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Messages - subgeometer

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1
Arctic sea ice / Re: The 2019 melting season
« on: July 17, 2019, 07:32:02 PM »
Take your time with family, Neven. I'm so sorry about your loss. We'll carry on here.

2
Arctic sea ice / Re: The 2019 melting season
« on: July 16, 2019, 06:17:19 AM »
Maybe I misunderstood him, but I thought he was talking about the ESS.  I don’t think there are any glaciers over there calving ice bergs, but I’m happy to be corrected if I’m wrong.  🤔

3
Arctic sea ice / Re: The 2019 melting season
« on: July 15, 2019, 10:30:18 PM »
When this season is over and we can compare what happened to what we expected, will that help us predict 2020 better?

I doubt it.

4
Arctic sea ice / Re: The 2019 melting season
« on: July 11, 2019, 09:47:25 PM »
You guys are completely overestimating how hard it is for the ice in the cab to melt north of 80 degrees north.

We haven't had that peak Insolation hit the CAB

A new record is unlikely.
Almost all ice North of 80 in the Laptev side is the FYI. It can melt out even if it Will stay in the High Arctic. Also we'll have early melt of the peripheral seas, the highest SST, more killing zones for the CAB ice that Will drift to the south. The melting season can Last longer due to the Ocean extra heat accumulated + more possibility of strong storms

5
Arctic sea ice / Re: The 2019 melting season
« on: July 10, 2019, 12:08:09 AM »
For those interested in anecdotal evidence of what happened in 2012 around this time, I can highly recommend my own writings (someone has to do it) on the ASIB at the time: ASI 2012 Update 6: piggy bank

It corroborates a lot of what friv is saying.

6
Arctic sea ice / Re: The 2019 melting season
« on: July 09, 2019, 10:02:56 PM »
XXX-rated Pole Hole showing up on 12z EURO

For when is the forecast, who is making it, and how trustworthy is this source? I've never seen this map before.

7
Arctic sea ice / Re: The 2019 melting season
« on: July 09, 2019, 06:47:06 PM »
PS what was the source by chance?
I really like the source - pogodaiklimat - because it has graphs of the past and not just a forecast like most weather sites. It compares with daily climatology. It shows a whole month at a time. And archives the graphs of past months and years that you can access at the bottom of the page.
Downsides are that it's in Russian (Google translate to the rescue), and only covers Russia and ex-soviet states, world big cities and the USA (but not Northern Canada or Greenland).

Here are my bookmarks plus a few others I managed to find now thanks to your question.
www.pogodaiklimat.ru/monitor.php?id=21432   Kotelny Island
http://www.pogodaiklimat.ru/monitor.php?id=21824  Tiksi
http://www.pogodaiklimat.ru/monitor.php?id=25051  Pevek
http://www.pogodaiklimat.ru/monitor3.php?id=PABR  Barrow
http://www.pogodaiklimat.ru/monitor.php?id=21982  Wrangel Island
http://www.pogodaiklimat.ru/monitor.php?id=20069  Vize island (Kara/CAB/Barents border)
http://www.pogodaiklimat.ru/monitor.php?id=20046  Heiss Island (Franz Josef Land)

8
Arctic sea ice / Re: The 2019 melting season
« on: July 09, 2019, 04:32:54 AM »
The GFS is trending towards a cool Arctic

Does that mean cyclones, or cool and calm?

I’m totally confused too.  I think the take home message is that this is an expert interpreting long term model results.  His interpretations are accurate, but long term models suck so we will wait and see what happens.  😝

9
Arctic sea ice / Re: The 2019 melting season
« on: July 08, 2019, 10:52:42 PM »
I've opened a special thread to specifically discuss the differences between 2012 and 2019. Be sure to read the rules, and please, post lots of maps, graphs and satellite images that show these differences.

Of course, you can post them here as well.

10
Arctic sea ice / Re: The 2019 melting season
« on: July 08, 2019, 09:14:37 PM »
In the meantime...Slater's model is pretty much unchanged the past few days.

Expected extent on Aug 27,2019: 4,31 M sq km

NSIDC extent on the same day of

2012: 3,94
2016: 4,77
2007: 4,83
2017: 5,00

Based on this, unless something extreme happens In July/Aug (superheat and or a big cyclone), it still looks like 2nd place for 2019.
What did the Slater model predict on this date for August 27, 2012? I'm betting that the prediction was more than 4.31Msqkm.

11
Arctic sea ice / Re: The 2019 melting season
« on: July 08, 2019, 02:13:50 PM »
A big P.S. also to my post, beyond the fact that June 2019 was abysmal, I wanted to show also, even though it was not explicitly state, that Sun input is increasing bigly in Arctic, with an increase of 1 W/m² in June every four years. It could perhaps have been better to wait MERRA, but the topic was brought again in this discussion so go. But even more importantly, no matter if 2019 is at record or not, we are witnessing the effect of increase Sun input, with Chukchi, Beaufort and Bering running like bats out of hell after records. Of course, it is a progressive state change, but I fear we are nearer and nearer to the point that Bering sea will be perennially open, and even Chucki sea looks to be already in bad state for a good refreeze this winter. If ocean is warm enough, I think that it could supply enough moisture to create a positive feedback with longwave radiation. The warmer, the moister, the moister, the less heat can escape to space. And the warmer, the longer it takes to cool down, and if heat is not able to radiate back to space, it will take even longer. And if a melt season can give hand to the next like it was almost the case last three years, Sun input in summer is going to go trough the roof, etc... Up to now, Arctic was more or less able to erase its memory of the latest melt season during winter, but when I see the SSTs going trough the roof and Arctic pounded by relentless warmth and sun, and the last 3 years, I fear we are reaching the point where it is no longer the case.

12
Arctic sea ice / Re: The 2019 melting season
« on: July 08, 2019, 01:43:15 PM »
...
I think what is missing here is a discussion of the impact of increased solar irradiance.
...

Are you talking about the reduced albedo, low cloud cover, something else?

Looking at only solar irradiance I believe we are at a solar minimum right now with a lower irradiance than in 2012 and most of the rest of this decade (even then that difference is tiny).

The low solar minimum that the earth is presently experiencing is not the key issue that I am talking about. Rather, the key issue is the amount of solar energy entering the system as a result of reduced albedo in the arctic. This difference far offsets the difference in energy coming from the sun due to the solar cycle.

I broadly agree, I have also the feeling that incoming solar radiation is probably a bit an understate factor. It is of course a know fact, and a spoken one, that lower albedo implies a greater heat accumulation. But perhaps that the big train of heat ready to ram us is not fully acknowledge. By the way this is why I'm back here, at ASIF. I'm like a vulture, when I smell the good fragrance of a water bath I am here.

So to continue this discussion, I will try something (each word of this sentence is important XD ). NCEP/NCAR Reanalysis is easier to manipulate and is update with a lag of a few days only. So I already us it, but radiations data are not as good as other dataset. Good enough to say something about big trend and to beat some dead horses, but probably not good enough for details -like the exact magnitude of the June 2019 crash-. MERRA is probably better but will not be available until mid or late July for the month of June. As already state, solar heat input in June above 70°N is a big factor : https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JD025819
With MERRA data up to June 2018 I am going to back up this claim and give some order of magnitude, and with reanalysis up to June 2019 I am going to show that this year things are worst than worse. I will update the analysis when June 2019 data from MERRA will be available in late July -when nobody will no longer care as sea ice extent will be many thousands squared kilometers below 2012 and the crash will be beyond obvious XD -. Perhaps MERRA datas are going to show a little miracle, against the reanalysis, but is not really likely.

I am going to use two different flux. With MERRA, I am using net downward flux at surface (SWGNT for short). State an other way, it is the solar input wich is really accumulating at surface. The part of the Sun wich is not absorbed can be reflected by atmosphere and surface, wich is going back to space as a outgoing shortwave radiation (RSR for Reflected Sun Radiation). And Sun can also be absorbed by atmosphere. I stick with SWGNT cause looking at RSR implies giving weight to heat absorbed by atmoshere, but I don't think this part of the flux is really important. Its variations year over year are not as important, and heat absorbed by atmosphere is probably going to be mixed all over the hemisphere in a few days (as a side note, aerosols and soots -also known as black C- implies that Sun is more easily captured by the atmosphere, wich also have implications for global warming. But, looking only at sea ice year over year, the Sun captured by the atmosphere is not looking like a big factor). So, with MERRA dataset, is is going to be SWGNT. But Reanalysis as not an easy dataset for this flux. I could be possible to mix surface albedo with the downward shortwave flux at surface, but it is starting to look a bit too shaky, given the accuracy of reanalysis. So, with this lad, I am sticking with shortwave outgoing flux at TOA (RSR in the state paper above). Of course, the higher the heat absorbed by the surface, the lesser the heat making an escape to space. As a consequences, many graphs are going to have a left hand y axis, and a reversed right hand y axis. So far, the brains already hurts XD

The first graph is September SIE and SWGNT. The latter is reversed, meaning that the more the Sun is absorbed at surface in June, the less ice survived in September. Correlation is looking quite good, so let's check this.

The two datasets are quite correlated, with a decrease of the September SIE of 1 million square kilometers if absorbed radiation increase by 7 or 8 W/m². It should be note also that extrapolating the trend brings plausible results, with a zero SIE if June heat input is up to around 150 W/m². Definitively in the realm of possibilities.

So now that we have checked we are able to replicate the results of the above study, and that sea ice is screwed if Arctic is pounded by Sun in June, let's look at what the reanalysis is saying about June 2019. Was it bad, or worse than worst ? Short answer, acording to reanalysis June 2019 is abysmal. Values from reanalysis for outgoing solar flux at TOA are correlated with values from MERRA for solar input at surface. Correlation is not so bad (R² 0.45), but 2019 is not a record low point (caramba ^^). This said, it is looking like reanalysis is not going down enough. What I'm going to do is to artificially increase the trend for USWRF. Not for the pleasure of making things looking worst, but because, without MERRA data for June yet, we can only guess what happened. And an educated guess will be that reanalysis is to shy (not a surprise here...). Correlation is improved (R² 0.55) and 2019 is to the basement. Again, this is not intended to manipulate data to prove that June 2019 is a nightmare, but it is really because it is quite probable that reanalysis is not going down enough. Correlation with September SIE is also vastly improved (R² up to 0.43, from 0.20 with bulk values). Again, it is not a surprise that adding a trend to a datset to compare it with a dataset -SIE- where the trend is overwhelming everything vastly improves the correlation -if the slope of a dataset is way higher than its variability, we can correlated it with about any dataset having also a big slope-. But I do think this as a physical meaning.

I let you also the values for SWGNT in June in W/m², and with a conversion to "how many meters of ice could be melt by such and heat input ?" to give a sense of the energy in play.

   SWGNT      Thickness elt
1980   107   0.90
1981   109   0.92
1982   103   0.87
1983   103   0.87
1984   108   0.92
1985   113   0.96
1986   99   0.84
1987   108   0.91
1988   109   0.92
1989   99   0.84
1990   117   1.00
1991   111   0.94
1992   102   0.87
1993   116   0.99
1994   108   0.92
1995   109   0.93
1996   100   0.85
1997   109   0.92
1998   114   0.97
1999   102   0.87
2000   112   0.95
2001   114   0.97
2002   112   0.95
2003   108   0.92
2004   107   0.91
2005   113   0.96
2006   107   0.90
2007   118   1.00
2008   117   0.99
2009   111   0.94
2010   115   0.97
2011   117   0.99
2012   118   1.00
2013   109   0.92
2014   112   0.95
2015   113   0.96
2016   113   0.96
2017   116   0.99
2018   108   0.91



So, if I am not fooling myself, if I did not make any basic calc errors, etc... June 2019 has sucked up a lot of Sun, and probably is the leading horse in this race. Put in another way : die sea ice, die ! And see you again when MERRA will update.

13
Arctic sea ice / Re: Latest PIOMAS update (July 2019)
« on: July 06, 2019, 08:25:12 AM »
Awesome, Wip, thanks a lot. You received five likes from me, and I wish I could give you more.  :)

14
Arctic sea ice / Re: Latest PIOMAS update (July 2019)
« on: July 06, 2019, 07:59:25 AM »
Thickness map, comparisons with previous years and their diff's.

You certainly want to click these to read the very small fonts (and even then...).

15
Arctic sea ice / Re: 2019 sea ice area and extent data
« on: July 05, 2019, 10:31:15 AM »
magnamentis, I would appreciate it if you refrain from dumping on PIOMAS, ADS-NIPR, etc. These interruptions in daily data reporting are very annoying, but there's no hidden agenda.

16
Arctic sea ice / Re: The 2019 melting season
« on: July 01, 2019, 04:07:04 PM »
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. We may not end up in the top 5 in a sea ice area metric (looking at UH AMSR2 and NSIDC daily data and extrapolating).

Wow, I didn't know you could predict the weather that far out, WD88!

Is it okay if I ban you if you are wrong, come September?  :)

17
Arctic sea ice / Re: The 2019 melting season
« on: June 28, 2019, 06:19:56 PM »
The 12z gfs drops a sizeable but weak low pressure system into the CAB around day 7.

This would finally bring some relief to the basin.


Edit.  It quickly dies in the far Southern CAB.

The earlier gfs runs did this.

But the ensembles kept the dipole going.

We'll see.  The models have been doing this for almost 2 weeks before dropping/curtailing it as we get closer.

18
Arctic sea ice / Re: The 2019 melting season
« on: June 27, 2019, 04:39:16 PM »
The GAC welled up heat stored in layers below the Arctic ocean's surface to melt large quantities of ice. Of course, it takes heat to melt ice. Yes, melting ice is a highly endothermic process. The comment you referred to was incorrect and should be disregarded.

Water is a very unusual liquid, it's extraordinarily strongly hydrogen bonded. It's a liquid at room temperature whereas most other compounds with a similar atomic weight are gaseous. When it freezes it forms covalent bonds, and it expands, and hence it's density goes down. Forming those bonds releases energy. When you break those bonds, you have to add energy. The same applies to the transition from liquid to gas, but this time you have to break all the hydrogen bonds that keep it as a  liquid, and that requires much more energy than the transition from solid to liquid.

I'd recommend reading the wiki on water and ice. There are whole journals dedicated to the research of water. Its fascinating stuff....well, I assume, to the other nerds on this forum....


19
Arctic sea ice / Re: The 2019 melting season
« on: June 26, 2019, 03:39:35 AM »
Is it just me, or does the main pack stretch out (while maintaining near 100% concentration) for many weeks (March & April), as a huge amount of ice is exported and melted in the Atlantic, before finally pulling away from the Russian coast (in early May)? I wonder what are the elastic properties of the pack -- does it actually stretch and contract at constant (max) concentration? -- and how such properties are being affected by the dramatic changes in ice characteristics (thickness, age, density, etc.) in recent years.
The pack does not actually stretch, as it is not cohesive, and ice is not stretchable anyway. What is really happening is that open water is created at the top of the "stretch", and due to the low wintertime temps the open water freezes, thus completing the ice cover and keeping constant max concentration. But this hides the process of effective thinning of the central pack, which this year has been extra-active.
When air temps rise above -10C or thereabouts, the open water has a much harder time keeping up, and eventually the mobile ice is seen to break away from the shore-fast ice.
This process can be seen in animations like this one posted by A-Team.

20
Arctic sea ice / Re: The 2019 melting season
« on: June 26, 2019, 02:00:34 AM »
This bullshit about June not being the most important month is just embarrassing.

Whatever.  Going to look stupid come August.



Also anyone who thinks the ice isn't heading into July in the worst shape we have ever seen it overall is clueless.

I'm sorry for the hard line language but there should be an intellectual integrity here but whatever.

As soon June 15th 2019 THIS YEAR WAS SECOND LOWEST VOLUME ON RECORD.

SINCE JUNE 15TH:

2012 VERSUS 2019.

NOT EVEN CLOSE.


A lot of times BBR can really go nuts with the hyperbole.  Way more than myself and others.  But his claims of 2019 being the worse off are dead on.

The only difference is the Western CAB and parts of the CAA in 2012 got hit good in a warm sunbath by now.

This year the ESS region has taken a bath in the heat.

Half of the Arctic is getting pulverized with solar max insolation and highly anomolous mid level temps.




21
Arctic sea ice / Re: The 2019 melting season
« on: June 26, 2019, 01:41:47 AM »
Check out Nullschool North Pacific SSTA from 4/27-6/21 (in weekly increments)  In addition to the obvious bespoke heat buildup in bearing sea - note the pacific northwest 'Blob' coming online. Most that research the blob's effects say that it is not necessarily a forcing agent on the jet-stream, because jet forcing primarily comes from tropical waters. However, the jury is still out as to the degree that the blob is responsible for maintaining the persistence of ridging/troughing in the wider area.

22
Arctic sea ice / Re: The 2019 melting season
« on: June 24, 2019, 08:32:34 PM »
Oh boy. So sorry, Sterks!  :-[

Not the first time i confuse them. But surely the last time.  :)

23
Arctic sea ice / Re: The 2019 melting season
« on: June 23, 2019, 06:18:47 AM »
I don't think it should be too surprising that we're losing area/extent only at a moderate pace. The Beaufort-Chukchi front opened early, was well retreated and most of the heat has been hitting places where the ice is thicker and that takes time to melt through and break up. The Beaufort sector will still melt out in July (as it did last year in cloudy and cooler conditions) and now it appears there will be a significant portion of the ESS-Laptev and part of the CAB that will follow.

The ess/laptev/chuchki/pacific side CAB has really taken a beating.

If there isn't a break in the ridging the pole could be ice free this September.


24
Arctic sea ice / Re: The 2019 melting season
« on: June 22, 2019, 05:26:54 PM »
Included is a 20 hour loop showing the impressive ridge.  As energy rotates around it, it will go through several anticyclonic wave breaks (evident already).  These often give numerical models difficulty.  As they "break" they generally result in a cyclone downstream, in this case the Beaufort/CAA region.   Again, very hard to predict, and should give anyone pause about buying model runs beyond hour 120, and temper expectations.  Just my two cents.  I'll go back to simple observations of interesting features.

http://rammb-slider.cira.colostate.edu/?sat=jpss&z=1&im=24&ts=1&st=0&et=0&speed=130&motion=loop&map=1&lat=0&opacity%5B0%5D=1&hidden%5B0%5D=0&pause=0&slider=-1&hide_controls=1&mouse_draw=0&follow_feature=0&follow_hide=0&s=rammb-slider&sec=northern_hemisphere&p%5B0%5D=band_m08&x=13964.6669921875&y=16288.22265625

25
Arctic sea ice / Re: The 2019 melting season
« on: June 21, 2019, 10:38:40 PM »
grixm, you may be a noob but you are spot on.

26
Arctic sea ice / Re: The 2019 melting season
« on: June 21, 2019, 09:41:09 AM »
Edit: One thing I've been wondering(and its a bit OT so I'm happy to be directed to another thread) is at what water temperature does sea ice begin to struggle to form  a freezing fresh boundary layer as it melts at the bottom? Ice in Boiling water, or water hot enough for active convection is surely not going to behave that way until substantially cooling the body of water. But what about water that's over 4C, where water is densest. Cooling 4C water to 2C makes it more buoyant, cooling 6C water to 4C has the opposite effect. Does this have any significant effect in diluting and mixing the boundary layer, and exposing the ice to more heat?

I'm not sure how relevant the 4C is, because although the sea ice is fresher than the seawater, it is still salty, and salt water is densest at its freezing point, not at 4C. However, being fresher, the melting sea ice is less dense than the saltier seawater, so in the absence of dynamic processes, it will not sink, preventing mixing.

To what extent it will form a boundary layer is more a question of fluid dynamics, and depends on viscosity and other factors. I'm not qualified to comment on that.

27
Arctic sea ice / Re: The 2019 melting season
« on: June 20, 2019, 05:31:16 PM »
Jim Hunt, pack your swimming trunks! A summer wetsuit as well as the full steamer

Cotty assures me both his back and knee will be AOK by September:


28
Arctic sea ice / Re: The 2019 melting season
« on: June 20, 2019, 04:03:27 PM »
When D1-D6 looks really bad, it's only natural to look beyond, especially when models agree. But always with the caveat that weather forecasts become increasingly unreliable the further out you go.

In other words, it could be even worse!  ;)

29
Arctic sea ice / Re: The 2019 melting season
« on: June 20, 2019, 02:47:53 PM »
Friv, did you really begin your weather career at age 11?? I'm seriously impressed.
BTW, keep up the hyperbole, when it's coming from you it's totally believable. I find your analysis (and language) spot on.

30
Arctic sea ice / Re: The 2019 melting season
« on: June 19, 2019, 11:18:49 PM »
Note that condensation of water releases a huge amount of latent heat, enough to melt 7x its mass of ice. Its the difference between 334 J/g and 2230 J/g. In context the heat capacity for water is 4.186 J/g°C.


31
Arctic sea ice / Re: The 2019 melting season
« on: June 19, 2019, 11:01:42 PM »
A 9 C dewpoint means that a brick on the ground that is 47 degrees F will get wet from water condensing out from the humid air. Now imagine what that warm humid air blowing at sustained 23 miles per hour will do to ice.

Frivolous is right. These are crazy melt conditions on the Siberian side.

And all the heat over Siberia means that there will be a surge of warm river water onto the Siberian shelf. The fast ice will be gone fast.

32
Arctic sea ice / Re: The 2019 melting season
« on: June 18, 2019, 09:55:33 PM »
The 0z ensemble said the same thing as the new 12Z deterministic model. Subsiding warm air continues to create a dome of hot high pressure over the Pacific side of the Arctic and the upper level low continues over the Barents sea in the ECMWF & updated GFS models.

The dome of warm air goes up into the middle stratosphere. That's why it's so persistent and why the models have been getting it right. It's like a mammoth in the living room.

The Laptev bight is going to make it to the pole if this keeps up into July. This is an epic meltdown.


33
Arctic sea ice / Re: The 2019 melting season
« on: June 17, 2019, 10:58:42 PM »
Mercator (model) sea surface temperature (0m), may1-jun16

34
Arctic sea ice / Re: The 2019 melting season
« on: June 15, 2019, 12:49:33 AM »
unihamburg amsr2uhh overlaid onto ascat with 100% ice (normally white) set to transparent. The amsr2 overlay is 70% transparent to allow other features of ascat to show through, notably greenland. It also helps to make the 'weather' over open water less distracting.
Similar to last year the wash of warm weather has revealed fractures in the older ice that were not visible previously.
jun1-13
thanks to A-Team for helpful hints, some of which need further work
https://forum.arctic-sea-ice.net/index.php/topic,2558.msg205561.html#msg205561


35
Arctic sea ice / Re: The 2019 melting season
« on: June 14, 2019, 01:55:19 AM »
I will apply the term 'catastrophe' to the melting of the ice 'up north' without feeling any sense of exaggeration . The catastrophe of the ongoing thaw/melt in the East Siberian and Laptev seas is that it is another of the boxes ticked on the way to a season melt-fest .
 As A-team points out such weather is secondary to the real story of the season .. the unprecedented export of a large part of the multi-year ice to destruction . The export continues over the coming week with the wind blowing from the ESS/Laptev toward Barnetz/Fram . A large part of the remaining older ice will move into the killing zone to make way for the new ice so it can make way for open water .
  One of the results is that much of the colder air in the forecast is in Barnetz and Kara while the Siberian / Pacific side of the Arctic basin is basking in temperatures we in W Europe would appreciate atm.
 Then there was the snow .. strong arguements that extra snow on shore and ice would help delay the melt. No snow on shore or on onshore ice ..
 So I agreed with AM2's anguish at seeing yesterday's SMOS image . Even if it may not accurately reflect reality , it does reflect ongoing melt and the melt is going on and on , as am I . :)  b.c.

36
Arctic sea ice / Re: The 2019 melting season
« on: June 07, 2019, 03:24:04 PM »
The low pressure areas on the Siberian margins will cause large volume losses of the fast ice, but don't expect to see large drops in sea ice extent because lows cause ice dispersion. The warm winds off the continent will take a toll, but that toll will not be immediately evident in the JAXA and NSIDC data.

It will likely not be readily apparent how much damage is being done on the Siberian side for a few weeks.

37
Arctic sea ice / Re: The 2019 melting season
« on: June 05, 2019, 10:37:38 PM »
I hereby allow myself this brief off topic excursion.

Recently Cornwall Council here in sometimes sunny South West England declared a climate emergency. A few days ago there was a lively debate on the topic in the Council chamber.

Today I found myself behind closed doors at the Penryn campus of the University of Exeter where Cornwall's future approach to the climate crisis was discussed:

https://twitter.com/jim_hunt/status/1136230967637696512

My lips are sealed by the Chatham House rules, but I can reveal that the person who advocated "economic growth" was told where to go in no uncertain terms by several people, yours truly included.

The eventual outcome of our deliberations here in Kernow remain uncertain, but it currently seems unlikely that the result will be "green business as usual", or GBAU for short.

38
Arctic sea ice / Re: The 2019 melting season
« on: June 01, 2019, 03:16:25 PM »
Hi res Arctic Basin extent looks as though its heading into uncharted territory.

Meanwhile please wish me luck. I'm just about to head off for the first ever music festival of my entire life! Alice's Wicked Tea Party, rather than Glasto. Fortunately the sun is shining, and I am well prepared!

Many thanks to Jill, manager of Axminster Mole Avon Country Stores for taking my mug shot. (Which is the right way up on my laptop!)

39
Arctic sea ice / Re: The 2018 melting season
« on: August 01, 2018, 03:50:43 AM »
We have had an atmospheric circulation vortex around Greenland for over 3 months that was brought on by the major stratospheric warming in February. That stratospheric warming was caused by the strongest wave driving event, which drove energy upwards from the troposphere to the top of the stratosphere, on record.

High drama in rarefied air

This winter, on February 12, 2018, most of us probably were unaware of the compelling drama unfolding high above the Arctic.  The stratospheric polar vortex, the region of west-to-east winds that circle 6 to 30 miles above the pole, (1) experienced a massive breakdown.  The normally west-to-east winds suddenly slowed and switched direction completely as the stratosphere rapidly warmed more than 50 degrees F in a matter of days (see figure below). .....

Why did this sudden stratospheric warming occur? And more importantly (for blog purposes, at least), why should you care?  Let’s start with the first why. Under the right conditions in winter (2), large atmospheric waves (more than 1000 miles across) travel from the lower atmosphere into the stratosphere. These waves break in the stratosphere, like ocean waves on a beach, transferring a tremendous amount of energy to the atmosphere.

The effect is to slow down the winds of the polar vortex (sometimes splitting it into two smaller vortices).  As the winds slow, air sinks and rapidly warms while the stratospheric air is compressed. This sequence of events is exactly what happened this past February—in fact, we experienced a record-breaking movement of large-scale waves into the stratosphere...




https://www.climate.gov/news-features/blogs/enso/february-and-march-madness-how-winds-miles-above-arctic-may-have-brought

The atmosphere has been destabilized by GHGs. Sudden stratospheric warmings are getting stronger as predicted by climate models. This is affecting summers in the Arctic. The SSW transferred momentum downwards to the tropospheric jet stream, expanding it to record momentum levels in late February and March. After the atmosphere blew its energy in March like a Vegas gambler the jet stream retreated into a vortex around Greenland linked to a track displaced polewards of normal over the Pacific and western north America. Intense high pressure over the subtropical north Atlantic and strong trade winds over the tropics drove heat northwards out of the tropical Atlantic.


40
Arctic sea ice / Re: The 2018 melting season
« on: July 18, 2018, 06:23:55 PM »
This is slowly shaping up to become the billion dollar question. As far as I have seen, no scientists have addressed it as of yet.

Aren't we addressing it? Aren't we all scientists? At least armchair ones ......

*Warmer* winters simple mean less FDD days, so less ice forms. That is visible in ice volume and extent.

I think there is a weak consensus on the Forum that the climate of the Arctic switched to a more Maritime climate sometime during 2015/2016 (look at the winter anomalies in the DMI temps north of 80°C). How long does that take to affect the ice? We have seen two years of this change. Does the Arctic ice/ocean/atmosphere system take 2 years to adjust and reach equilibrium, or 10, or 100? What will that equilibrium look like as we continue to see a warming planet? Are we now eroding a protective halocline that took 5 decades to form or does it reform every year? Is the change to a cloudier Arctic a permanent change because of Anthropogenic global warming? Unfortunately we wont know the answers to these questions for a while, and it is a terrifying and absorbing experiment that we have undertaken.




41
Arctic sea ice / Re: The 2018 melting season
« on: June 19, 2018, 06:48:58 PM »
Please note that we don't have to make assertions based on our personal notions of what's happening in the Arctic. There are science-based models that provide maps, cross sections and animations in real time. It a very good idea to check your personal notions against these models.
http://bulletin.mercator-ocean.fr/en/permalink/PSY4/animation/3/20180501/20180618/3/3

Holy Cow.  That is a terrific site.  Thanks for guiding me farther into the Garden of Earthly Analyses. 

42
Arctic sea ice / Re: The 2018 melting season
« on: June 18, 2018, 10:34:50 PM »
Melt ponds / Kolyma River delta  at ESS coast


43
Arctic sea ice / Re: The 2018 melting season
« on: June 13, 2018, 04:59:19 PM »
How reliable is that information ?

Not reliable at all!

SMOS sea ice thickness is only reliable when its cold. The penetration depth decreases when the ice is getting warm. Therefore UH stops delivering Arctic sea ice thickness products in April and starts only in October.

Look at figure 6 in https://www.the-cryosphere.net/8/997/2014/tc-8-997-2014.pdf

44
Arctic sea ice / Re: The 2018 melting season
« on: June 08, 2018, 04:36:50 PM »
Veli, I am so sorry to learn of Lauren Spence's death. What a loss. My sincere condolences to her husband and to everyone involved in the research.

David Smith-Ferri

45
Arctic sea ice / Re: The 2018 melting season
« on: May 13, 2018, 05:26:20 AM »
edit: the first movie wouldn't display, changed the output encoding( to mpeg4 - which again doesn't display - at least in my firefox/ubuntu setup. I'll leave it for now in case others can see it - it plays fine locally)

Thanks. I was able to download it. Really clear.

46
Arctic sea ice / Re: The 2018 melting season
« on: May 12, 2018, 03:05:13 PM »
The Arctic Climate changed to a Maritime Climate on about December 29th 2015.

Yes, I remember that day well. The sea breeze wafting in...

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