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Messages - marcel_g

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Arctic sea ice / Re: The 2019 melting season
« on: September 20, 2019, 05:41:21 AM »
Though it may seem off topic, it is not.

We are, as sark notes, beginning the decades long transition to a new atmospheric circulation. We have seen aspects of this developing for the last 20 years. We will see more as the years pass.

From now on, this is on topic for each melt year.

This year it appears to have played a small role as the jet streams and circulation destabilize. Those disruptions will grow.


Arctic sea ice / Re: The 2019 melting season
« on: September 17, 2019, 07:14:03 PM »
It is interesting to note that there is a pattern to the very bad years of 2007, 2012, 2016, and 2019.

The first "bad" year was 2007. It took five years for 2012 to happen. It took four years for 2016 to happen. It took three years for 2019 to happen.

Perhaps it is nonsense, but that would put 4M KM^2 minimum as "normal" come 2021 (two years after 2019, and then we are down to one year separating these instances, i.e. it becomes each and every year), with each year thereafter likely to achieve a max under 2019, 2016, and 2007.

It should also be noted the last minimum above 5M KM^2 looks to be 2009. That is potentially about 11 years between the last minimum above 5M KM^2 and the last minimum above 4M KM^2 (using the step-trend above, that year would be 2020, or it may have already occurred).

We cannot say whether the remaining decline will follow on the same gradual continuum. Below 4M KM^2, the area / volume discrepancy inherently favors massive drops in area relative to volume as 0 is approached. I would think that there will not be another 11 years between the last 4M KM^2 min and the last 3M KM^2 min.

Does that mean we are approaching an asymptote at 4 M?
Maybe temporarily but I think the volume decline means it will not hold. Maybe it is a situation of once the asymptote is breached twice consecutively it cannot recover and spirals to near 0. Until it happens two years in a row, or rather until now, there has been sufficient momentum for temporary recoveries. As we can see in the year over year charts that momentum has been fading.

I suspect the total insolation above 80°N (from observation) is too little to melt the ice that forms on a yearly basis. The ice will have to be thinner, so less FDD days or more export. That equates to warmer and wetter weather for 9 months of the year. That or some good big storms to mix the ice with the warmer water below the halocline or in the adjoining seas during the summer.

The area within 80°N is 3883031 km2 (please someone correct that math if I'm wrong!) so perhaps that is where we will asymptote, give or take a little due to land masses causing local patterns. That may persist until we build up enough imbalance between the polar and equatorial temperatures to drive additional heat into the Arctic in the form of big warm storms.


Arctic sea ice / Re: The 2019 melting season
« on: September 16, 2019, 11:50:44 PM »
Over on the ASIB, I've just posted the late(st) PIOMAS update, and I just wanted to share the final half here, because it's how I view this melting season. Normally, I don't like it when people post long texts, but I'm the exception to that rule, of course.  ;)

Last month, I wrote at the end of the PIOMAS update:

From what I've seen on the Arctic Sea Ice Forum, written by commenters I've known for years and highly respect, my gut feeling says this year won't be able to break the 2012 records.

But for weeks now, I've been thinking of those prophetic words uttered by Peter Wadhams, back in 2007: 'In the end, it will just melt away quite suddenly.' I don't think all of it will melt away quite suddenly in coming weeks, but maybe more than one would expect just looking at the data.

This year is a great test that will tell us a lot about the importance of melting momentum.

To be honest, I expected a clearer melting momentum signal during this final phase of the melting season. Melting momentum took off slower than years like 2012 and 2016, but when it did take off, it was fireworks (see June 2019, one hell of a month). David Schröder's melt pond fraction maps, the SMOS pixel chart, the compactness charts, the Albedo-Warming Potential graphs, the snow cover graphs, more and more they were pointing to a massive build-up of melting momentum. On top of that, PIOMAS was showing that this year was very competitive volume-wise, and for five months in a row, 2019 was in the top 3 when it came to temperature records (August coming in lowest on record):

It was clear that the spell of extremely sunny, warm weather was ending during August. That, to me, was the great test for my melting momentum theory. Weather conditions switched, but for a week or so extent loss was keeping up with 2012's pace, despite the boost provided by the GAC. But then halfway through the month, things slowed down to a crawl after all (see red trend line):

So, what happened? Of course, there was a cyclone that was in a perfect position to disperse the ice, but there was so much weak ice that in my view, momentum should have gone on for a while longer.

There are two possibilities:

1) There wasn't as much melting momentum as I assumed.

2) Melting momentum is less important than I think it is.

As said, it took a while for melting momentum to get going. Timing is of the essence when it comes to breaking melting season records. May was actually very sunny this year, but most of the radiation coming from a Sun at a still low angle, got bounced off the pristine white ice. It may sound counterintuitive, but before the real melt ponding gets going due to open skies, cloudy weather is actually worse for the ice, because with clouds comes humidity and the clouds also block outgoing radiation. This can cause the snow on top of the ice to melt just a tiny bit, deforming the structure of the snow, making it more prone to melt when the sun starts to shine in earnest. 2019 came short in this respect, as evidenced by visual inspection of satellite images. Never mind the fact that the 2018/2019 freezing season was much less spectacular compared to the previous three winters, when it comes to temperatures and extreme weather conditions.

I'm still convinced that without a decent amount of melting momentum no records will be broken. That's why in years like 2016, 2017 and 2018 it was possible to announce at an early date that the 2012 record was safe. But conversely, a massive amount of melting momentum doesn't guarantee records either. Initial ice conditions and late stage weather obviously play important roles as well.

Maybe I'm emphasizing melting momentum too much, but I still feel kind of vindicated by recent developments on the extent front. Over the last week, just a small amount of weather conducive to melting has helped nudge 2019 below the 2007 and 2016 minimums, with quite an impressive run of daily drops. Tomorrow or the day after, the 4 million km2 mark could even be breached. I always thought that this year would come in second whatever would happen, and it looks like it has:

Either way, after almost 10 years of blogging, I'm now clearly seeing the contours of that first year when ice-free conditions will be reached (in other words, an ice cover smaller than 1 million km2, which amounts to ice-free for all practical purposes). It is preceded by a freezing season similar to that of 2015/2016, starts with the melt onset 2012 saw, builds up the massive melting momentum of 2019, and ends with the crazy weather of 2016. It makes me shudder to think what the satellite images will look like then. It may take more time than most cryospheric scientists think it will take, but unfortunately, that's not much of a comfort.

The ingredients are there, AGW is the cook.

Arctic sea ice / Re: The 2019 melting season
« on: September 16, 2019, 03:31:20 PM »
Hey folks, sorry I've been away for a bit. Unfortunately, discussing the CAA ice here is necessarily low on my list of obligations. There's been some question about how the current ice regime will interact with the traditional "garlic press" process of the CAA. Short story: there's not much garlic left to press.

The way the garlic press is supposed to work, thick MYI at the southern boundary of the CAB gets forced into the steep channels of the CAA resulting in additional ridging and compaction. Over a number of years, that ice is eventually delivered south into melt-accessible areas. All of this works because the average prevailing wind pattern in the region forces that ice into the archipelago and then south (and, to some extent, southeast). This process is the primary reason why the ice in the CAA has traditionally behaved very differently from fast ice elsewhere (although the channel size and bathymetry of the archipelago would otherwise suggest that CAA ice is comparatively uninteresting fast ice).

This melting season did a lot of damage to these assumptions. Most of the season was spent with an atypical wind pattern that forced ice from the CAA/CAB boundary north against the CAB and west into the Beaufort. Thus, the Crack was born. Additionally, while this wasn't a record-setting year for CAA melt, it was pretty devastating nevertheless. Massey Sound was a killing field for ice. The Peary and Sverdrup Channels have some ice only by dint of latitude. In the Perry Channel, the surviving ice (primarily associated with the Viscount Melville Sound) has been forced by late storms to the southwest into areas that are frequent melt-out traps. The region that has been the temperature "cold core" of the archipelago in historical data wasn't actually very cold; ice in the PGAS is badly fragmented and exceptionally mobile, and even the sheltered ice in Wilkins Strait looks more than a little roughed up.

More importantly, what remains of the MYI -- the tiny, thin line of red on the age maps -- has been displaced north into the CAB, away from the CAA boundary. The Crack has filled as the wind patterns return to their expected directions, but the ice that filled the Crack is not that MYI stopgap, but an assemblage of broken bits transported in from elsewhere, including no small part of relatively young ice from the Lincoln Sea area. This is not robust garlic for the press. It's reasonable -- one hopes -- to assume that wind flow will indeed push ice south into the CAA. But this ice has demonstrated considerable structural weakness. So I expect floe disintegration rather than ridging as the disparate floes are forced together. Winter's cold will mitigate some of this, and the whole mess will freeze into a matrix of FYI (effectively fast) ice.

The overall trend for the Arctic is, of course, hotter with more melt. But as we've seen this year and the past couple, that melt is not always distributed in the same pattern year over year. If we get a year or two where the melt focus turns away from the CAA, and we don't see Crack 2 in 2020, the garlic press will likely crank back up for awhile anyway. Otherwise, within a couple of years, we may very well see what happens when the CAA explores a new modality (as we're already seeing with Bering/Chucki mechanics).

Arctic sea ice / Re: The 2019 melting season
« on: September 16, 2019, 01:15:41 AM »
It's not a denialist mistake to be wrong. Everybody is wrong sometimes with their predictions. It's just a mistake. What do we call people who voted for BOE option THIS YEAR, during this melting season. Or do you think that was more realistic than weatherdude's prediction. They were just wronglike him. That is it. No conspiracies or hidden meanings behind every false prediction. Some are more realistic, some are less.

Hi colchonero, I agree with you. Regardless, I don't think you understand the context for this specific poster. They post denialist rhetoric on other forums like americanwx and then disappear whenever SIE or SIA goes back to low values. They seem to have registered here to do the same.

I agree with making falsifiable predictions and verifying them, in fact I have one coming up in just a few days that may bust that I will be posting about! It is not his prediction I have a problem with, it is his hubris: "Despite all of the hyperbole and wish casting, 2019 will not be in the top 3 lowest sea ice minimums on record in area or extent."

And note that this is not the first time this specific user has done this on this forum or elsewhere. Without this surrounding context I would have not been so judgmental.

Arctic sea ice / Re: MOSAiC news
« on: September 12, 2019, 10:49:03 PM »
osi-saf ice drift over summer for the mosaic startup area, jun-sep11 (every 2 days to reduce file size).

Arctic sea ice / Re: The 2019 melting season
« on: September 12, 2019, 09:20:38 PM »
NASA was kind enough to present 1984-2019 animation about it

The latest NSIDC "quick look" sea ice age map:
A sizable fraction of the remaining older ice is currently being sucked down the Fram, after several weeks of no export. And another small part is being melted in the dwindling Beaufort arm. Regardless of this year's minimum, a lot of damage has been done, and 2020 will need to dodge another bullet.
OTOH, we can at least be thankful that the FYI from Laptev to below the pole has manage not to melt out. With different August weather this could have been open water now, after the terrible June and July.

Arctic sea ice / Re: The 2019 melting season
« on: September 12, 2019, 09:15:20 PM »
According to Jim's graphs, ice volume has decreased from 14.9 to 4.7 * 1000 cu. km from mid 80's to now
This represents approx 0.35 * 1000  cu km change / year  at time of minimum volume. Assuming a BOE occurs  when there is 15% of the 16,000,000 max in 1980 and an average thickness of remaining ice of 1 metre, the volume at a BOE would be 2.4 cu km
Therefore , at 0.35 * 1000 loss in vol / year , we could expect a BOE in (4.7-2.4)/0.35 = 6.6 years
This makes a big assumption - that system behavior will be consistent as we reach that limit.

Based on the surprising end of season slowdown this year, I'm not sure that's safe. I'm still mulling hypotheses for what we are seeing and why the dynamics are not falling more in line with your assumptions. 

"Blue Ocean" is a boundary condition, and the retreat of the ice to where it stands now - post 2007 - suggests to me that the dynamics for the ice north of 80 are significantly different from those of the peripheral seas, which is were most significant visible changes in the Arctic have unfolded.

The ice in the CAB and along the CAA by dint of higher latitude appears less influenced by the effects of insolation and atmospheric heat.  It is also *somewhat* protected by the deeper waters of the central basin.

I  think it will require more import of oceanic heat - from the Atlantic side in particular - to push the system out of the state I think it may have settled into.

I think we may see quite a number of years like this - following the pattern of post 2012 - with the ice retreating to the high-latitude bastion we see.

We *could* see a weather driven event driving a season below 2012, but am leaning more and more to a conclusion that this would be anomalous rather than a signal of impending BoE.

I think we need a lot more data on changes in Arctic ocean enthalpy changes, as I'm thinking that and attendant changes in water column structure are what will drive us to a BoE.

Arctic sea ice / Re: The 2019 melting season
« on: September 12, 2019, 01:43:44 PM »
On that note, how's that multi-year ice doing in 2019?
It's doing exceptionally well: practically all of it is in sea ice's heaven now. Gone to better world, it is. No more suffering from all the greenhouse effect, bottom melt, rains and melt ponds all over it. RIP, MYI.

NASA was kind enough to present 1984-2019 animation about it - see yourself, in which amount of ice 4+ years old is practically zero by July 2019.

Arctic sea ice / Re: The 2019 melting season
« on: September 09, 2019, 06:09:29 AM »
States what? Edit: Ah, no worries. I'm pissed off and seeing red too. Hard to focus with so many *&^% bombs landing every which way... :)

In other news, I'm starting to wonder if early maxima may not become more common in the future: We have apparently already crossed the warming threshold for peripheral melt in the shallow seas to become a yearly phenomena, and to occur earlier and earlier. Conversely, the threshold for yearly melting in the deep CAB takes an extra ? years, and in the meantime, the CAB melt is more or less dependent on the seasonal weather. So in years like this, with protective late-season weather, the peripheral melts out completely earlier and earlier, while the central basin clings on...

Arctic sea ice / Re: The 2019 melting season
« on: September 08, 2019, 09:57:13 PM »
I suspect that the famous bottom melt, as kind of a negative feedback, is not anymore what it used to be.

As luck would have it the NSIDC discussed surface versus bottom melt in the the latest Arctic Sea Ice News:

"Summer’s not over until bottom melt ends"

Although Arctic air temperatures are now falling below freezing, sea ice loss will likely continue for several weeks as heat stored in the ocean melts the underside of sea ice.

Here's the accompanying graph. The caption reads:

This 2005 to 2006 time series from the Beaufort Sea shows ice thickness (red line), growth rate (blue bars with negative values), bottom melt (blue bars with positive values), and surface melt (dark blue line with points). Both surface and bottom melt started on June 10. Surface melt peaked on August 1, and peak bottom melt was two weeks later on August 15. Surface melting ended on August 24, while bottom melting continued until October 24.

Arctic sea ice / Re: The 2019 melting season
« on: September 07, 2019, 10:32:02 AM »
Time to restart the thread about refreezing season now Neven?🙂

Nope, after the minimum.

Arctic sea ice / Re: The 2019 melting season
« on: September 07, 2019, 09:42:16 AM »
the slush that counts for extent these day
Well said. But I would say the Arctic has managed to dodge a cannonball in summer (August). It could be worse now.  I'm concerned about the SST and the possibility the ice won't recover this winter and next melt season will start with record low volume.

Arctic sea ice / Re: The 2019 melting season
« on: September 06, 2019, 06:44:43 PM »
NASA put a nice animation of arctic ice loss online

Two take-aways for me: The Fram export starting up is nothing less than expected and the persistent arm in the ESS is a tail of MYI that made a full clockwise circle on the edge of the Beaufort Gyre, snapped off in the summer.

Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: September 04, 2019, 05:03:28 PM »
To me, even though 2012 was significantly lower in extent, 2019 look much worse.
2012 at least looked solid in the middle.
2019 looks like it is shattered to pieces.

I totally agree.  This is why I think ANY curve-fitting exercises using extent are a fools errand.  A-Team said several times "A complete late summer blow-out can happen any year" (or very similar words).  I would be shocked if we don't see, by 2030 or before, the late summer pack reduced to separate, isolated patches of ice pushed by wind and current against isolated islands and shores on the Atlantic side.

Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: September 04, 2019, 10:11:17 AM »
To me, even though 2012 was significantly lower in extent, 2019 look much worse.
2012 at least looked solid in the middle.
2019 looks like it is shattered to pieces.

Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: September 04, 2019, 09:07:31 AM »
A late century drop in extent shows there are still possibilities for second lowest place ( in my limited data set).

Here is an animation of the Arctic Basin compared with 2012. Click to start.

Arctic sea ice / Re: The 2019 melting season
« on: September 03, 2019, 09:13:59 AM »
Marcel you are correct, it was 2015 we watched "Big Block" spin its way to oblivion in the Beaufort. Since then I have seen nothing even similar to how robust that ice was.

We are probably unlikely to again in our lifetimes.

Arctic sea ice / Re: The 2019 melting season
« on: September 02, 2019, 04:56:15 PM »
Ghost ice in the Beaufort today.

Indeed. Ice is definitely "$&!^", as someone said.

It's fantastic how extent and area stalled so dramatically, even while continued melting is apparent (and before refreeze has really started). PIOMAS also has known limitations for thin ice. It seems that, as the ice continues to thin Arctic-wide and the weather goes bonkers in different ways, we don't have any good way to measure actual melt. I imagine this state of affairs could make for a pretty shocking year... eventually. But I'll go out on a limb and predict that it won't be this year.  :P

PS. Re: Freegrass' animations. I think grixm was referring to storage space on the server. I don't know if this is actually a problem, as I've never seen Neven mention it (if so please do). And there are a large number of downloads of Fregrass' products, so I'd suggest he keeps it up!

Arctic sea ice / Re: The 2019 melting season
« on: August 29, 2019, 05:42:38 PM »
That graphic of ice movement vectors overlaying the U. Hamburg ice map is most useful in showing that the stall in extent drop has not been caused by a stall in melting. Bottom melting has continued while the ice has been dispersed by the weather for the past week. The apparent stall isn't really good news for sea ice. The ice volume is still very low as we shall soon see in PIOMAS.

This melting season has been very interesting and complicated.

I think we are going to see one more period of extent drops. There is too much heat in the Arctic ocean for bottom melting to stop in the next week, so don't call the melting season over just yet.

Arctic sea ice / Re: The 2019 melting season
« on: August 29, 2019, 01:42:06 PM »
The excellence tournament among data artists at ASIF continues to astonish. What an awesome, eloquent product from uniquorn! (Please forgive my abject hero-worship.)

Arctic sea ice / Re: The 2019 melting season
« on: August 29, 2019, 12:41:32 PM »
As there is some discussion about ice drift direction, here is osisaf ice drift overlaid onto unihamburg amsr2-uhh, aug18-28.
Arguably amsr2 should be overlaid onto the previous 2 day osisaf but 1 pixel of amsr2, ~15km^2 of slush probably has a fair bit of inertia so in this case day n-2 to dayn osisaf is overlaid onto dayn amsr2-uhh(25-27aug onto 27aug)
Note that although both products use algorithms to interpret the data, both are based on real data and not models.

Low Resolution Sea Ice Drift product (OSI-405)

Which satellite sensors are processed?
The sensors and channels used are SSMIS (91 GHz H&V pol.) on board DMSP platform F17, ASCAT (C-band backscatter) on board EUMETSAT platform Metop-A, and AMSR-2 on board JAXA platform GCOM-W.

What is the spatial resolution of this product?
The low resolution sea ice drift product is a gridded dataset. The grid has 62.5 km spacing on a Polar Stereographic projection mapping. Definitions for the projection parameters can be found in the NetCDF files as well as in the Product User's Manual.

What is the time-span of this product?
Two days (48 hours). This is the time delay between the start and the stop time of the motion described by one vector. For comparison, the merged products from IFREMER/CERSAT is a 3 days lag dataset while the AMSR-E product by the same data centre is 2 days (using 89 GHz channels).

Several datasets are distributed every day, which one should I use?
The OSI SAF low resolution sea ice drift product is indeed composed of several single-sensor products and one multi-sensor analysis, every day. They are all at the same spatial resolution , on the same grid and with a 48 hours time-span.

The multi-sensor (aka merged, multi-oi) is intended for users requiring a spatial covering dataset. In this product, missing vectors are indeed interpolated from the neighbours and each vector is computed from the individual single-sensor products. In this merging process, however, some level of aliasing and averaging is to be expected that slightly degrade the quality of the dataset.
click to run

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: August 27, 2019, 11:38:07 PM »
Considering momentum, heat in the water and everything else, the slowdown over the last week is nothing short of astonishing to me.

I really didn't expect to be wrong concluding extent this year would drop under 4 million KM2, but am happy that it appears it won't.

As I said elsewhere, seems there's a factor we are missing somehow.

Arctic sea ice / Re: The 2019 melting season
« on: August 27, 2019, 01:21:03 PM »
unihamburg amsr2-uhh comparison of aug26  2012, 2016 and 2019
added scale ;)

Arctic sea ice / Re: The 2019 melting season
« on: August 27, 2019, 06:35:19 AM »
I prefer to look at 4 km Masie area it is far more accurate than the 25 km resolution data. I would like to use the 1 km data but it doesn't even go back to 2012. It shows the results of all the heat in the ocean better.

Arctic sea ice / Re: The 2019 melting season
« on: August 27, 2019, 05:15:36 AM »
I don't know how much ice will melt, but it really looks in bad shape. Like on box, maybe the ring will save it. Or maybe not. Just a coin in the air.

The rest / Re: Are you hoping for a global civilisational collapse?
« on: August 27, 2019, 05:06:28 AM »
I don't think this poll is well-worded.

I go for both
"I expect that global civilization will collapse within the next few decades" for which I voted, and
"I hope that global civilization will not collapse in the foreseeable future".

Arctic sea ice / Re: The 2019 melting season
« on: August 27, 2019, 03:28:11 AM »
Heat is radiating out from the cloudtops and above so the polar atmosphere is becoming increasingly unstable as we move into September. The models are struggling to capture what's happening more than 3 or 4 days out.

There's still the potential to melt out dispersed ice on the Siberian side of the pole but the horse race is now for the second or third position. It's a good thing that 2012 is looking unbeatable. The fires in Siberia and the Amazon have been depressing enough. We don't need to see any new sea ice records this year to get the message across that the climate is in trouble.

Arctic sea ice / Re: The 2019 melting season
« on: August 27, 2019, 12:53:59 AM »
The slow down started two weeks ago when increases in concentration were reported first, perhaps a sign that melting momentum was being exhausted.
However there was still potential for extent losses, and the weather I would think was conductive to those losses. But did not happen. Yet I expect more significant drops before mid September. Tomorrow’s concentration map will show an even more disperse and degraded pack than Today’s.
Edit: image is tweaked to reveal intact areas of ice pack. Original:

I would like to go on record as saying that ice looks worse than I have ever seen it at the end of a melt season.

Arctic sea ice / Re: The 2019 melting season
« on: August 26, 2019, 03:04:13 AM »
I forgot to add this post from Lars Kaleschke today. It shows areas where extent is likely to start dropping soon. 

Arctic sea ice / Re: The 2019 melting season
« on: August 26, 2019, 02:55:32 AM »
I just have one very scientific thing to say ... the ice looks like Shit!

The Laptev and Beaufort are getting hammered.  The extent in Beaufort is going up, but the ice that is getting flushed into the south Beaufort is the last of the multi year 5+ ice. 

This year is unlikely to break records for extent (although it is still too early to rule that out for certain) but, the ice going into the freezing season is going to be about the worst it has ever been. 

Just play around on Worldview for a few minutes.  It looks terrible.

Arctic sea ice / Re: The 2019 melting season
« on: August 25, 2019, 03:53:19 PM »
I hate to say this, but this is the main thread, and its quality has deteriorated a lot this year. We used to have fewer posters with relevant stuff, most often supported by data/graphs; but now we have lots of OT and random musings and (seemingly not very knowledgable) people who post many times a day lengthy posts without much (if any) substance or new, relevant information. I used to read every post on the melting/freezing threads because I could learn from them, but nowadays I skip most because they are more or less worthless. If I were the moderator I would ask everyone if possible to do short posts, only with real, significant data and concise analysis and let's do the philosophizning on other threads.
I hope (wish) the freezing season thread would be different...

People learn best by doing. These kinds of rants are, whether intentional or not, aggressive, rude and patronizing. You are basically saying this board should never change, new people, with their learning curves, should ever post; it is only for the "elite", already-knowledgeable.

There's an opportunity cost in having an ignorant populace; I'd think you'd want as many people as possible to be engaged with these issues.

Your view is one way for the forum to operate. I'm merely pointing out a potential flaw in your argument.

Arctic sea ice / Re: The 2019 melting season
« on: August 22, 2019, 09:35:10 AM »
I doubt this storm will provide much melt,  it is both geographically and temporally in the wrong place for a large melt caused by dispersion or compaction.

The 2012 storm was earlier and over the central Arctic  while this is later and mainly over land.

I'm new to this board and while there is a fantastic amount of data and science on here it surprises me that there is so much desire for melt and records rather than just watching it and learning; it should be about what happens, or potentially happens, not what you want to happen.

From what I can tell, I don't believe many here WANT record lows and melt. Because many here understand what that means for the planet. I think really what it is about is interest.

The volume and volume-anomaly graphs.

Arctic sea ice / Re: The 2019 melting season
« on: August 20, 2019, 02:06:12 AM »
update on caa/cab crack, unihamburg amsr2-uhh, may1-aug18

Love these, thank you! The remaining CAA ice is loose. What will the upcoming cyclone do to it? Could be dramatic...

Arctic sea ice / Re: The 2019 melting season
« on: August 20, 2019, 01:25:45 AM »
update on caa/cab crack, unihamburg amsr2-uhh, may1-aug18

Arctic sea ice / Re: The 2019 melting season
« on: August 19, 2019, 08:19:02 PM »
That's a cold blow to the Pacific :)
It looks like it could be the last hot air that's leaving the arctic.

Arctic sea ice / Re: The 2019 melting season
« on: August 19, 2019, 08:06:56 PM »
Are the ESS remnants melting???
Looking at the worldview it each day it seems a huge amount of floating debris won't go.
Actually these last days south winds are causing a noticeable decline.
Some of these things seems will remain for some time yet!
The horizontal cut is maybe two or three hundred kilometers long.
Notice the two blocks of ice surviving fastened to the shallow sea floor (I don't think these are islands...?)

Arctic sea ice / Re: The 2019 melting season
« on: August 19, 2019, 07:43:04 PM »
Am I going crazy or is there a LOT of ice being exported thru the Fram and Svalbard right now?

Nope, not crazy. Clouds make it hard to look in recent days. Good, there is radar.

Arctic sea ice / Re: The 2019 melting season
« on: August 19, 2019, 07:09:01 PM »
Latest forecast.

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: August 17, 2019, 03:53:39 PM »
Is there anything about 2019 that is exceptional? If I understand, 2012 was exceptional because of a big cyclone in the Arctic (am I right)? Is 2019 just a near "normal" year?

     Seems to me that 2019 stands out for the overall poor quality of the ice (thickness, concentration).  Extent and Area do not necessarily reflect that poor condition  so even though it seems unlikely that 2019 will set new low Extent record, it represents another step down the path of arctic Sea Ice degradation, and all that that implies for the climate system as a whole. 

    One aspect the current situation that stands out to me is that the largest chuck of highest concentration CAB ice is on the Atlantic edge.  Very doubtful it will happen in the dwindling melt season, but a cyclone to export that chunk out of the CAB would make a big dent in the Extent/Area/Volume stats.  Though it probably won't happen, just the fact that it could is ominous.  And that IMO is the ASI headline for 2019 -- the ice is in worse shape and more vulnerable than ever. 
   As somebody commented above, this degraded state is occurring at/near minimum of a weak solar cycle.  Our friendly star is remarkably stable but the slight variation in energy received from the sun across solar cycle can nudge annual average global surface temperature up and down by ca. 0.1C.  So with ASI in this shape in 2019, what happens at peak of next cycle (albeit also expected to be relatively weak amplitude cycle relative to past 100 years)?  And of course with GHG emissions roaring along, and 93% of the extra retained energy going into the ocean waters, add that to next solar peak in 5-6 years and 2012's freak low Extent/Volume could start to look like the good old days when there were still millions of km2 MYI sea ice that carried over between years.

   So I guess the 2019 headline could be the beginning of the end for the ASI functioning over the last 12,000 years as a climatic anchor and stabilizer during the Holocene period.  That's the period during which so-called  "wise apes", aka Homo sapiens, learned how to do things like agriculture, science, literature and all the rest.  All just my lurker opinion of course.

     Climate sanity should be a requirement for any policy and politician to even be considered.  As the World Bank put it in back in 2012 (before the last 7 years of sooner/more severe climate study results) - the continuity of an "organized global community" depends on it.  I confess that I find it numerically fascinating to learn about the complex interactions of the ASI as it falls apart.  So a preliminary thanks to Neven, gerontocrat and others for hosting this soiree again this year.  But I don't want to see what "disorganized" global community looks like.  It would be nice if there was no reason to enjoy this forum.     

Arctic sea ice / Re: The 2019 melting season
« on: August 16, 2019, 06:20:16 AM »
Its very unlikely that 2019 will finish below 2012 in extent.

I would give it a 1 percent chance.

AMSR2 SCANS USING THE 36GHZ AND 18GHZ wavelength shows the whole of the ice pack left regardless of concentration is to thick.

There is just not enough energy coming in from the sun to support melting the ice North of 80 at the level needed to beat 2012. 

Arctic sea ice / Re: The 2019 melting season
« on: August 15, 2019, 09:23:13 AM »
Weather forecast for the next 4 days.
This is so cool... :D
Thanks PETM!
I ended it with the smiley face that's still in the forecast... ;)

It looks like the southern part of the CAA will melt out, and the state of the Eurasian side of the ice + forecast suggests significant losses on the way.

How much of the northern CAA will hold out?

Will this wind finally drive the ice off of the Atlantic Islands where they've held on stubbornly all season? And will that result in any retreat of the ice along the Atlantic side where positive concentration anomalies are high?

Will the Beaufort be able to swallow all of the ice being pushed into its waters?

Any crystal ball owners out there?
We are now past the peak of insolation, and the remaining ice is for the most part above latitudes that will receive significant insolation between now as the equinox.

Heat blowing in from the continents will have a minimal effect, as it isn't accompanied by significant insolation or long-wave radiation.

All hinges now on bottom melt, and to a certain degree, on how much heat is pulled from depth by wind.

I think a 2nd place finish is pretty close to being "in the bag".  I'm doubtful that we will pass 2012 - *UNLESS* the melt season continues into late September, driven by bottom melt.

Unfortunately, that store of heat - what's already in the water - is an aspect of the Arctic we probably have the least information on.  We can only wait and see what transpires.

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: August 14, 2019, 02:03:10 PM »
As it is 31 days, one month to the 10 year average minimum date**, here are some extras.

ARC5:- The plume of projection from remaining extent loss of the last 10 years, all below 4 million km2..

ARC6:- Table showing that if extent loss stopped now, 2019 would be 11th lowest since 1979.

ARC8:- Table of daily extent losses from now to minimum in selected years (for those who like numbers)

ARC7:- 365 trailing daily average - that could be at a record lows again in early 2020.

** The minimum will be on 13th September. I have said it, and so it is thus.

Arctic sea ice / Re: The 2019 melting season
« on: August 14, 2019, 03:20:53 AM »
Ascat with NSIDC ice age overlaid at 20% transparent, mar21-aug12. Not the cleanest animation but here attempting to highlight Oren's comment about first year ice upthread.
The ice age product is weekly and has been duplicated so that the dates should match (edit: except for this week). When this week's ice age map is released I'll try an overlay with amsr2 which should be cleaner.
ice age colours are altered slightly by the transparency
If anyone should study just one animation this season, let it be this one by uniquorn. The ice age correlates well with Ascat, and is distributed in a very lopsided manner around the Arctic.
It's mid-August and the season is getting long in the tooth, but I think the ice "above" the Pole is still vulnerable, being First Year Ice, and quite rubbly. It's hard to know how much top and bottom melt has already occurred, but some of this ice could be nearing a threshold. We will know soon enough.

Arctic sea ice / Re: The 2019 melting season
« on: August 13, 2019, 10:34:09 PM »
I've been somewhat hesitant to post about the weather forecast, but this week's forecast is too interesting to ignore. For about a week now, the models have been predicting a big surface high over the East Siberian sea, with surface low pressure around the Atlantic ice front/Barents and moderately low pressure as well around the eastern Alaskan coast toward the Beaufort sea. For example compare today's ECMWF initialization shown below with that of seven days ago, and you can see that last week's forecast for today verified quite closely:

What is interesting to me is that the op EC model keeps today's pattern roughly in place for the next week. The GFS and Canadian also support that idea, with the ESS high arcing gradually toward the Alaskan coast and the Atlantic side low drifting over the central ice.  Regardless of the nuances, the Siberian coast heat wave and the consistent southerly winds from the Laptev sea area should test Friv's hypothesis.  Friv had suggested up thread that the ESS didn't melt out early enough this year to allow the open water to warm enough that it could really attack the CAB ice late in the season.  That seemed reasonable at the time, but this extended warm period along Siberia, and the extended periods of southerly winds from Asia toward the pole makes it interesting. I wonder if there is still enough sun power to really heat that newly open water along the ESS and Laptev, and if the fetch of southerly wind would be enough to transport some of that warmth toward the central ice over the next week or two?

Arctic sea ice / Re: The 2019 melting season
« on: August 13, 2019, 09:43:14 PM »
I've been following this forum for many years now, content with a daily intake of the latest data and all the different opinions and views regarding them. As i read an article of the dutch metereological society today, i thought this might interest some of you. I guess this is not the right thread for it but i couldn't find a better place. Please feel free to move it to a more appropriate thread.
According to research by the dutch KNMI and the university of Exeter (published in Nature Climate Change), reduced sea ice extent does not lead to cold continents at moderate latitudes, the so called warm arctic cold continents theory or WACC.
Instead it is a fluctuation in atmosferic circulation wich causes simultaneously the decrease in sea ice and cold waves at lower latitudes (Northern America). They tested the WACC theory by using 2000 years of climate data. They divided winters in two groups: one in which the atmosphere clearly drives sea ice behaviour and another group where sea ice forces atmospheric circulation. It was shown that only the first group results in the WACC pattern and they conclude that a lack of sea ice does not cause cold waves in Northern America. A further model simulation showed that further reduction of arctic sea ice will lead to higher arctic temperatures but not invoke the WACC pattern and thus will not lead to more cold spells at lower latitudes. For the article at the website of the KNMI (in dutch, but there is always Google translate, and with some figures illustrating things) see:

Arctic sea ice / Re: The 2019 melting season
« on: August 13, 2019, 09:02:44 PM »
They are both wrong.

And back to the point, we are in some control of where the climate heads although we cannot control the details and we are struggling to understand the complex interactions between the ocean, ice and atmosphere. It's shocking to me that the Arctic ocean is so thinly observed given its key role in earth's climate. The few buoys we have making observations of the upper ocean show heat at about 50m that the Mercator model is missing.

Careful observation of individual floes shows that A-Team is correct that the ice does not directly follow wind streamlines, sea surface height gradients or ocean currents. It is affected by all of them, plus it compresses and forms ridges. Below the surface, we have sparse measurements of the movements of water masses. We're still trying to untangle the effects of the GAC in 2012 on the sea ice because we have don't have dense enough data on Arctic ocean heat content changes through the melting season. And "we" includes the sea ice experts who don't do significantly better at predicting September extent than this ragged group of interested observers. For a variety of reasons, but mainly because we can't predict seasonal weather well, the expert's models don't work very well.

Ironic, isn't it that the one thing we do know pretty well, the effects of CO2 on paleoclimate, has been so poorly explained in this melting thread. Geothermal heat has an inconsequential effect on climate.

Solar heat and all the factors that affect the earth's radiation balance control the climate. Greenhouse gases are among the most important controls and CO2 is the key gas over the past billion years. The modern climate is paradoxical because the sun was cooler in the precambrian than it is now. Of course, we know that declining CO2 levels over the past 25 million years led to the onset of the Pleistocene and the ice ages. Those declining CO2 levels we mostly caused by increased rock weathering rates associated with the continental collision of the Indian plate with the Eurasian plate.

So while we watch the impacts of unprecedented ocean temperatures in the far north Pacific and Atlantic oceans, and shockingly warm Arctic seas, on Arctic weather and sea ice, two proudly ignorant fools are clogging this thread with arguments that ignore the effects of CO2 on climate. Siberia is literally on fire, thunderstorms are approaching the north pole and the Arctic oscillation has been stuck in hot subsidence mode almost all summer and yet some folks here don't seem to get that rapidly increasing CO2 levels are the primary cause of all of it.

Click image to animate. The heat keeps on coming into the Eurasian side of the Arctic.

Arctic sea ice / Re: The 2019 melting season
« on: August 13, 2019, 07:31:39 PM »
All very true, but perhaps fit for another thread?

Also true but i think the false information cannot simply let be and then until now nobody could show me a decent way how to correct such an obvious false information so that it won't spread to the general public via PM.

Say the person is wrong and then invite him/her to the appropriate thread.

Arctic sea ice / Re: The 2019 melting season
« on: August 13, 2019, 06:06:22 PM »

It would be interesting to know how much ice the Barnes Ice Cap lost this yet. It seems to have been under blue sky for most of July and August.

A remnant of the last ice age. It will not survive to see the next.

Next ?

100,000 years from now

We are STILL in an ice age. What we are experiencing is the Earth's climate transitioning from a interglacial to a hothouse state. My guess is it'll take a few million years to switch back to icehouse. Go on; Prove me wrong.

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