2013, are 2012 and 1999, that dropped, at their peak, 1,097,100km2 and 941,100km2 in a week, respectively.

It will be tough to keep up though. 2007 dropped 1.246 million km2 over the next 7 days, 2009 dropped 846k, 2011 dropped 879k and 2012 dropped 787k.

Gray-Wolf · « **Reply #23 on:** July 01, 2013, 12:29:53 PM »

I wish we could be more sure that we wouldn't match those drops BFTV?

Looking at 'werthers' efforts on comparing the Hycom data with images from the sats has me very concerned that there is an awful lot of ice that is poised for melt with very little energy needed to accomplish it?

We may be teetering on the edge of a late, yet significant 'cliff' whilst most other years were approaching the end of theirs? Should this prove true then the current '8th' will alter rapidly over the next month?

BornFromTheVoid · « **Reply #24 on:** July 01, 2013, 05:03:14 PM »

Quote from: Gray-Wolf on July 01, 2013, 12:29:53 PM

I wish we could be more sure that we wouldn't match those drops BFTV?

Looking at 'werthers' efforts on comparing the Hycom data with images from the sats has me very concerned that there is an awful lot of ice that is poised for melt with very little energy needed to accomplish it?

We may be teetering on the edge of a late, yet significant 'cliff' whilst most other years were approaching the end of theirs? Should this prove true then the current '8th' will alter rapidly over the next month?

With the latest drop of 146.1k, we're now 6th lowest on record.

No signs of the bottom of the extent cliff yet.

JackTaylor · « **Reply #25 on:** July 01, 2013, 05:21:29 PM »

BFTV,

Thanks for the chart. It magnifies great.

jdallen · « **Reply #26 on:** July 01, 2013, 07:23:00 PM »

Quote from: BornFromTheVoid on July 01, 2013, 05:03:14 PM

With the latest drop of 146.1k, we're now 6th lowest on record.

No signs of the bottom of the extent cliff yet.

I have a hunch. Is there a correlation between the decline in melt rate, and how close the SIA got to that years starting extent of MYI? Makes sense intuitively. I wonder what the proportion of MYI to FYI looks like over time, and if that might expose the bottom of the annual 'cliffs'?

BornFromTheVoid · « **Reply #27 on:** July 01, 2013, 07:32:07 PM »

There is probably something to that jdallen, but it might only be part of the story, considering how much less MYI we have this year, but how much shorter the June SIA cliff was than 2012.

There must be an algorithm change or something with the NSIDC from June 30th to July 1st, as the average drop (79-12) is a massive 221k, with the last 5 years averaging 288k. If we drop 229k or more this year, we'll have our first >1 million km2 melt week.

dbostrom · « **Reply #28 on:** July 01, 2013, 08:26:30 PM »

It seems as though many if not all of the various outfits measuring extent have shown a sudden change in slope in the past few days.

I'm a naif on how these assessments are created. Is it possible that observation conditions have recently improved such that the true state of the ice is more accurately visible now?

jdallen · « **Reply #29 on:** July 01, 2013, 09:12:49 PM »

Quote from: BornFromTheVoid on July 01, 2013, 07:32:07 PM

... but it might only be part of the story, considering how much less MYI we have this year, but how much shorter the June SIA cliff was than 2012.

No doubt; we've never seen anything quite like this year, and many of the feedback mechanisms that might have supported my hunch may either be overwhelmed or flat broken. I'll have to find some data and tinker.

BornFromTheVoid · « **Reply #30 on:** July 02, 2013, 04:11:29 PM »

Odd... seems the NSIDC have just revised all of the June daily data downward by an average of 54k. So that the average of the daily extents for the month has gone from 12th lowest (11,412,700km2) to 5th lowest (10,940,680km2).

Anyway, the drop from June 30th to July 1st was a whopping 385,470km2!!! Making the drop over the last week a huge 1,146,240km2.

This takes us to just over 600k off 2012.

Neven · « **Reply #31 on:** July 02, 2013, 04:12:57 PM »

Didn't the NSIDC switch to a new baseline?

BornFromTheVoid · « **Reply #32 on:** July 02, 2013, 04:20:56 PM »

I thought that would only change the anomalies, not the actual daily data? None of the other months were affected, just June 1-30...

wanderer · « **Reply #33 on:** July 02, 2013, 05:48:51 PM »

Quote from: BornFromTheVoid on July 02, 2013, 04:20:56 PM

I thought that would only change the anomalies, not the actual daily data? None of the other months were affected, just June 1-30...

For the first time, their Extent map seems about right to me (Even tough I don't think there is any sea ice in Northern Europe):
http://nsidc.org/data/seaice_index/images/daily_images/N_daily_extent_hires.png

Is there an archieve to these NSIDC maps? I would swear that less than a week ago there were many 100% ice-free regions that didn't show up as ice-free in the NSIDC maps!

BornFromTheVoid · « **Reply #34 on:** July 02, 2013, 06:12:56 PM »

Quote from: wanderer on July 02, 2013, 05:48:51 PM

For the first time, their Extent map seems about right to me (Even tough I don't think there is any sea ice in Northern Europe):
http://nsidc.org/data/seaice_index/images/daily_images/N_daily_extent_hires.png

Is there an archieve to these NSIDC maps? I would swear that less than a week ago there were many 100% ice-free regions that didn't show up as ice-free in the NSIDC maps!

The daily maps aren't archived unfortunately
http://nsidc.org/data/docs/noaa/g02135_seaice_index/#daily_extent_image

Just waiting for a WUWT scandal piece on the NSIDC now

ChrisReynolds · « **Reply #35 on:** July 02, 2013, 07:45:15 PM »

Quote from: BornFromTheVoid on July 02, 2013, 04:20:56 PM

I thought that would only change the anomalies, not the actual daily data? None of the other months were affected, just June 1-30...

You're right, it does only affect anomalies. As I don't follow extent I can't help further sorry.

Neven · « **Reply #36 on:** July 03, 2013, 11:26:26 AM »

Please continue the discussion wrt NSIDC SIE here. And don't to forget to vote again on the new July poll.

News:

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What will the NSIDC 2013 Arctic SIE September minimum be?

Author Topic: NSIDC 2013 Arctic SIE September minimum: June poll (Read 25560 times)

Pmt111500