Support the Arctic Sea Ice Forum and Blog

Show Posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Messages - jdallen

Pages: [1] 2 3 ... 49
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: October 10, 2017, 08:52:00 AM »
That animation is mildly encouraging.
Gonna throw some cold water at you.  The sooner the ice shows up, the sooner it locks accumulated heat in the water.

Arctic sea ice / Re: JAXA 2017 Arctic SIE September daily minimum: June poll
« on: September 24, 2017, 09:58:52 PM »
The JAXA extent minimum for 2017 was 4.47 million km2 on 9 September 2017.  So the correct bin in this poll was 4.25-4.5.

This means that 96.8 percent of the votes in this poll were too low, 2.4% were too high, and 0.8% were in the correct bin.  Moreover, the median of the votes in this poll was about 2.93 million km2, which is 1.54 million km2 too low.

Compare with previous years:

June 2013 poll:  99% of predictions were too low, 0% were too high
June 2014 poll:  98% too low, 0% too high
June 2015 poll:  73% too low, 18% too high
June 2016 poll:  91% too low, 3% too high (JAXA),  and 94% too low, 2% too high (NSIDC)

Thanks for pointing out the obvious. For 5 years in a row now the large majority of posters on this site have been wrong about the ice. This isn't random bias either, as they are always overestimating melt. It's past time for most people here to adjust for their bias and follow the data more closely.

Adjustment needed.  Truedat
Now hang on just a minute.  The June poll is absolutely not intended to be definitive, and for many of us is our best guess based on previous behavior of the system. 

For example, my guess (3.25-3.5 million) was based on the application of a statistical expectation of typical summer melt behavior going back to 1980.  What made my guess wrong was something that hasn't been predictable - peak melt season weather.

I'll also say that my later season estimates have been much closer - even dead on (IJIS extent).

There may be bias, but most of the guesswork being done *is* founded on reasonable expectations.  With the ice in its current state, as it has been since after 2007 and more so after 2012, each season is a dice roll.  If we'd had conditions like 2007 or 2012, no doubt my estimate this year would have been on the *high* side, and we all be talking about how our bias was wrong in the opposite direction.

Arctic sea ice / Re: The 2017/2018 freezing season
« on: September 23, 2017, 03:13:17 AM »
Looking at dmi forecast you can see that the pacific side is still melting a bit, it will take maybe 2-3 weeks before we see big refreezes here.
In my opinion after this year we can see, that very often the effect of open ice in september in many years like last years may have a positive effect of next years ice.
Maybe the water just cools down more if it refreeze later.
So many years with catastrophic ice and regain the next year now.
South of 80N will refreeze more slowly, possibly not refreeze for quite a while.

Not sure if the heat loss will make up for the net increase in enthalpy.

We may see a lot of imported heat from cyclonic storms pulling moisture north from tropical and mid latitutdes.

That will slow heat loss from the Arctic.

Arctic sea ice / Re: The 2017 melting season
« on: September 20, 2017, 06:01:31 AM »
We may simple by in a holding pattern.  The summer minimum in extent may be constrained by the water and air temperatures and circulation.

There could be a 'pause' (dare I use that term?!) in volume loss due to changes in global energy distribution
I think it will transfer, and that's will be what kills the pack.

I think it will take some time - possibly decades as others have suggested.

Even without a sub 1 million KM2 melt year, I think the trend is going to be very bad for life in the northern hemisphere.

I think we are starting to see the wild oscillations in climate that will by typical until the heat redistributes propotionately in the system.

It's not clear to me how the Pacific and Atlantic can both get hotter without that heat transferring to the Arctic, but assuming it can happen, the Antarctic is screwed worse than I thought.

Arctic sea ice / Re: The 2017 melting season
« on: September 18, 2017, 08:52:23 PM »
Probably my final 2017 descent to the min graph update. Probably.
I find it interesting that only 2007, 2011, 2012, 2015 and 2016 are lower, and we are in the "pack" for most of those save 2012.

In volume, we are lower, and in average ice quality, I think we have to go back to 2013 end of season to see anything approaching what we have now - but 2013 still had more thick ice than we have now.

A fascinating year so far, and one which may possibly reflect a new transitional pattern where feedbacks from increased water vapor like cloud cover and increased snowfall attenuate summer extent loss.

I think this will continue for some time, possibly even decades.  I think it will be punctuated at intervals by deeper meltouts to near or under 1M KM2 area, possibly under 1MKM2 extent, but will recover.

I think the transition to fully, seasonally "ice-free" Arctic conditions won't happen until we see water temperatures at depth in the basin rise at least a degree C.  At that point, there will be sufficient energy to continue vigorous bottom melt long enough that even the cloud and snow cover feedbacks won't reduce albedo enough to save the ice.

(Edit) A caveat to the ice's survival is tied to the refreeze rather than the melt season.  With Arctic amplification and the disruption the Hadley/Ferrell/Arctic cell circulation, winter temperatures will be crucial to the ice's survival.  If we start seeing winters which consistently follow 2015/2016 and 2016/2017 temperature pattern, the pack will be come far more vulnerable to factors which previously were marginal, such as Fram export which carries off the remaining thick MYI.  A bad refreeze leaving ice in the state it was this year in May then means that even what was a normal melt season prior to 2007 could become catastrophic.

We are very fortunate I think, that recent melt seasons have been anemic.

Arctic sea ice / Re: IJIS
« on: September 15, 2017, 07:44:55 AM »
This sucks so much!  I, like all on this forum, need ZERO ice!  Those damn denialists have to be proven wrong!  Our earth is going to go ice free and they have to pay!!
Life's hard, but we need to go on in a way or another...
Beyond the absurdity of somehow making denialists pay, I have to say I'd love nothing better than to to have them proved right... but I won't be, nor will the climate cooperate.

What we are seeing is the climate equivalent of a fugue, as we go through a period of chaotic behavior as we transition from year round ice coverage to seasonal coverage.

Arctic sea ice / Re: The 2017 melting season
« on: September 13, 2017, 07:32:06 AM »
Arctic is certainly an eye catcher. So are polar bears, although they have lost their luster as the "canary in the mine" since by all accounts their population is stable and they are not drowning or starving.
<raised eyebrow> 
You may want to defend that statement ... in a different thread.

Arctic sea ice / Re: The 2017 melting season
« on: September 06, 2017, 02:14:12 AM »
no net refreezing growth anywhere

Yes, which is starting to be harder to reconcile with observational products, areas shooting up by some 100k's in a few days and things like that.
... which I think in fact may be related to limitations of those products trying to measure what are threshold conditions in the Arctic.

They were designed to analyze the ice based on a multi-KM grid, and I submit have serious challenges acurately representing the atomized slush we see in the region currently.

I also wonder if they are able to deal accurately with increased snowfall, which is also a new feature of seasonal behavior.  As someone else said in the forums, the Arctic is no longer (or at not completely) a desert.

I think we've already seen a few years of this, with increasing destruction of ice quality starting in 2013 - which was a watershed for quality even as it was a rebound.

We have a fraction of 2012's MYI, which has been distinctly decreasing in thickness as well as area.  We are now moved state in the system behavior where the total effective ice coverage will match very closely the total annual flux in heat entering the region.  It's only by grace of the weather we haven't passed our 1 million KM2 "Ice free" state.

The feedbacks which are preventing that are going, some year, to be overwhelmed, and that sometime is getting very close.

I think Rob Dekker is on to something watching albedo and snowfall.  Unlike the pre-2007 years, I don't think the Arctic has the buffer any more which can soak up excess heat.  We've been steadily losing ground in the refreeze.  Warmer winters are going to end up what kills the Arctic, not summer heat, I think.

Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: September 03, 2017, 05:29:55 AM »
Interesting watching the pull-back from Svalbard and the Barentsz.  Perhaps Atlantic water is making itself felt again now that the thickest of the MYI in the area has melted out, and is no longer being replenished from the pack.

If we get cyclones rolling up the coast, it will be interesting to see if the edge retreats back as it did last year, even as the interior froze.

Arctic sea ice / Re: IJIS
« on: September 03, 2017, 05:23:02 AM »
There was a lot of compaction in my view due to the persisting action of an HP on beaufort sea. This is also causing a sisignificant temperature drop though. As usual in this part of the season we're probably having refreezing on the CAB and melting/compaction of peripheral ice. They will tend to offset each other as we move towards the minimum...
To add - there are large areas of thin, highly fractured ice as well, which is vulnerable to bottom melt, even as air temperatures drop.  Until they drop down to -5/10C, that can continue to happen.

Arctic sea ice / Re: The 2017 melting season
« on: August 31, 2017, 03:45:56 AM »
Would not take much for most of the ice in that image to disappear
True, but not much action seen out to day 5 in either of our ice thickness and ice boundary predictions systems, ESRL and Hycom, though note the suggestion of CAA garlic press onset in the latter which could potentially break up what little remains of the very thickest ice.

Indeed very little happened by way of trend in the 13-29 Aug 17 time frame for UH AMSR2 sea ice concentration, which mostly wobbles between dispersion, compaction, and bulk ice pack displacement.
I expect it all got thinner however.

Right now, I'm watching the eastern seaboard of North America as I think the first of what will become a regular series of tropical depressions will start sweeping NE to eventually descend on the Barentsz, taking in train massive amounts of moisture.

At some point, the remains of Harvey will emerge from the Mississippi/Ohio watershed and similarly start a more rapid northeasterly trajectory.

If the Cyclone Cannon starts up, that will push the minimum out, possibly quite a ways, as the heat they carry will slow loss to atmosphere and permit more bottom melt.

If it does not, then we may see an "early" start to the refreeze, which may still be bad news, as it will tend to trap more of this season's heat.

Regardless,  anything beyond 2nd year ice will be at historically low levels, and none of it particularly robust, even as it puts a lid on the arctic.

Arctic sea ice / Re: IJIS
« on: August 26, 2017, 02:07:11 AM »
That seems about right.  If melt picks up then 4th place is likely, otherwise 6th.

I think it is worth noting, that all of the years in question which will likely exceed 2017's melt, have occurred in the last decade.

If this were 2007, everyone would be fairly complete shock over how low extent is, much less volume or area or quality of ice.

Recent years have innured us to just how incredible these seasons are.

Arctic sea ice / Re: IJIS
« on: August 22, 2017, 05:16:42 AM »
Too less of easy ice to melt remain. I don't expect any significan decline further.
Where is the heat?
The main thing of this melting season could be the Arctic SSTs. It's worse than last year and we remember what was the 2016 fall
The effect of insolation on the ice North of 80 is pretty much done, so the end of season story will be whether or not heat loss out of the main pack will be fast enough that it can compensate for bottom melt.

As various images indicate, there is a whole lot of extent which scarcely qualifies as such.  That what is in play.

Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 18, 2017, 12:54:40 AM »
Crazy fluctuations in CAB area. Last three days: +95k, -117k and now +111k. I will say more about it in a second post. Extent is more reasonable, Greenland Sea drops most with smaller contributions on several fronts.

Update 20170816.

Extent: -82.2 (-45k vs 2016, -210k vs 2015, -697k vs 2014, -619k vs 2013, +721k vs 2012)
Area: +67.5 (+318k vs 2016, +130k vs 2015, -684k vs 2014, -416k vs 2013, +777k vs 2012)

I'm wondering if the fluctuation is a side effect of how granular the pack has become? Is it perhaps tied to the resolution limits of the sensing and computational systems? (E.g 12.5 KM grid)

Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: August 13, 2017, 10:09:38 PM »
Amazing drop in area today, mostly thanks to a regional century drop in the CAB.
Not unexpected, though, as large patches of the ice pack look very iffy.

The region was full of sub-1.75 meter ice.  The bottom melt is now catching up with that.  I expect us to see continuing major SIA losses over the next few weeks for the same reason.

Curiously, because of the highly random distribution of fractured MYI, we may not see the same impact on extent.  We could see much of the basin at very low levels of concentration.

Arctic sea ice / Re: Gulf Stream stall
« on: August 02, 2017, 12:39:36 AM »
I'm still not convinced of the "slowdown" hypothesis.

Annual flow of it into the Arctic is greater that the total winter ice volume by a factor of 20.  I have a hard time believing brine expulsion is the primary driver of that.  Even without that, even at higher temperatures, thermal contraction will provide a huge amount of energy to drive the current.


I think the ice will be more dispersed, which follows the poor quality we have seen.

Much still depends on weather.  I am keen to see what the next storms do, as badly placed, the could radically change the outcome.

Arctic sea ice / Re: IJIS
« on: July 31, 2017, 08:17:49 PM »
IJIS looks stubborn cause I was expecting bigger drops. Thin ice, probably strong storms till the end of melting season. Let's see what will happen
It's turning to slush and spreading out.  Seems to be a side effect of the weak pack we have, as the ice appears to be breaking up into smaller pieces far more readily, which reduces melt ponding.  The cloudiness then prevents sunlight from providing the coup de grace.  So far, it looks like a strong ice supporting feedback mechanism.  However, that storm... we will see how it deals with that.

Arctic sea ice / Re: The 2017 melting season
« on: July 31, 2017, 08:13:05 PM »
20 days in the Beaufort Sea. The area shown is from about 73-77N, 137-157W.

To my eye concentration increases as melt sets in, before catastrophically collapsing
Dovetailing with subgeometer.

This is the Beaufort on the 29th, a still, and shows about a quarter million KM2 of extraordinarily weak ice.  I'm doubting it will survive the coming storms/dipole, which at 72 hours out, the first one looks pretty certain.

Generally when Ice looks like that, I give it about a week before most of it is gone.

Arctic sea ice / Re: The 2017 melting season
« on: July 25, 2017, 05:37:23 PM »
Mostly clear view of the Atlantic side today and wow look at those holes opening up!
Aside from embedded MY I, most of that extent finished the freeze under 1.75M as I recall.  I expected the holes and am glad there aren't more.

More generally, I'm anticipating a reestablishment of the "Atlantic melt front" we've seen from NE Greenland running north of Svalbard and FJL, opening up a couple 100KM into the CAB proper.  I expect all the peripheral seas to melt out almost entirely.  In short, I think the end of the year will see the ice circling the wagons in the CAB at the finish, somewhere close to or slightly below 2007/2011/2016.

Arctic sea ice / Re: Latest PIOMAS update (mid July update)
« on: July 25, 2017, 05:26:00 PM »
What I notice on Wipneus's graph is the September 10 plots used to be (1980 & 90s) consistently above the 0.26m plot <snip>

Disclamer:  Wipneus's graph shows the trends.  Weather will determine the details.  :)
Very much in accord with this.  I think the key here is, unlike measuring area or extent, wip's strategy is actually a proxy for estimated heat uptake.  If I were building and placing buoys, I'd add sensors to measure full spectrum radiation.   There is a *partial proxy for *that* in the form of the voltages coming off of buoy solar arrays, but that's not complete. 

Arctic sea ice / Re: IJIS
« on: July 24, 2017, 08:03:10 AM »
What I've seen is an almost "compressive" feedback behavior, where other forces come into play slowing the melt.

I remember bbr2314 talking this fall and winter about the possible ice-age inducing effects that extra snow would have on the arctic. I dismissed his zeal around the cooling effect it would have - esp. during fall and winter. However, in hindsight the extra snow, and other related negative atmospheric feedbacks, seemed to have slowed melt in 2017 and 2016(more because of clouds, etc).

Have we entered a new phase of the arctic? Cloudy-cool-summers, Stormy-warm-winters. AKA the Wimpy Ice Phase, where sea ice extent hangs on while ice thickness plummets. How long will this phase last?

One thing seems sure to me given the decadal trend of sea ice volume loss, we are rapidly approaching the point when one ice unfriendly winter followed by an ice unfriendly summer will yield a BOE for the Arctic.

In the meantime, perhaps nature might give us a few more years to figure things out before we reach the end of the whip. In other words, ongoing BOEs, a highly-disrupted atmospheric circulation and a planetary energy budget that's running away from us at an unstoppable rate.
Snow cover is a highly volatile and vulnerable negative feedback sadly.  Unlike ice which is realtively durable vs. things like air temperature and rain, snow can vanish in a matter of hours completely changing a major system dynamic (albedo) literally overnight.  As such, it is much more at the mercy of chance, which over the last 5 years following 2012 has managed to work more in our favor.

The energy budget and total enthalpy in the system is The Thing.  In a sort of inverse Pit and the Pendulum, that heat raises the target for each swing of the annual solar "Pendulum".  Eventually, however much the Arctic manage to suck in its belly, it will not be able to avoid getting cut lethally; at least, not without some sort of stupendous intervention.

We're not going to see it coming, as our current metrics like IJIS extent can't "see" that heat, and the nature of the ice and the system are changing in ways that we can't quantify.  Right now, I think anyone making a definitive prediction of the year of the ice's disappearence is throwing darts blindfolded.  We simply don't have all of the data we need to predict that.

Arctic sea ice / Re: IJIS
« on: July 24, 2017, 07:52:32 AM »
My current working hypothesis about this can be summarized thus:  <snip>
Thus, everything points to an Arctic which very suddenly changes -- even if we cannot tell when this will happen.
There is much merit to your observation, Dharma Rupa.  The Arctic has become a very chaotic system, with the potential to tip over into a very different regime very quickly.

I think we need to be tracking other dimensions more closely - sea water heat distribution, albedo, rate of thermal transfer between water and atmosphere, water vapor, total system enthalpy among others - as I think they would give us more insight.  It would be better if we had history for all of those things, but sadly, we do not.  If wishes were horses, beggars would ride.

Arctic sea ice / Re: IJIS
« on: July 23, 2017, 07:17:16 PM »
The mistake you and others make is the assumption that this year's ice is anything like previous years.  Or that this year's climate is anything like previous years.   Or that atmospheric circulation or ocean currents and temperatures are anything like previous years.

You can crunch numbers all you want, but if circumstances in the past in no way resemble current circumstances, then it's just GIGO.

You can't treat a transforming system as if it's a static one and derive anything useful.

We have variations on this post LITERALLY EVERY YEAR.  One year they will be right, much like a stopped clock. When that year comes, don't delude yourself that you deserve credit for your foresight.
To underscore Peter's point, I've made similar assertions, presented similar tables of data, made similar dire observations about the ice, only to have it act inconsistent with my predictions.

In short, in spite of the state of the ice, in spite of previous years behavior, because of the state changes taking place in the system at this level of coverage and volume, those statistical analyses lose their predictive power.  What I've seen is an almost "compressive" feedback behavior, where other forces come into play slowing the melt.

My current working hypothesis about this can be summarized thus:  once melt retreats past about 75N over all, the system dynanimics change sharply. My thought is, that open water becomes a buffer which more efficiently and evenly redistributes heat.  I think the dynamics of phase change come into play as well, with heat which previously melted ice, taken up by evaporation, which in turn further contributes to increased albedo.  To summarize, we see increasing feedbacks from different mechanisms that don't exist or are retarded at higher levels of ice coverage.  I think they are the only reason we aren't seeing open water at 90N by early August.

Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: July 23, 2017, 01:50:16 AM »
The ice in Kara shows how fast it can disappear suddenly.
The ice generally really is following my expectations.

Arctic sea ice / Re: The 2017 melting season
« on: July 21, 2017, 09:20:20 PM »
<snip: Too many nested OT comments. Leaving your relevant notice intact. JP>

Back to topic please.  Discussion of the relative accuracy and merit of various organizations data belong elsewhere on the forums.  Ad hominem attacks belong nowhere in our discussions.

Arctic sea ice / Re: The 2017 melting season
« on: July 21, 2017, 05:05:55 PM »
I agree with 2015 and 2016, not so much with 2013, at least not on the base of a single image.

Here's a second image, showing some open holes on July 6th 2013:
2013 was terrifying. Cloudy weather and calm conditions are the only reasons we didn't have a crash that year.

Arctic sea ice / Re: The 2017 melting season
« on: July 19, 2017, 09:33:34 PM »

Conventional wisdom tells us that years with high compactness ratios generally don't break records. At some point conventional wisdom no longer applies. We don't know if that point has been reached this year. Doesn't look like it to me, but you never know (volume is still record low, according to PIOMAS).

The current weather forecast is perfect for ice retention. Conventional wisdom says that at some point this will cause hiccups in extent decrease. Greenland surface melt may show a spike though:

It is hopeful that the weather is good for retention.  OTOH, pertinent to our understanding of compactness,  what's N and E of Svalbard I think contributes significantly to that high ratio, and isn't exactly reassuring, considering the image I captured below.

I will add, that recent changes and melting out in the Barents are starting to show a return to both higher SST's, and a reassertion of the "Atlantic Front" we saw last year.  The second image shows how a combination of drift and warmer Atlantic from the south has started opening up the water north of Svalbard as we have seen frequently over the last few years.

Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: July 19, 2017, 09:17:51 PM »
Ice in about all possible NW passages turns mobile.
I also note Beaufort ice being driven south back across astonishingly warm water.  That won't be good for it.

Arctic sea ice / Re: IJIS
« on: July 17, 2017, 12:47:54 AM »
And I was looking forward to seeing video of you delivering the Pork pies to a local Mosque to feed climate change refugees.  ;D
... what?  This forum's OK with casual racism now?
I missed that.  It's not OK as far as I'm concerned <directs a level gaze at Hyperion>

Arctic sea ice / Re: The 2017 melting season
« on: July 16, 2017, 08:48:40 PM »

an understandable point of view which probably won't be totally off but the there are few things
to consider:

a) it's colder in the cab than in the barnetz

b) there is less insolation in the cab than in the barentz

c) there is less open water (wave action and energy) in the cab than in the barentz

d) there is less heat close by, be it water bound or in the air

e) the surrounding ice is more mass than further south.

Thank you for your points.

I'm aware of the differences regionally.

I'd disagree that "heat near by" really makes a signficant difference except by way of facilitating the creation of melt ponds.  Right now that's moot in my opinion.

What is relevant is ocean heat and insolation.  To a lesser degree rainfall may come into play, but still is a lower reservior of heat that the other two factors.

I will agree that intruding Atlantic water into the Barentzs provides significant heat, and that insolation is declining.  However, we have 8 weeks left in the melt season, and the lions share of that work in August will be bottom rather than top melt.

I'll add that the region I'm considering is adjacent to the Barentzs and is subject to much the same forces the Barentzs is.

On the Pacific side, the situation is actually much more dire, much is at lower latitude will be getting more insolation for longer longer.

Lastly, I think you are underestimating the potential for storms to stir up wave action inside of the CAB.  There is nothing like the contiguous stretches of ice we saw in previous years.  It is much more like 2013, that by the end did resemble a bowl of ice cubes.  The thing that saved us that year was persistent cloudiness *and* virtually stagnant airflow.  That's not been the case this year. Those gaps between blocks are measured in 10's of KM, which is far and away enough to cause 1-2M swells given even a modest 20-30KPH surface wind.  Those swells would be both very destructive to the relatively weak frangible ice we have, *and* the ability of that wind to move both water and ice around will prompt ekman pumping bringing up heat from depth far more easily than in the past.

We will need better weather than we've been getting to save the ice.

If we get a GAC as we did in 2012, I think the results this year would be far more dire.  I will be watching the coming hurricane season with intense interest.

Arctic sea ice / Re: The 2017 melting season
« on: July 16, 2017, 08:32:43 PM »
Another illustration.  See below the CAB just north of the gap between FJL and Svalbard.

Compare the ice quality here to the northern Kara sea on June 30th.

Admittedly, the Kara was under more insolation pressure, but given a month of similar weather, the CAB region shown here *will* turn into just so much soup.

Arctic sea ice / Re: The 2017 melting season
« on: July 16, 2017, 08:12:54 PM »
I think the heat is on now on the pacific side of the CAB. This doesn't look like a "mood" for me of the Bremen graph, there's too much green already.

No, this is real, Uni Hamburg AMSR2 shows it too. There's a lot of melting potential there, and given the 'piggy bank' ice in the Kara Sea, Laptev Sea and Baffin Bay, I'm expecting the series of JAXA century breaks to continue for a while longer.
I'm expecting them to become ubuquitous.

To my point, I'm going to go back to the quality of the ice.  I've got three images below.  The first two of are the NE corner of the Barentzs, a month apart - May 26 and June 26.

The last is a section of the CAB which has been previously highlighted, approximately the same area, today.

Considering the similarity between this and the May 26th Barentzs ice, I will be very surprised if much of this doesn't disappear by August 15th.

This kind of ice quality is very common across easily half of the remaining CAB extent.  Unless we get weather on a par with 2013 and 2014, I think the 2012 records are still very much in play.

The ice we have now simply is not the same as anything like previous years.  The closest would be 2013. 

We dodged a bullet then.  Unfortunately global weather circulation does not appear to be as favorable to us this year as it was then.

Arctic sea ice / Re: 2017 sea ice area and extent data
« on: July 16, 2017, 07:22:04 PM »
Very mixed picture. Large extent drops in Kara but rebounds in ESS and Chukchi. While UH AMSR2 "saw" concentration drops on the pacific side, the NSIDC ice concentration is declining on the Atlantic half of the ice pack.
Looks to me to me like lots of late FYI melting out within the pack proper, leaving behind the relict early FYI and sad bits of MYI behind.  Considering the condition of the ice I've been following in those areas, this comes as no surprise to me at all.

Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: July 16, 2017, 09:50:11 AM »
I think it is worth mentioning, most of the CAB ice which intruded into the Barentsz is now gone, and the Atlantic margin is well on its way to retreat back to the line it occupied in 2016.  In short, the heat is back on in the Barentzs.

Arctic sea ice / Re: The 2017 melting season
« on: July 14, 2017, 10:36:15 PM »
Following this as close as I did for years now. However, I'm going to enjoy a short holiday. When I'm back, I expect to see what I've been forecasting for almost two years.
MODIS 13/07 perfectly shows what Wipneus published today in the 'Extent' thread. Wrangell Island is practically cleared now. the state of the pack in that sector is horrible.
Daily Composites shows that temp anomaly in that sector was worse than '16 all May-today. The seas out there will clear in a linear fashion until the 15% border will have passed the '07 minimum within weeks.
I still expect this will become a new minimum season.
Even though the Atlantic doesn't seem to co-operate...
Expanding on what Werther has said, as an illustration of what I (and I think he) expect to see starting to develop across the basin.

Two weeks in the Kara Sea.

<click to animate>

Arctic sea ice / Re: The 2017 melting season
« on: July 14, 2017, 05:33:37 PM »
Anyways a lot of the easy ice of past few days melted in the past 3 so now it may take more work to melt the next sections. ...
Normally, that would be true. But we are going through this "soup" season here, as i call it. All bets are off.

Based on the fragmented state of the ice, and how much late, thin FYI is woven through the pack, the melt season is playing out much as I'd imagined.

What remains to be seen is if weather and the break we got from additional snow cover will rescue the pack  from a new low.

I think it possible we might find ourselves in a unique place in September. I think it possible we may still see a new low in area, but may not have one in extent.

Arctic sea ice / Re: The 2017 melting season
« on: July 13, 2017, 07:03:21 AM »
And one more:  broader view of the western Beaufort to the eastern ESS.

Arctic sea ice / Re: The 2017 melting season
« on: July 13, 2017, 07:01:42 AM »
A few less clouds today on the Terra-Modis images for the 12th. Nth pole at bottom right corner. Franz-Josef land at top left. Still veil of fog or cloud over most. gives that wavey mottled look. A few spots where there is none and the ocean between the floes stands out nice and dark though.
Its like many other areas.  Large swaths - upwards of 3 million KM2 easily - look to be in a state where they have 5-10 days before they vanish.  Some samples attached.  Pretty much what we see, is isolated early FYI or surviving MYI surrounded by a melange of rapidly disintegrating thin late FYI.

A couple solid whacks and the arctic will be indistinguishable from a bowl of ice cubes.
Successively, from the last couple of days:
Foxe Basin
Western Kara
CAB NE of the ESS

No wonder poll results are always skewed so low.
It's common practice in various self sampling tests to drop the top 5 and bottom 5 percent of scores before generating an average.  This especially makes sense when you know some responses *will* be deliberately skewed.

Another approach would be to look at the median rather than the average.

My two cents on sampling these estimates to arrive at an aggregate.


Arctic sea ice / Re: Arctic Image of the Day
« on: June 28, 2017, 02:30:16 AM »
I am dreaming of the North Pole and Central Arctic Basin full of round ice floes with no square shapes to be seen anymore. Today's thin sea ice in the CAB is no longer capable to survive intact when sea ice floes toss each other (due to winds and ocean currents), turning them all ....
Deli, you may have accidentally found the single largest surviving block of ice in the CAB...

Arctic sea ice / Re: The 2017 melting season
« on: June 27, 2017, 09:26:09 PM »

The ice pack isn’t very thick and badly fragmented.

The main difference is extent on the Atlantic side. But, over there, more fragmentation than ever. Under the right conditions, a lot of ice will be pushed South and melt, even though the Atlantic may not be that warm now.

There’s a dipole in the make. It could be the beginning of the event. Hold on.

To your point, Werther, while we have considerably more extent and area in the Barentsz, Greenland and Kara seas, that extent is mostly slash and extremely vulnerable.  I think the three images (first two using bands 7-2-1, last visible) I selected over the last three days illustrate that.  I tried to select periods with lower cloud cover.

The visible light shot of Svalbard/Fram very much highlight your point.  As the pack breaks out of the CAB into the strait, the infill around what appear to be MYI blocks rapidly disappears, and ice which is backed up against the islands themselves shows signs of attack from both above and below.

(Edit/post script)
I think it quite possible we could see 2017 reach lowest SIA but not quite reach lowest SIE.

As posted elsewhere, all hinges on July's weather now.  Unfortunately with the forecast Beaufort high and dipole, it's not starting out well for the ice.

Arctic sea ice / Re: The 2017 melting season
« on: June 27, 2017, 07:52:48 AM »
<snippage> If this set-up remains dominant into July, this year is top 3 material. At the very least.
Definitively not the weather we were hoping for, Neven.

Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: June 26, 2017, 07:39:46 PM »
Even Jaxa shows the torching Beaufort.
Direct sun plus bottom heat plus warm 2M temps could translate to 10 CM/day coming off some areas of ice.  When do we expect that high to show up? How long will it hand around!?

Arctic sea ice / Re: The 2017 melting season
« on: June 24, 2017, 08:09:06 AM »
Lot of clouds, but look at this ice mobility between North Pole and Kara Sea. Image: Worldview, Jun 23.
This, is a nightmare; peak of installation, major storm disrupting the pack and simultaneously pulling heat up from depth.

We arent even into July.

Arctic sea ice / Re: IJIS
« on: June 20, 2017, 05:44:55 AM »
Based on temperatures leveling out and the fact that the ice around the edges was thinner than usual and has melted out fast, there is a good chance the rate of melting will begin to decrease somewhat and ice extent will maintain 4th place for a while and then climb perhaps to 6-8th place. Just a hunch. If I knew how to project the future I'd be rich trading stocks!

For your "hunch" to come to fruition, the rate of extent decrease, which has been the second fastest on record for this time of year so far this month, would have to magically slow to by far the slowest on record.

Not. Going. To. Happen.

Friendly advice: stay away from the stock market. :)
I'm trying to understand this and, apparently, failing.

The most recent 2017 value for IJIS is 9982791.  FTB didn't specify an exact time frame, so let's say this is over the next two weeks:

* If the ice follows the pattern of 2003, 2005, 2008, 2009, 2011 or 2016 it would climb to 6th place.

* If the ice follows the pattern of 2015 it would reach 8th place

* If the ice follows the pattern of 2004 it would reach 9th place

So melt rates from 8 of the past 14 years would bring FTB's "hunch" to fruition. 

Maybe I've badly miscalculated something, or maybe I misunderstood the claim.  But Jim Pettit's comment makes no sense to me.
The problem lies in an assumption of equivalency of the ice across all those years.  Further it assumes equivaleny of other conditions - total enthalpy, volume. Weather among others - so using purely statistical methods of predicition are no more reliable for this years minimum than last year's price movement would reliably predict where your favorite NYSE ticker will be in two months. Don't bet on it.

Arctic sea ice / Re: The 2017 melting season
« on: June 16, 2017, 07:21:38 PM »
Happening now over Laptev Sea up to: 50km/h winds, 2.5C temps, and quite a bit of precipitable water (26.500 kg/m2) in the air column - could be raining as we speak?
A number of us had been looking ahead to this moment for several days.  If 2M temps are in the 2-3C range, it is very probably rain falling. The 850mb temps are similar or slightly higher, so I think parts of the Laptev are currently getting a shower.

Arctic sea ice / Re: The 2017 melting season
« on: June 16, 2017, 12:20:42 AM »
Please, don't get too excited about things beyond 6 days out. This is a forum, not a news paper.

And I believe that a moniker like GAC is given après le fait. Besides, it would be the third in 5 years. It's almost becoming normal.

For now, we have the dipole and a medium cyclone forecast for the next couple of days. It will be interesting to see what that does.
The weather 48-96 hours out could be significant with that storm in a tight loop on the north of the Laptev.  2M temperatures could be significant as well, with Siberian temps in the mid 20s and higher swept north,  which will reduce snow cover on land and potentially on ice.

Ice in the Kara may get swept back over open water, and more CAB ice shoved towards the exit along the Barentsz.

Yes, it will be interesting enough already, I expect, without looking further.

Arctic sea ice / Re: The 2017 melting season
« on: June 15, 2017, 07:43:07 AM »
Updated this again as the openings are getting bigger each day. Worldview has been so cloudy.
CLICK IMAGE Zoom         12th-14th

I would be fascinated to see an explanation for this, as the current visible images from Worldview really don't show any hint of a hole.  Here's a shot of the region; the "hole" *should* be in the lower right quadrant of the image.

Lots of very messed up ice, but no hole.

Pages: [1] 2 3 ... 49