NSIDC 2013 Arctic SIE September minimum: July poll

[Neven]

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.

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 July 2nd:



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 August 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.

[Neven]

I went up one bin compared to last month to 'between 3.75 and 4.0', because I'm just conservative by nature. I don't think last year's record will be broken, but 2013 should be able to go lower than 2007. I think this year's trend line will be a lot closer to those of previous years in a week or two.

[Peter Ellis]

Don't remember exactly what I put last time, but the intended prediction is unchanged - between 2012 and 1007, likely closer to 2007.

[Neven]

Peter, if you go to the June poll for NSIDC SIE and look at the results, your vote should be in bold.

I will open a new CT SIA poll tomorrow or the day after that, as data is trailing extent by a day or two, and I want to use the July poll from my spreadsheet as info.

[Peter Ellis]

Aha - thanks.  I'm up one bin from previous, then, and just one bin above you.

[Jim Hunt]

Have you read the NSIDC July update yet Neven?

Ice cover this spring was very thin in parts of the Arctic, suggesting that large areas may soon start melting out completely. Much depends on whether the atmospheric circulation pattern seen in June persists through July.

Would you care to reconsider?  I'm still sitting on the fence! As Gavin Schmidt puts it:

With Arctic sea ice melt season just getting underway, keep track of observations here!

[BornFromTheVoid]

3.5-3.75.

I think we'll be in and around last years low. July is catch-up time.

[Neven]

Have you read the NSIDC July update yet Neven?

Would you care to reconsider?  I'm still sitting on the fence!

I read the NSIDC analysis, and even though I planned to be bolder this year, I'm just always playing it safe. Can't help myself. 

But I - and everyone here - can still change my vote in the coming two weeks. I want to see the PIOMAS update, and if things go as fast as I think they could, I might move one bin down again. Perhaps even two, although that would mean last year's record will be broken. And I still think that's going to be very difficult to top.

---

Lodger, I think the question is clear enough as it is, or else I would have explicitly said it would be for daily minimum, but then I wouldn't have put September in the question, because duh, the daily minimum is in September. Furthermore have I used all the tags there are (bold, italics, underline) in the text below the poll to make clear that there's a difference between area and extent, and between daily and monthly minimum.

If people are too lazy to make an effort, I'm not going to spoon feed them. If this isn't enough, I don't know what is.

[werther]

I just voted 3.25 – 3.5. I’m still within my range 3.28 – 4. But when pressed now, Ill go for the lower bound.
I understand why blogfriends like FI Rob Dekker come up with 4.38. But the state of the ice in the part that matters is worse than this time ’12 (*).

In a season, characterized by weather turbulence, I regard the hazard for a Nemesis cyclone to be high. Any wild jet stream branch could spawn one through July and August. A bit like our tropical weather colleagues over at Masters Wunderground. You know all the signs flare red, although the Atlantic “looks quiet now” (**).

(*) as I posted on the 'sea ice conditions'-thread, I've been comparing some MODIS tiles yesterday.
(**) the red hurricane flares: warm GOM, warm MDA (the CapeVerdian Atlantic), persistent steering, elongated Azores High

[Wipneus]

Re. the NSIDC update yesterday.

NSIDC has updated ALL June (and no other month) Arctic SIE data even in their "Final" data set, starting in 1979.

Curious.


BTW. my vote is 3.6 unchanged.

[wanderer]

3.0 - 3.25 million km2, as last month

[OldLeatherneck]

I'm going up a click to 3 - 3.25.

The fact that the middle of the CAB seems to be one slushy mess indicates that there is a great deal of vulnerable ice waiting to melt........rapidly!

[Richard Rathbone]

I was 3.75-4 last month. I'm waiting on PIOMAS before reconsidering, I don't see anything from area/extent data in the last 3 weeks to warrant a change. I'm expecting PIOMAS to show less melt than June 2012 but to be in the ballpark of 2007-2011 June melts. If it isn't I'll shift whichever way PIOMAS indicates, but otherwise I'll stick.

[werther]

About PIOMASS…
Roughly calculating the regions/areas through what FI HYCOM shows as thickness, it wouln’t surprise me if PIOMASS still shows about 700 km3 plus compared to last year.  The wildcard is Beaufort, and Kara in a lesser way. But the CAB may be surprising? My calc gives about 9300 km3 now…

[Chuck Yokota]

3.00 to 3.25
I moved up a couple of bins from last month, but I'm still expecting a record-breaking melt.

[Tor Bejnar]

I've moved up a couple of bins, and am guessing 3.6 M km^2 for NSIDC 'average' September Arctic sea ice extent.  I'm guessing ice rubble (I do prefer the term "mélange" as used in geology, as natural ice is ‘just’ a monomineralic rock) will melt like crazy in the weeks to come, but will disperse a lot too, resulting in new area and volume records, and possibly a new extent record (by a hair).

[johnm33]

As the current outlier best I say why. First the ice[CAB especially] looks like a wet concrete mix with lightweight aggregate, more like those huge pumice fields that occasionally show up in the worlds oceans than the great slabs we're used to. My guess is that it's at about -1.5C, too cold to melt , too warm to freeze. With the PAC being centered over the pole the winds surrounding it accelerated the ice relative to the earths rotation driving it south. As a rough guess the area loss times ten gives the volume moved south, where it compacted the periphery, but assuming only a third of that volume would be sucked in; diverting Atlantic waters polewards, introducing warmer waters below. Once induced the flow goes past to circle the pole and the energy center of the storm followed, also the Atlantic water has an excess of kinetic energy to shed [at 80N 180 mph at 87N 54mph earths rotational speed] that is expressed in turbulence stirring up the bottom of the wet mix. So with the added turbulence and heat gained below and constant wave motion above we have 2M? ice that's essentially fluid prone to melting and totally at the mercy of the currents and winds. Cyclone or anti cyclone it goes out of Fram.
With the high temps in the surrounding continents the reinforced periphery, which has consequentially fallen behind other years in terms of melt, is being inundated by black, peat laden, freshwater from rivers in full flood. If the winds drive the ice towards land it'll meet this water and melt, if blowing from the south it adds to the flow through Fram.
The loss of the Russian station indicates that even the thick ice is fractured and weak, even more so the speed of the icebreakers through it. It's only a matter of luck/ weather whether that breaks up and shifts or stays put. With the extremes almost everywhere else and so much energy surrounding the arctic it'd be surprising not to have storms trash it.
The north pacific is growing very warm and with every tide more of that is introduced through Bering. I expect that energy to accumulate near Banks island [it already is] and provide the impetus for the melt out between there and Fram.
We may have 3.8 left by the start of September but I expect that to be in rapid transition towards zero with in situ melt of the remaining ambiguous mush. We have a transformed fluid arctic ocean with a skin of virtual ice. 

[BornFromTheVoid]

I got in contact with the NSIDC and the changes to the June daily extent values.
I was informed that they had adjusted their June ocean climatology mask to help filter out erroneous data near the coasts and weather effects.
I was given a link to this page to help further explain things http://nsidc.org/data/docs/noaa/g02135_seaice_index/index.html#acquisition_proc

[Richard Rathbone]

With PIOMAS figures now out, and in the ballpark I was expecting, maybe a fraction more June melt than I thought there would be, but not enough to move my projection from 3.75-4.

[BornFromTheVoid]

A drop of 226k on the latest update, which makes it 1.5 million km2 lost over the last 10 days.

[icebgone]

While extent has dropped rapidly in the last few days that pace will slow down significantly once Hudson and Baffin are gone.  Beaufort is going to be delayed and may not all melt out.  I expect part of ES to survive also.  The CAB is holding its own.  That makes a total of 4.03-4.08 for Sept. average.  The intrusion of a cyclone would change everything.  I do not yet see one on the 10 day.  After that insolation starts to decline rapidly.

[Bob Wallace]

I certainly wouldn't be that the Beaufort won't melt out.  It's started melting and it has plenty of time left.

Check this year vs. 2012.



And take a look at this year's CAB.  That area of ice jumbles shows up.  That suggests that a big hole could melt out close to the pole and drop CAB volume considerably.

If you got through the Arctic region by region all one sees is that some regions took longer to get started but have plenty of time to get to zero. 

The Greenland Sea is melting out which means it's going to easier for winds to push CAB ice into waiting warm water there.  All the area past the Fram is going to be a killing field.

[wili]

Good points, BW.

As your charts show, pretty much everything outside of the Central Arctic Basin is doomed.

And, as you say, we have something which didn't happen in the past going on there--the possibility/probability of the CAB melting from the middle this year, as well as from the sides.

Add to that the broken-up, slushy nature of much of that ice, and it looks to me as if we are just a few weeks of sunny weather away from new record lows.

But then the Arctic is full of surprises...

[Bob Wallace]

Wipneus's charts.  And a fine set of charts, they are.

Best way I've seen to do a year to year comparison for regions.

[BornFromTheVoid]

A drop of 179k today, compared to the 81-10 average of 59k and the average of the last 5 years of 118k.



If we maintain the melt rate of the last 15 days (about 130k/day) up to mid month (15th), then we'll be 3rd lowest on record and just 62k off 2012...
The 81-10 average melt rate from now to the 15th is 84.3k/day, and the average of the last 5 years is 95.6k/day.

[wili]

Great graph and stats, BFTV.

It looks to me as if we might be able to maintain something like that rate of melt or better, looking at the thin, (relatively) low latitude ice that seems poised to melt out quickly right now, and the high pressures and high temps forecast for much of the region over the next couple weeks.

[BornFromTheVoid]

Cheers wili.

Just a 15k loss today

I was looking at the maximum 7 day losses during the summer in previous year and found that there have been 7 years where over 1 million km2 has been lost in a week, they are 1991, 2005, 2007, 2009, 2011, 2012 and 2013.

Here's a table with those years, number of 1 week losses >1 million km2, the maximum 1 week loss and the day of the year of the end of that maximum week


Unless we get a melt of under 49k on tomorrows update, we'll equal the number of 1 million km2 melt weeks set by 2007.
The 3 three lowest 1 week maximum losses were in 1980, 1982 and 1996, all just under 700k.

There has been a change in the variance of the day of the year in which the maximum losses occur too, which seemed to shift towards the end of the 90s.
From 1979-1997 the date of the max loss occurred between days 184 and 217 (July 2nd and August 4th) with a standard deviation of 10 days. From 1998-2012, it changed to between day 173 and day 222 (June 21st and August 9th) with a standard deviation of 18 days, essentially widening the time of year capable of producing maximum melt rates by over 2 weeks.


I think this just further demonstrates how fragile the ice has become. 2012 demonstrated this by being first year to have two periods with melt rates of over 1 million/week. One in the second week of June and one in the second week of August, both records for the earliest and latest 1 million/week losses.

[Neven]

Very interesting (and intelligible) stuff, BornFromTheVoid. And original too, although someone probably has already done this before (but I haven't seen it, or else forgotten about it). Please, keep us/me up-to-date, and I will probably blog about it in a couple of weeks when the period of maximum melt rates is behind us.

Of course, I won't mind if you turn it into a guest blog. 

[BornFromTheVoid]

Very interesting (and intelligible) stuff, BornFromTheVoid. And original too, although someone probably has already done this before (but I haven't seen it, or else forgotten about it). Please, keep us/me up-to-date, and I will probably blog about it in a couple of weeks when the period of maximum melt rates is behind us.

Of course, I won't mind if you turn it into a guest blog. 

Cheers Neven.

I'll have plenty of free time during the rest of the summer, so perhaps I'll put something together over the next few weeks

[Sourabh]

Cheers wili.

"Just a 15k loss today"

BFV,

Correct me if I am mistaken, but today's loss (July 5th down to 9.55 from 9.71 million km2) is about 150k on NSIDC. Are you referring to something else?

[BornFromTheVoid]

Cheers wili.

"Just a 15k loss today"

BFV,

Correct me if I am mistaken, but today's loss (July 5th down to 9.55 from 9.71 million km2) is about 150k on NSIDC. Are you referring to something else?

Hi

I get the daily extent data from here ftp://sidads.colorado.edu/DATASETS/NOAA/G02135/north/daily/data/NH_seaice_extent_nrt.csv

Which shows a change, from the 4th to the 5th, of 9.35443 to 9.33907, or 15.36k

I think you're referring to the 5 day mean, which the NSIDC use on their graphs

[Nightvid Cole]

I was expecting a serious crash, but HYCOM is still showing cold SST ' s even in the area where the ice is really broken up, and for it to remain that way through at least the 13th.

Not knowing what to think, I put in 3.0 - 3.25 . Maybe HYCOM doesn't account for the higher transmissivity of the broken-up ice and the 'interstitial slush'?

[jdallen]

I suspect *all* the models are suffering from serious heartburn right now. The ice is not following anyone's script.

[BornFromTheVoid]

Another small loss on today's update, just 61.8k, but enough for 2013 to equal 2007 for the most 7-day 1 million km2 losses.
I suspect another day or 2 of small losses is possible before the -ve AO and the associated ridging and heat begins a rapid melt of the ESS, Laptev and Chukchi seas, with compaction of the eastern central Arctic, spurs another period of high extent losses by mid week.

[BornFromTheVoid]

Update for the week to July 6th

The current 1 day extent is 9,277,230km2,  while the 5 day mean is on 9,452,782km2
 
The daily anomaly (compared to 79-11) is at -1,035,820km2, an increase from -646,640km2 last week.  We're currently 6th lowest on record, compared to 8th lowest last week.
 
The average daily loss over the last 7 days was 146.0k/day, compared to the long term average of 97.2k/day, and the average of the last 5 years of 103.2k/day.

The average long term loss over the next week is 83.0k/day, with the average of the last 5 years being 97.6k/day.

[Phil.]

I think this just further demonstrates how fragile the ice has become. 2012 demonstrated this by being first year to have two periods with melt rates of over 1 million/week. One in the second week of June and one in the second week of August, both records for the earliest and latest 1 million/week losses.

The table seems to contradict this since 2006 & 2007 show multiple weeks of >1 million/week, am I misunderstanding something?

[BornFromTheVoid]

Another day, and the large losses have returned, this time of 186.2k. This is enough to beat 2007 for the most >1 million/week (1M/W) losses, with 2013 now having 7.

The table seems to contradict this since 2006 & 2007 show multiple weeks of >1 million/week, am I misunderstanding something?

Hi Phil. The table doesn't show any for 2006?
It's a little difficult to explain, but I'll give it a try. All the multiple 1M/W drops, that occurred before 2012, had been consecutive 7 day periods in each year. For example, 2007, each of the 6 1M/W periods occurred on the weeks ending July 2nd to July 7th, so it was just one strong melt period. 2012 was the first to have 2 distinct melt periods with rates of 1M/W, in June and in August.
Hope that makes sense?

[Sourabh]

Another day, and the large losses have returned, this time of 186.2k. This is enough to beat 2007 for the most >1 million/week (1M/W) losses, with 2012 now have 7.

BFV,

Is that a typo? Did you mean "with 2013 now have 7"? Because in the table, it shows 2012 had four weeks of losses> 1M/W

[BornFromTheVoid]

Another day, and the large losses have returned, this time of 186.2k. This is enough to beat 2007 for the most >1 million/week (1M/W) losses, with 2012 now have 7.

BFV,

Is that a typo? Did you mean "with 2013 now have 7"? Because in the table, it shows 2012 had four weeks of losses> 1M/W

You're right. I've fixed it now, cheers!

[Phil.]

Another day, and the large losses have returned, this time of 186.2k. This is enough to beat 2007 for the most >1 million/week (1M/W) losses, with 2013 now having 7.

The table seems to contradict this since 2006 & 2007 show multiple weeks of >1 million/week, am I misunderstanding something?

Hi Phil. The table doesn't show any for 2006?

Sorry I misread the table, that would be 1991.

It's a little difficult to explain, but I'll give it a try. All the multiple 1M/W drops, that occurred before 2012, had been consecutive 7 day periods in each year. For example, 2007, each of the 6 1M/W periods occurred on the weeks ending July 2nd to July 7th, so it was just one strong melt period. 2012 was the first to have 2 distinct melt periods with rates of 1M/W, in June and in August.
Hope that makes sense?

Yes it does, so by a week you meant any sequence of 7 days, rather than a calendar week.
Are the 7 periods this year consecutive?

[BornFromTheVoid]

Another day, and the large losses have returned, this time of 186.2k. This is enough to beat 2007 for the most >1 million/week (1M/W) losses, with 2013 now having 7.

The table seems to contradict this since 2006 & 2007 show multiple weeks of >1 million/week, am I misunderstanding something?

Hi Phil. The table doesn't show any for 2006?

Sorry I misread the table, that would be 1991.

It's a little difficult to explain, but I'll give it a try. All the multiple 1M/W drops, that occurred before 2012, had been consecutive 7 day periods in each year. For example, 2007, each of the 6 1M/W periods occurred on the weeks ending July 2nd to July 7th, so it was just one strong melt period. 2012 was the first to have 2 distinct melt periods with rates of 1M/W, in June and in August.
Hope that makes sense?

Yes it does, so by a week you meant any sequence of 7 days, rather than a calendar week.
Are the 7 periods this year consecutive?

I interchanged "7 days" with "week", I should probably pick one and stick with it, but the former seemed awkward and the latter not clear enough!
This year they have all been consecutive, so you're correct on both counts.

The run will end tomorrow, unless we see a drop of well over 300k! I suspect that the next shot at recording more will be around mid month, when the large losses courtesy of the warmth and -ve AO should be in full swing

[BornFromTheVoid]

A loss of 96k today, which is above the long term average and the average of the last 5 years, but below the average of 2007,11 and 12.

[BornFromTheVoid]

A drop of 150.7k today, above the long term average, the 5 year average and the average of '07, 11 and 12.



7 day sea ice loss from June 1st to August 31t

[Tor Bejnar]

BFTV,
I'm beginning to really appreciate your 7-Day Sea Ice Loss graph.  We can see how 2012 had an exceptional 10 days or so (of ice loss) in June and another exceptional 10 days or so in August.  Given the slow start of the 2013 melt season, this year will need many exceptional loss days (in addition to the 10 or so recent ones) to catch up to 2012. 

[Bob Wallace]

Most of the 2012/2013 difference is in the Beaufort and Kara.  Those are more likely to melt out by the end of the season than not.  Both are headed down with time left to reach ~zero.

https://sites.google.com/site/arctischepinguin/home/amsr2/grf/amsr2-extent-regional.png

The next few days could show a lot of Beaufort melt.

If you look at the Arctic, region by region, you see that some regions melted a bit faster or are melting a bit faster this year than last.

Whether 2013 catches 2013 is likely a CAB issue.  And right now there's little difference between the two and reports of the CAB ice being highly fractured.

[BornFromTheVoid]

It doesn't look too likely that we'll see a significant slowdown in the melt over the next week.

Looking back over the previous July melts, the largest monthly extent drop on record is 3,374,720km2 in 2009. To beat 2009, we require an average daily loss of 94.1k for the remainder of the month, which seems achievable.
The lowest July extent drop, 2,075,790km2, occurred in 1999. To beat that, we only need to drop 35.1k/day.

Up to this point in the month, the extent loss is the largest on record at just over 1.3 million km2

[BornFromTheVoid]

Just a 54k loss on today's update, below all the averages mentioned previously. It takes the 7 day loss (747,510km2) down to the lowest recorded since the week ending June 27th (711,710km2).

[BornFromTheVoid]

Another 54k loss today.
I suspect that losses will begin increasing from now on as the current conditions begin dropping certain more areas below 15% concentration, especially around the Chukchi and ESS.

[BornFromTheVoid]

A massive drop today of 240.9k, making up for the previous two small drops.

We're now below the average of the last 5 years, and 4th lowest on record.

[BornFromTheVoid]

Update for the week to July 13th

The current 1 day extent is 8,389,280km2,  while the 5 day mean is on 8,648,404km2
 
The daily anomaly (compared to 79-11) is at -1,342,190km2, an increase from -1,035,820km2 last week.  We're currently 5th lowest on record, compared to 6th lowest last week.
 
The average daily loss over the last 7 days was 126.8k/day, compared to the long term average of 83.0k/day, and the average of the last 5 years of 97.6k/day.

The average long term loss over the next week is 88.3k/day, with the average of the last 5 years being 89.6k/day.

The extent drop so far in July is the 2nd largest on record at 1,657,940km2, second to 2007 (1,751,920km2).
An average daily loss of 95.4k/day is needed for the remainder of the month to record largest July extent on record.





EDIT: Cheers for pointing out the mistakes Vergent!