IJIS

[bbr2314]

Hello magnamentis maybe I can help explain. First of all you get some reactions because of the noise that "bbr" was making for the last several weeks, now people are tired of all the alarms and react harshly even if you are not to blame.
About the cliff, maybe it is a question of definition. I think most people see "cliff" as a sharp sustained drop in extent beyond the normal for the period. So if 2016 was ahead of all years by a huge margin but now it is not, it means that 2016 dropped less than others and calling it a cliff is wrong by the common definition (as I understand it).
If you define cliff as a few century drops over a few days that just keep the chart right with the charts of the other years, you might confuse people that expect cliff as defined above.

2016's area is now below 2012's (as it has been most of the year) so if by "alarms" you mean "accurate observations" I accept your apology.

[Buddy]

With all due respect people have been yelling 'cliff' for more than a month now. You might be right but I think there is too much crying wolf in here.

Certainly possible.  I don't think so...but we will certainly find out over the next 9 weeks or so....

[Bill Fothergill]

...
2016's area is now below 2012's
...

Hopefully I have managed to transcribe the following values correctly: if not, I humbly apologise in advance.

At the time of writing, the latest shadow-CT NH area figure kindly provided by Wipneus was dated 2016.5260, and had a value of 5.716 million sq kms. By way of comparison, using the Cryosphere Today database as the source, the equivalent 2012.5260 value was 5.598 million sq kms.

Therefore, again at the time of writing, the latest available CT NH area value is just over 100k sq kms in excess of the equivalent day's value in 2012.

Going back 10 days however, the 2016 area was just over 400k in excess of the 2012 equivalent, so the gap has narrowed significantly. As both my crystal balls are suffering from age-related degradation, I don't know how things will pan out come September.

[Neven]

2016's area is now below 2012's (as it has been most of the year) so if by "alarms" you mean "accurate observations" I accept your apology.

This is the IJIS (or JAXA) sea ice extent thread, and at the time of writing 2012 is 135K lower than 2016, with 2011 being 287K lower. I'm still expecting this year's trend line to more or less follow 2014 in the coming 10-14 days, but maybe the century breaks will keep coming in.

[Tensor]

 

that's interesting, i referred to exactly his point and i say 2 cliffs happened,

snip...

 meaning behind it.

You know, I don't see any of that, nor anything that can honestly be called a cliff in the data Epsen's been posting.  Since this is the IJIS thread, I'll be more than happy to apologize, as soon as you point out the double century drop in the IJIS or even a high century drop, in the last month to six weeks.

 

EDIT...BTW he did and it's all good, why should others chime in on behalf of someone who can easily elaborate himself ...?

Why shouldn't others chime in? Do you object to others chiming in, in an open forum?  After all, you were allowed to chime in here, in an IJIS extent thread, with area data which had no relevance to the data here.  Yet you object others chiming in asking where the evidence for a cliff is?  Sounds like an interesting ethical conundrum, no? 

[Michael Hauber]

In 2012 the cliff came in early August, hastened by the GAC.  However I believe 2012 would have had a cliff without the GAC, as the weak area from Beaufort to Laptev separated the ESS ice, opening up two melt fronts.  It would have been delayed until mid August.  There was that modelling study discussed several times on this forum that estimated that without GAC the minimum would have been only a little higher.  Surface melt this year is weaker, so that may delay thing as well.  So mid to late August for a cliff?  Except by then melt rates are slowing down.  It may not be so much of a cliff, but a case of faster melting continuing for longer than normal, similar to 2008.

I think we'd need some relatively extreme weather to see any cliff this July.

[Espen]

IJIS:

7,757,371 km²（July 13, 2016）

[Tigertown]

All you cliff jumpers out there, careful what you wish for. A buck fifty drop today!

[Juan C. García]

All you cliff jumpers out there, careful what you wish for. A buck fifty drop today!

Date          Extent       Drop
11-jul-16   8,047,131   
12-jul-16   7,908,219   138,912
13-jul-16   7,757,371   150,848

 

[Tigertown]

I didn't get it wrong that time  my old buddy. I was just rounding it off.

[Juan C. García]

I didn't get it wrong that time  my old buddy. I was just rounding it off.

My surprise is because it is a drop of almost 290,000 km2 in just two days.

[Michael Hauber]

Flash melt - two substantial areas in Chukchi and Beaufort have totally dissapeared off the sensors, presumably as measured concentration fell below whatever threshold they currently use.  Both areas are under heavy cloud, so MODIS doesn't shed light on what is actually happening.  The ice in both areas was certainly weak, but it wouldn't surprise me to see areas of this ice reappear if/when the current cloud clears.  Weather charts suggest conditions are warm and windy under the cloud, so there is undoubtedly some substantial real loss of ice going on as well as whatever sensor variation is happening.

[Tigertown]

        I know it Juan.  Possibly because of the peripheral oceans that are heating up so much. HYCOM (I know,nobody likes it)  shows a continuing increase in warm waters especially on the Siberian side. I believe it after seeing how the area of warm water has grown around the New Siberian Islands.

[oren]

According to the regional charts, the areas where the chart took a dive in the last few days are Chukchi (at last), CAA and of course Hudson which is expected for this date.
The only area still not participating is the Laptev.

[phonon]

"Date          Extent       Drop
11-jul-16   8,047,131   
12-jul-16   7,908,219   138,912
13-jul-16   7,757,371   150,848"

What is the link to these data? Thanks.

[epiphyte]

I think we'd need some relatively extreme weather to see any cliff this July.

For my own part I have no definite opinion on that - but on the flip side I think that at this point it might equally take some extreme weather to prevent a cliff before the end of August.

Widespread, unusually high ice granularity & mobility, the absence of snow cover (even with similar volumes of precip to that which killed the CAB melt in 2013), continuously shifting, but always mixing, wind patterns, persistent, relatively high temps, instantly melting exported ice.

...All of these seem to me to indicate that the numbers (e.g. 25km grid extent/area), heuristics (e.g. melt-pond fraction based on sheet ice with snow cover) and broad-brush thermodynamic models (e.g. PIOMAS) which adequately served to track melt progress in the past may be of dubious value in the endgame.

OTOH. IJIS extent is still within spitting-distance of the record levels at which it has been coming down all year - so maybe even that number is indicative of less tepidity than those expecting daily visual confirmation of inscrutable processes might expect.

[Rob Dekker]

In 2012 the cliff came in early August, hastened by the GAC.  However I believe 2012 would have had a cliff without the GAC, as the weak area from Beaufort to Laptev separated the ESS ice, opening up two melt fronts.  It would have been delayed until mid August.  There was that modelling study discussed several times on this forum that estimated that without GAC the minimum would have been only a little higher.

Michael, do you have any info about that "modelling study" that estimated that without the GAC the minimum in 2012 would have been only a little higher ?
Because that is exactly what my projections show

Just a little bit lower than the prediction.

[Michael Hauber]

Michael, do you have any info about that "modelling study" that estimated that without the GAC the minimum in 2012 would have been only a little higher ?
Because that is exactly what my projections show

Just a little bit lower than the prediction.

Found it:  here 

[Jim Hunt]

What is the link to these data? Thanks.

You can read them off the graph, or alternatively download all the data from:

https://ads.nipr.ac.jp/vishop.ver1/data/graph/plot_extent_n_v2.csv

[Neven]

for the new ads vishop, it seems to be located here - https://ads.nipr.ac.jp/vishop/graph/Sea_Ice_Extent_N_v2_L.png

Cats or anyone else, do you also know what the direct link to the CSV file is (also for the ASIG)? I tried a few combinations, but nothing worked.

Edit: found it here.

Edit2: Thanks, Jim. Your link even has .ver1 just behind the vishop.

[Buddy]

And for our next trick....we'll make it disappear:

Date          Extent       Drop
11-jul-16   8,047,131   
12-jul-16   7,908,219   138,912
13-jul-16   7,757,371   150,848

[AmbiValent]

It's HYCOM. So it would be wise to prepare for it to happen then, but also prepare for it not to happen then.

[Buddy]

Here's July 2012 for comparison.  At some point....much of the ice, as someone else noted, just goes "poof".  How much remains this year....is all up to the vagaries of the short term weather over the next 8+ weeks.  Pretty stark difference.....

[Jim Hunt]

Here's July 2012 for comparison.

We've been through all this recently Buddy. Comparing ACNFS v03.5 (2012) with v04.2 (2016) is apples versus oranges.

[Buddy]

We've been through all this recently Buddy. Comparing ACNFS v03.5 (2012) with v04.2 (2016) is apples versus oranges.

Thanks....I guess I was "out that week".

But having said that....I can understand that the versions changed, and algorithms changed...and I can understand that it would be more than just "fine tuning".  But I also can't help but think this is CERTAINLY closer than "apples and oranges."

There is a large area of 1 meter thick ice (making the assumption that the new version is right) that is "vulnerable"....and with more "work", will go poof.

If you've already addressed this....no need to beat this horse any further...I certainly trust your word (and I can look back through some of the threads to see what those specific differences are).

As an aside, if you look at ACTUAL PICTURES of the central CAB ice in 2012...vs now......those pictures paint the same stark difference in ice.





 

[Jim Hunt]

As an aside, if you look at ACTUAL PICTURES of the central CAB ice in 2012...vs now......those pictures paint the same stark difference in ice.

We've been through all that too.

making the assumption that the new version is right

What if it isn't right though? Here's one actual picture of the central CAB ice:

[bbr2314]

As an aside, if you look at ACTUAL PICTURES of the central CAB ice in 2012...vs now......those pictures paint the same stark difference in ice.

We've been through all that too.

making the assumption that the new version is right

What if it isn't right though? Here's one actual picture of the central CAB ice:

Here's another actual picture of central CAB ice:

[bbr2314]

Despite some faults I think both ARC and GLB are onto the truth. Satellite grabs over the past few days show failure on all three fronts (ATL, PAC, and the Russian side especially), but the Russian side doesn't present as a solid front (nor does the Beaufort melt), and the leads keep getting absorbed into the slush of the main pack (which is why the 'slush' keeps expanding, and why most of the CAB has now evolved into this state). The only solid regions of ice are those bordering the steaming ATL waters as well as some remnants north of the CAA (no coincidence the latter was chosen as 'evidence').

Realistically most of the ice in this photo will be gone by 8/1. 2012 was not a fractured slurpie, the Central Pack still had much more integrity and wasn't completely fractured.

I also have a problem with people saying that 2012's GAC was a Black Swan when it very well may have been directly caused by the area losses that year. It would actually make sense that as area declines to near 0, warm airmasses ascending from the continents and the oceans increasingly begin to meet with one another (Arctic Amplification!) as heat is exchanged across the North Pole instead of being defused (except for what goes into and out of Greenland at that point).

So if 2012 was any kind of indicator, I think we are likely to see at least one GAC this year. We've already seen several lows into the 970s, which is borderline Category 2-hurricane pressure.

[ktonine]

We've been through all this recently Buddy. Comparing ACNFS v03.5 (2012) with v04.2 (2016) is apples versus oranges.

Has anyone actually posted any evidence that it's an apples to oranges comparison?  Is it apples to oranges?  Is it apples to apples? Is it oranges to apples? I.e., does this version yield a warmer, cooler, or equal temperature arctic?

I see an assumption based -- apparently -- on different version numbers, but no qualification, much less quantification of any real differences.  Per the update info available, 2012 (ver 3.5) data used NOGAPS atmospheric forcing and now ACNFS is using NAVGEM 1.3 forcing.  The really suspect comparison would be with 2015's ver 4.0 where erroneous SST data was assimilated; making 2015 look warmer than the model would have with correct data.

Even considering the comparisons that were made before NAVGEM was incorporated it isn't easy to say what the actual effects are.  There are clearly differences, but those mostly calibrated out to provide a standardized product:

Initial comparisons of NOGAPS and NAVGEM 1.1 surface fields indicate large differences in some variables such that GOFS/ACNFS cannot simply switch to NAVGEM 1.1 with the expectation that the ocean/ice model response will be unchanged. Therefore, FNMOC continues to run NOGAPS until 31 August 2013 but will provide only to the Naval Oceanographic Office (NAVOCEANO) that output required for their ocean/ice models. In the interim, NRL – Stennis Space Center (SSC) will perform the needed calibrations to assure the ocean/ice model response will be consistent across the NOGAPS decommission time boundary. The calibration work and subsequent hindcasts/forecasts are the subject of this report.

and we can also read:

Five-day ice concentration forecasts from NAVGEM 1.1-forced ACNFS and NOGAPS-forced ACNFS are shown in Figure 11 and both are performing very similarly. Thus, ice forecasts appear to be less sensitive to the magnitude of the heat flux offset and/or its frequency of application. This result holds throughout both the summer/spring melt and fall/winter growth seasons.

This information would indicate that is pretty much an apples to apples comparison (with the exception of 2015).  Differences between NAVGEM versions may be a different story.

[Jim Hunt]

Has anyone actually posted any evidence that it's an apples to oranges comparison?

Perhaps we might pursue the matter on a thread at least approximately designed for the purpose, rather than cluttering up the IJIS thread with yet more off topic debates?

[Espen]

IJIS:

7,611,399 km²（July 14, 2016）

[Juan C. García]

Date           Extent         Drop
11-jul-16   8,047,131   
12-jul-16   7,908,219   138,912
13-jul-16   7,757,371   150,848
14-jul-16   7,611,399   145,972
      
Total on 3 days:      435,732

Wow!!! 

[Juan C. García]

Second place!
Above 2011 but under all the other years, including 2012.

[Rob Dekker]

Michael, do you have any info about that "modelling study" that estimated that without the GAC the minimum in 2012 would have been only a little higher ?
Because that is exactly what my projections show

Just a little bit lower than the prediction.

Found it:  here

Thanks Michael. That study by Zhang and Lindsay (the PIOMAS guys) states :

The simulated Arctic sea ice extent minimum in 2012 is reduced by the cyclone but only by 0.15 × 106 km2 (4.4%). Thus, without the storm, 2012 would still have produced a record minimum.

The interesting thing is that this difference (150 k km^2) that the GAC caused in 2012, is very close to the difference in my projection for 2012 (which was 200 k km^2 off) and thus that I agree with them that 2012 would still have produced a record, even without the GAC.

[Bill Fothergill]

With the 7.611 million sq kms figure posted for July 14, the IJIS/ADS NH Sea Ice Extent 12 month rolling average has now crept just below 9.98 million sq kms.

Putting this into some perspective, and briefly setting aside the 2012 melt out, the lowest such value hitherto recorded was 10.015 million sq kms; this being for the 12 month period ending on 17th November 2011. (That value was matched by the 22nd June this year.)

Unsurprisingly, the events of 2012 put this rather transient record to the sword. Allied to the relatively low values recorded early in 2013, by the 15th of May that year, the current all-time-low rolling 12 month value of 9.915 million sq kms was duly clocked up.

I know that there are conflicting views as to the likely trajectory for the remainder of this current melt season, and I personally think that it will be weather that has the final say. However,  here is a naive projection: should the gap between 2015 and 2016 remain roughly as it stands at the time of writing (~ 600k sq kms) then, by about August 23, there will be a new record for the lowest rolling 12 months.

Gulp!

[Jim Pettit]

Date           Extent         Drop
11-jul-16   8,047,131   
12-jul-16   7,908,219   138,912
13-jul-16   7,757,371   150,848
14-jul-16   7,611,399   145,972
      
Total on 3 days:      435,732

Wow!!! 

Not bad; that's the first and only instance of back-to-back-to-back SIE century drops this year. And FWIW, last year's mid-July IJIS "cliff" began similarly:

15-jul-15   8,209,972   
16-jul-15   8,054,919   155,053
17-jul-15   7,920,964   134,225
18-jul-15   7,767,001   153,693
      
Total on 3 days:      442,971

[magnamentis]

Date           Extent         Drop
11-jul-16   8,047,131   
12-jul-16   7,908,219   138,912
13-jul-16   7,757,371   150,848
14-jul-16   7,611,399   145,972
      
Total on 3 days:      435,732

Wow!!! 

and predicting that one gets bashed, thanks for providing the numbers, perhaps even the last doubter are waking up, especially and again considering the conditions in which the reminder o the ice is in. on spot after another disappears now almost over night and it's becomes visible even to the narrow "focused" eye.

[Buddy]

Not bad; that's the first and only instance of back-to-back-to-back SIE century drops this year. And FWIW, last year's mid-July IJIS "cliff" began similarly:

15-jul-15   8,209,972   
16-jul-15   8,054,919   155,053
17-jul-15   7,920,964   134,225
18-jul-15   7,767,001   153,693
     
Total on 3 days:      442,971

Yes....and 4 days earlier than last year.  Going to be an interesting ride...especially the next 6 weeks.  Slushy ice....warm water....and warm air.  Not a good combo for Mr. Ice Sheet.

Again....I expect a record low come September.  It is only by how much...  If you "add" a few days on to the front of the melt season AND add a few days on the end of the melt season....interesting things can happen.  But the "meat" of the season is on NOW...and the next 6 weeks will be a ride....

[Jim Pettit]

and predicting that one gets bashed, thanks for providing the numbers, perhaps even the last doubter are waking up, especially and again considering the conditions in which the reminder o the ice is in. on spot after another disappears now almost over night and it's becomes visible even to the narrow "focused" eye.

2015 saw a ten-day extent drop of 1.2 million km2 from July 16-25. And while July-to-date has caught up a bit over the past several days, it's still several hundred thousand square kilometers behind 2007, 2011, and 2013 so far as month-to-date losses are concerned, and just about dead even with 2009 and 2012. With those figures in mind, overzealous types may find themselves in September wishing they'd tempered themselves a bit more in July...

This graph shows total IJIS extent loss for June and July-to-date. As one can see, 2016 continues to lag far behind most of the rest of the pack.

Again....I expect a record low come September.  It is only by how much...  If you "add" a few days on to the front of the melt season AND add a few days on the end of the melt season....interesting things can happen.  But the "meat" of the season is on NOW...and the next 6 weeks will be a ride....

Early August 2012 saw that unprecedented--and unrepeated since--GAC-powered 7-day drop of just under a million km2. The long-term average over that one-week span has been less than half that. So it's going to take something extraordinary to put 2016 below 2012.

[icy voyeur]

and predicting that one gets bashed,  ...

Nope, predicting a series of double century drops, again, after prior extreme predictions repeatedly fail, that gets one "bashed".  Sometimes I don't think you're reading the same forum.

[magnamentis]

and predicting that one gets bashed,  ...

Nope, predicting a series of double century drops, again, after prior extreme predictions repeatedly fail, that gets one "bashed".  Sometimes I don't think you're reading the same forum.

you tempt me to provide 20 links to 20 of my recent posts on the matter but don't wanna take this further, i will make use of the nice ignore feature to keep this civil.

[Sleepy]

The best way to keep things civil is to stay on topic.
July 15: -97182.

[icy voyeur]

and predicting that one gets bashed,  ...

Nope, predicting a series of double century drops, again, after prior extreme predictions repeatedly fail, that gets one "bashed".  Sometimes I don't think you're reading the same forum.

you tempt me to provide 20 links to 20 of my recent posts on the matter but don't wanna take this further, i will make use of the nice ignore feature to keep this civil.

Then I guess you won't see that my note that my comment was not an attack on you, which was somewhat obvious, by virtue of my not attacking you but attacking a behavior that was explicitly specified. I'm limited to English.

Looks to me like we might indeed reach a new record, especially given the headstart of the CAB over prior years. I fear weather that might invoke Fram export on top of steady regional melting. Seems to me there remain significant vulnerabilities but wild uncertainties in what the next 3 weeks will bring.

[Sleepy]

We roughly need to see today's numbers on average for three weeks, to reach 2012.

[Michael Hauber]

The ADS looks somewhat unstable at the moment.  There has been flash melting of areas in ESS, Beaufort and Hudson.  Today's changes show much of the ESS ice that flash melted re-appearing, and another smaller area of ice in the Beaufort disappearing.  The disappearing ice is again under the same area of heavy cloud that the ESS ice disappeared under.

The amount of ice that reappeared in ESS it seems hard to reconcile a 90k+ drop, so perhaps some/much of this ice is still below the extent threshold. 

[Espen]

IJIS:

7,514,217 km²（July 15, 2016）

[oren]

Must say 2016 is keeping up nicely in the race, despite melting momentum or lack thereof. Lack of winter power, highly mobile ice and the hot Atlantic are doing a decent job so far.

[magnamentis]

Must say 2016 is keeping up nicely in the race, despite melting momentum or lack thereof. Lack of winter power, highly mobile ice and the hot Atlantic are doing a decent job so far.

exactly that and it's one of the years with the least diversions from the main trend and certainly that on the low general level it is. i still stick to my earlier opinion that considering the condition of the rest we shall end second without GAC and first by far with GAC in August or early september, that's weather and can simply not be predicted.

further in every poll, where it's well documented, the majority is gathering in the forecast region i und others were in from day one, obviously developing an eye for this new field of interest.

[Nick_Naylor]

You may be wanting to invest in my new invention 

[Michael Hauber]

further in every poll, where it's well documented, the majority is gathering in the forecast region i und others were in from day one, obviously developing an eye for this new field of interest.

I've been at 3.75-4 in every ADS poll since May, although I haven't been documenting my vote in comments.  But I see from comments that your vote has increased every month after starting at 2.75-3 in May.

edit: but before I get someone to build that machine for me, I do have to say that in 2012 I thought there was little chance that 2007 record would be broken (melt season to slow starting on Pacific side), and I've been expecting the 2007 record to be broken by a bit every year since.  I should be right on that point sooner or later....