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Wherestheice

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Re: The 2018 melting season
« Reply #2050 on: July 09, 2018, 07:32:24 PM »
Hi Neven!
My concern is that we will enter a time where such conditions will be conducive to ice loss? If we continue to see early opening of peripheral areas and warming of the waters there then any L.P. will act like my old record deck with my toy soldiers stood on it on it when I hit 78rpm!!

We have seen Beaufort go from ice nursery to ice graveyard and I worry that so much more that used to aid the basin will flip 180 under the continued warming forcings ( does it not have to?)

With decreasing floe sizes and open water the mechanical erosion of choppy waters is something the old contiguous pack never used to face.....

I have been with you through the melt seasons of high cloud low temp but I'm not sold on a 'pause' or minor recovery. I think we are just seeing a reorganisation of processes impacting the basin and one of these years the ice will be so poor from the winter re-freeze that any type of summer will take our ice.

Before then I feel we will see one of these 'good for the ice' synoptics devastate the remaining ice!

I agree, tho that might be 5-10 years off. I think If we are gonna see a blue ocean event in the next few years, it’s gonna need to happen because weather patterns similar to 2012, 2007. The ice currently is definitely in a horrible state.... I’m starting to look at the arctic as a big, cold, game of hot potato.
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Tetra

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Re: The 2018 melting season
« Reply #2051 on: July 09, 2018, 07:37:07 PM »
A strange attractor indeed. Mortality Salience artwork here? Any thing will do to distract from confronting the reality of near term death of the cryosphere?

Keep on tooting that horn that no one else believes in! I know you can do it Hyperion!

But seriously? "Near term death of the cyrosphere"?

 ??? ???

I think the Arctic is declining and AGW is picking up and "ice free" (sub 1km squared) is within 10-15 years (Just see the ice level decline from 1979~now), but your idea seems seriously wack in comparison.

No system would decline that fast and that abruptly. Entropy wouldn't allow it. As other people have said further upthread, you have grandiose ideas that you are backing up with an incredibly out of touch reading of the data we have. Buoys salini levels fluctuate because of fresh water, and Smos changes a lot from day to day, colours etc etc.

I bet you'll just call me Tetratroll or something and dismiss me, but as Kermit the frog once said:"you are 100% wrong".

At least this year, because no one else agrees with you. Even the people who believe that we'll see a new record this year or a very low jaxa nsidc reading, don't see a "near term death of the cyrosphere" happening.
« Last Edit: July 09, 2018, 08:01:44 PM by Tetra »

Stephan

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Re: The 2018 melting season
« Reply #2052 on: July 09, 2018, 07:44:59 PM »
The temperature north of 80° is buffered at 0°C. It doesn't give an indication of the amount of heat reaching the ice. [...]
This is why I asked for records of sunshine and cloudiness in the (high) arctic.
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echoughton

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Re: The 2018 melting season
« Reply #2053 on: July 09, 2018, 07:45:54 PM »
No better weather conditions than this for ice retention:
WOW! Beginning to think we could easily not reach 5 million sq K.  8) 8) 8) 8)

Tetra

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Re: The 2018 melting season
« Reply #2054 on: July 09, 2018, 08:05:34 PM »
No better weather conditions than this for ice retention:
WOW! Beginning to think we could easily not reach 5 million sq K.  8) 8) 8) 8)

6 million square kilometres! I'd take that bet!

Jokes aside, I think that although the weather is good for retention, I think we have high dispersion/fragmentation of ice this year. Accounting for no real June cliff (Early July non withstanding) and the lack of century breaks, I think we're primed for a late slush melt of some kind.

Dharma Rupa

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Re: The 2018 melting season
« Reply #2055 on: July 09, 2018, 08:09:42 PM »
I've never seen an ice floe move like that.  ;)

I've seen lots of ice flows move back and forth for no obvious reason.

HapHazard

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Re: The 2018 melting season
« Reply #2056 on: July 09, 2018, 08:34:47 PM »
I've never seen an ice floe move like that.  ;)
Try shaken, not stirred.  ;)
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Thawing Thunder

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Re: The 2018 melting season
« Reply #2057 on: July 09, 2018, 08:48:26 PM »
I agree, tho that might be 5-10 years off. I think If we are gonna see a blue ocean event in the next few years, it’s gonna need to happen because weather patterns similar to 2012, 2007

I think we're primed for a late slush melt of some kind.

The ice would have gone down an endless cliff in the past few years with weather patterns similar to 2012 or 2007 – and statistically we should see similar conditions earlier than in 5-10 years. The slush melt is already happening even with melt retaining weather – this July could show some surprises before ending: There was already an all time compactness low yesterday. Even if it's just a single data point until now, this is exposing strongly the dire state of the ice.

... and there came in another whammy from Wipneus in the Home Brew-threat: "Highest surface melt ratio for the date of all years in the Jaxa/ADS thickness/melting data".

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« Last Edit: July 09, 2018, 08:53:32 PM by Thawing Thunder »
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Hyperion

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Re: The 2018 melting season
« Reply #2058 on: July 09, 2018, 08:55:12 PM »
Now THAT is a dipole.
Super cyclone encompassing the entire Arctic basin and Greenland. High pressure system covering the whole north Atlantic. Heat and moisture being sucked in of off all the continents and the Tropical Atlantic and low fetch high velocity low level winds from Newfoundland to past Svalbard creating huge long period waves aimed at the Atlantic front.
Now THAT is what I call an Arctic death spiral.
Policy: The diversion of NZ aluminum production to build giant space-mirrors to melt the icecaps and destroy the foolish greed-worshiping cities of man. Thereby returning man to the sea, which he should never have left in the first place.
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Ice Shieldz

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Re: The 2018 melting season
« Reply #2059 on: July 09, 2018, 09:32:57 PM »
Now THAT is what I call an Arctic death spiral.

I hope you realize that statements like that are a disservice to this forum. Just as bad as a denier coming in here and making a claims about all this being natural variation and other nonsense. We are all here trying to wrap our minds around how the arctic is responding to severe climate change and to do that we need level heads, clear communication and solid science.

oren

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Re: The 2018 melting season
« Reply #2060 on: July 09, 2018, 09:47:34 PM »
We are all here trying to wrap our minds around how the arctic is responding to severe climate change and to do that we need level heads, clear communication and solid science.
I fully agree.

jdallen

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Re: The 2018 melting season
« Reply #2061 on: July 09, 2018, 09:50:24 PM »
I've never seen an ice floe move like that.  ;)

I've seen lots of ice flows move back and forth for no obvious reason.
If I do, I'll be looking for the outside agency pushing it around ;)

Humor aside, what the pendulum makes me think of is each of the forces/factors in play this melt season - insolation, humidity, sea ice coverage, sea ice quality, sea surface temperature, total system enthalpy, wind and related pack mobility, salinity, air temperature, downwelling long wave radiation, precipitation....  those are just off the top of my head.

And the signals they represent frequently are in complete opposition to one another.  For example, Wipneus just posted this on the area and extent thread - that the Arctic is currently has the highest surface melt ratio for this date:

https://forum.arctic-sea-ice.net/index.php/topic,382.msg162732.html#msg162732

That's at stark odds with Neven's very relevant observation that the current weather conditions otherwise are about as good as it can get for ice preservation.  Forces in opposition.

Each factor is a limb on that pendulum with its own frequency and amplitude.  Summarized, they are the state of the ice.  It's no wonder we have difficulty making precise predictions with so many variables in the mix.
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Neven

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Re: The 2018 melting season
« Reply #2062 on: July 09, 2018, 10:25:18 PM »
That's at stark odds with Neven's very relevant observation that the current weather conditions otherwise are about as good as it can get for ice preservation.  Forces in opposition.

I was actually referring to 6-day ECMWF forecast, not necessarily weather conditions right now, as the big cyclone is still active (at 975 hPa, according to ED, core just off the coast of the CAA), which probably has an effect on the ice and satellite observations.

But nevertheless, I agree with you. Forces in opposition indeed.  :)
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Neven

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Re: The 2018 melting season
« Reply #2063 on: July 09, 2018, 10:28:36 PM »
Here's a post from bbr2314 that was posted in the wrong thread, but I'll let it through here because he makes an effort, posting images, etc. I don't agree with i, though, because it heavily relies on a D10 forecast, which is highly uncertain at this tme:

Today's CMC says you have missed all the signs. The EURO may be inclined to agree. If the GFS comes around, perhaps it's time to start considering this may indeed be worse than 2012?



Talk about a sucker punch to the CAB.



This is far out and it is the CMC but with insolation at all time highs in the peripheral seas this year due to earliest-ever melt out of both Bering, Laptev, and the very high ATL, we have more fuel than ever before (IMO). We have already seen multiple GACs this season and we haven't hit August.



The 850 maps may be blue but the surface is overwhelmingly WET and windy. These are seemingly being driven by both SSTs and the continental heat / smoke plumes. And we have worse conditions for both than any year since 2012 (IMO).

Also: I would say that the projection for a *substantial* Arctic event in the D8-10 period is extra likely due to the impending resolution of Maria. It will transmit a heat pulse that is visible on the modeling and arrives in the Arctic around ^ timeframe. Our most recent GAC was also correlated with a resolving typhoon (and consequent +500MB heat pulse, exacerbated further by latent Siberian heat / -snow anoms, and worsened by the fires and smoke).

If recent trends are any indicator the models will maintain or deepen this until verification (even if it disappears on occasion).
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Neven

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Re: The 2018 melting season
« Reply #2064 on: July 09, 2018, 10:30:05 PM »
And Hyperion has also been put under moderation for the time being (meaning his posts have to be approved by a moderator before they appear).
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Re: The 2018 melting season
« Reply #2065 on: July 09, 2018, 10:50:21 PM »
ok, as i understand everyone is happy with the 15% threshold, point taken and dropped for good.

now i have another question:

when looking at reanalyzer for the last few months, 2m temp anomalies are mostly (not entirely) at or above average, at times even significantly.

at the same time DMI graphs show 2m temps above 80N almost constantly below average.

for better understanding i'd like to know if:

a) they use different averages

b) whet those who know more think about which is more accurate.

reason why i'm asking is that IMO the output is contradictory and i'd certainly like to know on which of the datasets is recommended to rely in case of contradictory data?

Michael Hauber

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Re: The 2018 melting season
« Reply #2066 on: July 09, 2018, 11:18:04 PM »
Hi Neven!
My concern is that we will enter a time where such conditions will be conducive to ice loss? If we continue to see early opening of peripheral areas and warming of the waters there then any L.P. will act like my old record deck with my toy soldiers stood on it on it when I hit 78rpm!!

We have seen Beaufort go from ice nursery to ice graveyard and I worry that so much more that used to aid the basin will flip 180 under the continued warming forcings ( does it not have to?)

With decreasing floe sizes and open water the mechanical erosion of choppy waters is something the old contiguous pack never used to face.....

I have been with you through the melt seasons of high cloud low temp but I'm not sold on a 'pause' or minor recovery. I think we are just seeing a reorganisation of processes impacting the basin and one of these years the ice will be so poor from the winter re-freeze that any type of summer will take our ice.

Before then I feel we will see one of these 'good for the ice' synoptics devastate the remaining ice!

I think 2007 marked a major reorgnisation of the Arctic, and transition from mostly solid multi-year ice to a pack more like Antarctica's dominated by seasonal ice.  Since then I think the only thing that has changed is the globe has continued to warm so gradually more heat impacting the poor quality Arctic ice which has been poor quality since 2007 and in my opinion is not fundamentally changing in nature for the worst (although generally shrinking in extent)

The low pressure in early June was 966hp and considered remarkable by many on this forum and expected to have a significant impact.  I could not identify any substantial impact beyond some scattering of already weak ice in Barents/Kara fringe areas, and protection of the more central ice from melting through cloud cover ad the system weakened.  In contrast an un-remarked cyclone in 2012 was able to cause dramatic scattering of ice in a large swath from Laptev through to Beaufort.  It did occur 2 weeks later in June, so maybe this years early June cyclone was just a bit too early.  Or maybe the ice this year is in overall better condition than it was in 2012.
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Neven

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Re: The 2018 melting season
« Reply #2067 on: July 09, 2018, 11:26:26 PM »
The low pressure in early June was 966hp and considered remarkable by many on this forum and expected to have a significant impact.  I could not identify any substantial impact beyond some scattering of already weak ice in Barents/Kara fringe areas, and protection of the more central ice from melting through cloud cover ad the system weakened.  In contrast an un-remarked cyclone in 2012 was able to cause dramatic scattering of ice in a large swath from Laptev through to Beaufort.  It did occur 2 weeks later in June, so maybe this years early June cyclone was just a bit too early.  Or maybe the ice this year is in overall better condition than it was in 2012.

At how much hPa did that June 2012 cyclone bottom out, how long did it take to de-intensify, and where was the core situated? I don't have time to go through the 2012 ASI updates on the ASIB, and I can't remember this cyclone.
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Re: The 2018 melting season
« Reply #2068 on: July 09, 2018, 11:30:54 PM »
Hey Magnamentis,

I think happy is a VERY strong word with regard to the extent measurement, perhaps best of a lot of medicore options? It's never been perfect but has the advantage of being the one with the best historical baseline, after all comparing say modeled volume to extent very quickly highlights it's limitations. In the past I've very closely followed Extent generally, but this year, it just doesn't feel like it's accurately capturing what's happening so I've taken to following Area / Compactness and volume (so much as is possible) much closer than previous years.

Anyway you've talked about looking at 25% cuttoffs and 35% etc, do you know if anyone has done so, and also done for previous years. I.E. if we compared the day to day "extent" over the past 10 years with a variety of different percentages would we see a any kind of divergence if we graphed 2018 15% vs 35% vs 2013 15% vs 35%? vs 2012 15% vs 35%? if we do get a large divergence it might be a way of quantifying the "slushiness" of the pack in neat way, or possibly early warning of a large melt out...

Liam


Michael Hauber

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Re: The 2018 melting season
« Reply #2069 on: July 09, 2018, 11:32:18 PM »


At how much hPa did that June 2012 cyclone bottom out, how long did it take to de-intensify, and where was the core situated? I don't have time to go through the 2012 ASI updates on the ASIB, and I can't remember this cyclone.

Not sure.  I don't know a good place to look at archived SLP maps, and discovered this low while looking through EOSDIS archives.  The cloud signature only had an obvious cyclone for a day or two, but there was a period of closer to a week that was cloudy.  I'd guess a short lived cyclone of moderate intensity maybe near 980.  A track of weakened ice from Laptev through to Beaufort is clearly visible on EOSDIS shots after its passage and from memory corresponds reasonably well to the systems location.
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Neven

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Re: The 2018 melting season
« Reply #2070 on: July 09, 2018, 11:36:25 PM »
ok, as i understand everyone is happy with the 15% threshold, point taken and dropped for good.

It's not a holy grail. It's just one of many interannual puzzle pieces one has to take into consideration. If extent is normal, while area is going nuts, this is actually more interesting than just area going nuts. A one piece puzzle doesn't tell you much.

Quote
now i have another question:

when looking at reanalyzer for the last few months, 2m temp anomalies are mostly (not entirely) at or above average, at times even significantly.

at the same time DMI graphs show 2m temps above 80N almost constantly below average.

for better understanding i'd like to know if:

a) they use different averages

b) whet those who know more think about which is more accurate.

reason why i'm asking is that IMO the output is contradictory and i'd certainly like to know on which of the datasets is recommended to rely in case of contradictory data?

Yes, probably different averages/baselines. DMI uses ECMWF data, Climate Reanalyzer relies on GFS, I believe. Is DMI 2m SAT?

What is more useful than comparing different data sets, is to compare years with each other within a particular dataset. And then, if you want, you can compare those comparisons between datasets. For example (not necessarily accurate), DMI says 2018 warmer than 2016, CR also says 2018 warmer than 2016. This means: 2018 probably warmer than 2016. Never mind whether DMI says 2018 is much warmer than Climate Reanalyzer says it is (because they obviously do things differently). We're not necessarily interested in perfect accuracy (which model is better), but rather in context (is 2018 warmer/colder than X, and what happened back in X).

This is all 'Stupid question' stuff. Let's go back on-topic again.
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Neven

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Re: The 2018 melting season
« Reply #2071 on: July 09, 2018, 11:51:13 PM »
Not sure.  I don't know a good place to look at archived SLP maps, and discovered this low while looking through EOSDIS archives.

Coincidentally I was looking at this thing I created back in 2014 or 2015, but didn't continue because it was too much work. I'm considering whether I should do a better, simpler version, as I want to get rid of the Webcams page on the ASIG.

The cyclone shows up between June 19th-24th. Doesn't look too remarkable. If it didn't go below 980 hPa, I can understand why it was un-remarked, although I'm pretty sure there's someone back then who remarked it and commented on it somewhere.

Quote
The cloud signature only had an obvious cyclone for a day or two, but there was a period of closer to a week that was cloudy.  I'd guess a short lived cyclone of moderate intensity maybe near 980.  A track of weakened ice from Laptev through to Beaufort is clearly visible on EOSDIS shots after its passage and from memory corresponds reasonably well to the systems location.

Okay, so I checked the ASIB archive, and what do you know, there was a guy called Neven who wrote this in ASI update 5;)

"It looks like we're going to see the exact opposite conditions in the coming week, with that low staying put over the Beaufort Sea and bringing the Beaufort Gyre to a halt. According to melting-season-rules this should slow down SIE and SIA decreases considerably, but at the same time I can't help but wonder what those cyclonic winds are going to do the ice pack."

In the update conclusion I wrote:

"The question now is: Will the conditions that were so conducive to melting have an inertia-like effect on the SIE and SIA numbers? And what is that big low going to do? Will it tear up the ice pack so we get to see the holes we did in the 2010 melting season?"

The answers were posted in ASI update 6, on July 1st 2012:

"As expected the speedy decrease slowed down considerably, but enough was going on all around the Arctic for the 2012 SIE and SIA trend lines to stay close to the bottom years. That big low-pressure system definitely left a mark all over the Arctic, see for instance the holes in the ice pack on this satellite image for June 26th. It is very reminiscent of 2010, but earlier this time around."

And after that a big high took over again. So, high, low, high.



In contrast an un-remarked cyclone in 2012 was able to cause dramatic scattering of ice in a large swath from Laptev through to Beaufort.

Un-remarked cyclone? Tsk tsk, Michael. Tsk tsk.  ;D
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Re: The 2018 melting season
« Reply #2072 on: July 09, 2018, 11:51:31 PM »
i have another question:

when looking at reanalyzer for the last few months, 2m temp anomalies are mostly (not entirely) at or above average, at times even significantly.

at the same time DMI graphs show 2m temps above 80N almost constantly below average.

for better understanding i'd like to know if:

a) they use different averages

b) whet those who know more think about which is more accurate.

reason why i'm asking is that IMO the output is contradictory and i'd certainly like to know on which of the datasets is recommended to rely in case of contradictory data?

   
Surface area above Arctic Circle  million km2    21.046
Surface area above 80+ North in  million km2    3.875
GFs on cci-reanalyzer gives a figure for the temperature anomaly for the Arctic, i.e. surface of the earth North of 66.56o - 21 million km2.
The DMI North of 80o temp is for that small area of under 4 million km2.

There is therefore no inherent contradiction in the data if it differs.

ps: If I ever write it, the book "Environmental Arithmetic" will include this.......
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magnamentis

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Re: The 2018 melting season
« Reply #2073 on: July 09, 2018, 11:56:53 PM »
Hey Magnamentis,

I think happy is a VERY strong word with regard to the extent measurement, perhaps best of a lot of medicore options? It's never been perfect but has the advantage of being the one with the best historical baseline, after all comparing say modeled volume to extent very quickly highlights it's limitations. In the past I've very closely followed Extent generally, but this year, it just doesn't feel like it's accurately capturing what's happening so I've taken to following Area / Compactness and volume (so much as is possible) much closer than previous years.

Anyway you've talked about looking at 25% cuttoffs and 35% etc, do you know if anyone has done so, and also done for previous years. I.E. if we compared the day to day "extent" over the past 10 years with a variety of different percentages would we see a any kind of divergence if we graphed 2018 15% vs 35% vs 2013 15% vs 35%? vs 2012 15% vs 35%? if we do get a large divergence it might be a way of quantifying the "slushiness" of the pack in neat way, or possibly early warning of a large melt out...

Liam

your two points were exactly the ones i was heading at as well:

a) as it seems a 35% threshold would change little in historical measurements because as pointed
.   out only a small area in total fell under that criteria because most of the arctic ocean was a
.   homogeneous ice cover once.

b) my main question was if someone has already tried or would be willing to do the maths
.   i started to play with the numbers  but i'm simply not sufficiently privy with the matter
.   and lack a lot of data, while there are a few guys here who have all the date readily
.   stored on their computers.

with happy i basically meant something along the line "not worth the effort"

i for my part like as accurate as possible stats and numbers but this has nothing to do with
sea-ice only, it's a general thing and has been a major part of my work before retirement.

thanks for the feedbach however, very much appreciated and if most pros think it's good enough
as it is i won't further swim against the main stream.

 8)

magnamentis

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Re: The 2018 melting season
« Reply #2074 on: July 10, 2018, 12:00:07 AM »

Yes, probably different averages/baselines. DMI uses ECMWF data, Climate Reanalyzer relies on GFS, I believe. Is DMI 2m SAT?

What is more useful than comparing different data sets, is to compare years with each other within a particular dataset. And then, if you want, you can compare those comparisons between datasets. For example (not necessarily accurate), DMI says 2018 warmer than 2016, CR also says 2018 warmer than 2016. This means: 2018 probably warmer than 2016. Never mind whether DMI says 2018 is much warmer than Climate Reanalyzer says it is (because they obviously do things differently). We're not necessarily interested in perfect accuracy (which model is better), but rather in context (is 2018 warmer/colder than X, and what happened back in X).

This is all 'Stupid question' stuff. Let's go back on-topic again.

a) thanks

b) stupid question stuff understood

c) remembering the "am i a fool" thread LOL

good night  ;)    :D

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Re: The 2018 melting season
« Reply #2075 on: July 10, 2018, 12:45:49 AM »


Un-remarked cyclone? Tsk tsk, Michael. Tsk tsk.  ;D
oops

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Re: The 2018 melting season
« Reply #2076 on: July 10, 2018, 12:51:34 AM »
And a further point on the current forecast for ideal conditions for ice retention.  It is now 10th of July, and stats show this season back in the pack.  In the past July has been a moment of truth stat-wise for many melt seasons with 2007 bolting from the pack in early July, 2010 and 2011 showing huge potential but beginning big fades in July.  Some seasons make their moves in August with 2012 breaking from the pack, and 2008 making a late charge from mediocrity to challenge 2007.  Time for this season to make a dramatic move is running out quickly.
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bbr2314

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Re: The 2018 melting season
« Reply #2077 on: July 10, 2018, 03:17:37 AM »
I posted this in Wildfires but I think it belongs here because it is kind of ridiculous. The smoke that wafted over the Arctic a few days ago is now descending across Canada and into the Midwest / US Northeast. I am wondering how much this will affect air quality and anticipate some stunning sunsets over the next few days starting on Wednesday.

But, more importantly, I cannot recall something of this magnitude making it this far this intact in memory. I know we sometimes see smoke from fires in Quebec but this plume has managed to stay ridiculously resilient.

I would argue that this is a major testament to the lack of cooling power from the Arctic this year. We will be underneath this Arctic-traversing airmass in NYC starting within 48 hours or so and I can tell you with certainty the forecast is far from frigid (low 80s late this week). If the cryosphere was anywhere near intact the smoke would have probably been dissipated (and such volumes wouldn't have occurred to begin with).

subgeometer

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Re: The 2018 melting season
« Reply #2078 on: July 10, 2018, 04:16:29 AM »
[

As we've seen over several years with DMI's 80N temperature chart, atmospheric temperatures over the CAB are increasingly pulled back towards freezing.  I don't think this is an accident of weather; I suspect its a mechanism driven by increasing open water internal to the pack proper which permits more active direct heat exchange between the ocean at -1.8C and atmosphere. 

Energy is conserved - if the atmosphere is losing more energy to the ocean, the ocean must be warming more - could this  partly explain the slow refreezes we see in autumn?

Edit: fixed to make (some) sense

Jaxa had its first century drop of the summer yesterday(120K). And there is a lot of extent not much more substantial than these swirls in the northern Kara sea, so I think we'll see more soon
« Last Edit: July 10, 2018, 04:55:04 AM by subgeometer »

jdallen

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Re: The 2018 melting season
« Reply #2079 on: July 10, 2018, 07:43:04 AM »
<snippage>
Jaxa had its first century drop of the summer yesterday(120K). And there is a lot of extent not much more substantial than these swirls in the northern Kara sea, so I think we'll see more soon
I think we will see a spate of them over the next week to 10 days.  After that, I think may go back to the pattern we've seen, with sharp drops in area without necessarily comparable drops in extent.
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NeilT

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Re: The 2018 melting season
« Reply #2080 on: July 10, 2018, 10:07:26 AM »
Jaxa had its first century drop of the summer yesterday(120K). And there is a lot of extent not much more substantial than these swirls in the northern Kara sea, so I think we'll see more soon

We saw them in 2012 too.  The interesting thing was that it took the GAC to finally put them away with extensive pumping and mixing.  The lesson being, I believe, that the more it melts the larger the area of fresh water around the ice protecting it from melting more.  The storms deal with that and kill it off, whereas without the storms it hangs around for a very long time.

Which distorts extent figures more.



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F.Tnioli

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Re: The 2018 melting season
« Reply #2081 on: July 10, 2018, 10:15:55 AM »
There is a line of thought in ecology which recognises one important feature of ecosystems: they affect environment in ways which prolong ecosystem's stability. Then comes a point when this compensation is no longer possible, and things collapse. Recently mentioned in the topic algal blooms may have more with weather conditions you just mentioned than we think; possibly, algae affect local climate chemically, much like corals do. What you think? Feasible? Significant?

It's possible that some negative feedback is causing the warm winters and cloudy summers. The ice has been as vulnerable as ever the past three melting seasons, but weather conditions don't come even close to years like 2007 or 2012. It could also be some cycle at play.

But maybe it's just weather. I don't know. I just take it one melting season at a time, and hope scientists are able to make more hay when it comes to long(er)-term processes.

I'm holding out with any definitive statements about this melting season, but as things currently stand, I'd be surprised if the minimum makes the top 3. But you never know. 2016 also had a final sprint.
I don't think warm winters is any kind of a negative feedback; from what i see it's just a consequence of so much heat stored in water (both Arctic and more importantly, - surrounding areas) plus increased cloud cover (which slows down energy radiation into space). I lived in Siberia for 11 years of my life, and winter-time, it was always "mild" frost (some -10...-15C) whenever it's several cloudy days in a row, while clear sky cooled things down to -30...-50sh.
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deconstruct

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Re: The 2018 melting season
« Reply #2082 on: July 10, 2018, 10:47:14 AM »
Now THAT is a dipole.
Super cyclone encompassing the entire Arctic basin and Greenland. High pressure system covering the whole north Atlantic. Heat and moisture being sucked in of off all the continents and the Tropical Atlantic and low fetch high velocity low level winds from Newfoundland to past Svalbard creating huge long period waves aimed at the Atlantic front.
Now THAT is what I call an Arctic death spiral.
That is what I call bullshit.
First, that pattern is not what is known as an Arctic Dipole. The whole Arctic is currently covered by a low, so the winds just flow around on the edge of the Arctic, but there is no significant heat imported into the Arctic. For that, we would actually need a dipole pattern, not something you are just calling that without any knowledge about that term, as it seems.

Second, that is not an Arctic death spiral. What utter nonsense. We will most probably see an average or even above-average (when compared with the last 10 years) sea ice area at the end of the melting season. We have still in many area a above-average snow cover, we have less melt-ponding and preconditioning than the record years, we have no favorable weather for ice melt... I don't know what you are smoking, but please stop doing that.

F.Tnioli

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Re: The 2018 melting season
« Reply #2083 on: July 10, 2018, 11:02:51 AM »
... We will most probably see an average or even above-average (when compared with the last 10 years) sea ice area at the end of the melting season. We have still in many area a above-average snow cover, we have less melt-ponding and preconditioning than the record years, we have no favorable weather for ice melt... I don't know what you are smoking, but please stop doing that.
1st, you're being rude ("bullshit" and "smoking" parts). Please, stop being rude. Proper science can never be done when people attack each other. 2nd, few posts above even Neven admitted that this season may still end up in top-3 in terms of minimum annual ASI cover, - and i agree. Therefore, your "we will most probably see an average or even above-average" is over-confident to say the least. If Hyperion is going too far one direction, then you're going too far the other.
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Quantum

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Re: The 2018 melting season
« Reply #2084 on: July 10, 2018, 11:52:16 AM »
Didn't Neven suggest that to end up in the top 3 we would need the weather to change though? Can someone explain how what we have now is detrimental to the arctic? The GAC that came in August 2012 affected already fragile ice at the end of August and even then wasn't the primary reason 2012 was record breaking (it was already preconditioned by conditions during July). At the moment we have a cyclone over the Beaufort which by all accounts seems to be in the best condition (at least as far as MODIS presentation goes) since 2014 and we aren't even half way through July yet. What's more the cyclone is forecast to weaken and cover the entire arctic. Seems more like a 2013 PAC than a 2012 GAC to me. In my humble view I'd suggest its far more likely this year will end above average for the 2010s and above the linear trendline unless the weather changes. But even if the weather does change it will have to do so soon because in a few weeks time the sensitivity to weather conditions is going to be much lower as bottom melt starts to dominate. 

Jim Pettit

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Re: The 2018 melting season
« Reply #2085 on: July 10, 2018, 12:31:10 PM »
Jaxa had its first century drop of the summer yesterday(120K). And there is a lot of extent not much more substantial than these swirls in the northern Kara sea, so I think we'll see more soon

That may be--but JAXA saw its smallest decrease in three weeks yesterday. The drop of just 25k is nearly 71k smaller than the 2008-2017 average loss for the day; that's the greatest departure from that average since early March.

The largest JAXA daily decreases normally occur from the last week of June through the second week of July. Over the last ten years, the average daily decrease for the last two weeks--June 26 through July 9--has been 90.4k. Over that same period this year, JAXA has averaged a drop of just 69k.

IOW: 'tis a very, very slow year for extent decrease.

Alexander555

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Re: The 2018 melting season
« Reply #2086 on: July 10, 2018, 12:38:16 PM »
Now THAT is a dipole.
Super cyclone encompassing the entire Arctic basin and Greenland. High pressure system covering the whole north Atlantic. Heat and moisture being sucked in of off all the continents and the Tropical Atlantic and low fetch high velocity low level winds from Newfoundland to past Svalbard creating huge long period waves aimed at the Atlantic front.
Now THAT is what I call an Arctic death spiral.
That is what I call bullshit.
First, that pattern is not what is known as an Arctic Dipole. The whole Arctic is currently covered by a low, so the winds just flow around on the edge of the Arctic, but there is no significant heat imported into the Arctic. For that, we would actually need a dipole pattern, not something you are just calling that without any knowledge about that term, as it seems.

Second, that is not an Arctic death spiral. What utter nonsense. We will most probably see an average or even above-average (when compared with the last 10 years) sea ice area at the end of the melting season. We have still in many area a above-average snow cover, we have less melt-ponding and preconditioning than the record years, we have no favorable weather for ice melt... I don't know what you are smoking, but please stop doing that.

And what about the heat that is imported over land, on the Siberian side. They had some rain, and there are plenty big and small rivers. And even during the night the temperature did not drop below 10 degree C at many places and 20 + degree C during the day. And the difference in hight is probably not so much. So it will flow slowly, it has time to warm up. But i have no idea about the volumes, so i don't know if it's significant. How much rain do they have in Siberia ?

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Re: The 2018 melting season
« Reply #2087 on: July 10, 2018, 02:20:58 PM »
Interesting that Andrew Slater's algorithm is now predicting a strong melt season: extent (though if I recall correctly it is their own definition and not exactly equivalent to the other extent definitions we see results from) to drop to 4.56 million square kilometers already by 29 August 2018.

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Re: The 2018 melting season
« Reply #2088 on: July 10, 2018, 02:23:02 PM »
Dr David Schröder also sent me the melt pond fraction map for June, showing a lot more melt ponding. He has adjusted his SIPN prediction accordingly (downwards). I plan on writing an extensive blog post on May and June this weekend, and will post the Schröder maps.
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subgeometer

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Re: The 2018 melting season
« Reply #2089 on: July 10, 2018, 02:36:49 PM »
Lows acting like cogs drew in massive amounts of atmospheric heat over the past weeks. The low forecast now is kinder as cold deveops over most of the basin at 850mb for the next week but all the peripheral seas - Laptev, ESS , Chukchi and Beaufort are all subject to further warm intrusions from the south, while the Kara and Hudson Bay will be basking in heat, so they should melt out soon. The area a low can protect has maybe shrunk a bit

ECMWF sees that cool airmass being blown asunder in a week or so by another influx, this time frtom the Atlantic, who knows, but it would not surprise.

Glue ice is starting to melon t out in the southern Beaufort, and after the mini-GAC small gaps are appearing distressed ice as far north as 81N on that side. Blue grey and brown discoloration is visible from Svalbard around the whole periphery and far into the pack, so we may be in for some drama yet even if this is not THE year


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Re: The 2018 melting season
« Reply #2090 on: July 10, 2018, 03:48:32 PM »
Again the blue areas made progress in the enhanced graph. The ice could get again that arrow-like structure pointing towards the Atlantic as it did in 2015 before the GAC hit. The persistence of the bluish areas hints toward a continuous melt there and not to some capricious coloring due to weather patterns.
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Re: The 2018 melting season
« Reply #2091 on: July 10, 2018, 04:05:32 PM »
Neven's 'compactness' graph in the 2018 data thread reminds me of TT's 'it doesn't look bad now, but just wait' [semi-quote from memory of some things written a few days ago].  I think the 'quality' of ice in several parts of the Arctic has degenerated to the point that melting causes the ice to spread out more [many fewer 'big block' sort of floes, more weak 'glue ice'], keeping extent high. 

Derived mostly from watching the Lincoln Sea and Nares Strait ice, I think SIA is also bloated by spread-out ice, at the expense of thickness.  This interpretation, coupled with Neven's compactness graph, makes me a believer in Slater's (algorithm) currently projected extent cliff.  Of course, we have seen seasons where the 'poof' was preempted by an early freeze or exacerbated by a GAC.  Time will tell.

Although I no longer expect a record low extent this year, I won't be surprised by a 2nd place.  I would be surprised by an 8th place or more.
« Last Edit: July 10, 2018, 06:01:42 PM by Tor Bejnar »
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deconstruct

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Re: The 2018 melting season
« Reply #2092 on: July 10, 2018, 04:23:42 PM »
1st, you're being rude ("bullshit" and "smoking" parts). Please, stop being rude. Proper science can never be done when people attack each other. 2nd, few posts above even Neven admitted that this season may still end up in top-3 in terms of minimum annual ASI cover, - and i agree. Therefore, your "we will most probably see an average or even above-average" is over-confident to say the least. If Hyperion is going too far one direction, then you're going too far the other.
On the "smoking" part: Point taken.
But when something is clearly nonsense/bullshit/[insert-word-of-your-liking], it is not rude to call it that IMO, its just the truth. You could also say it is plain wrong, but that is essentially the same. And that it is wrong, was said multiple times, and I would say "nonsense", "bintroll" or "willfully ignorant" isn't the most polite thing either. In Germany there is a saying "Wie man in den Wald hineinruft, so schallt es heraus", which would be literally translated "As you shout into the woods, so it shouts back". I guess in English the equivalent would be something like "What goes around, comes around" or "Yo reap what you sow".

But back on the actual topic:
I said that this year will end up probably average or above average in respect to the last 10 years. The last 10 years had an average daily minimum extent of 4.5 million km² with a standard deviation of +/- 0.5 mio km². So "average" would be 4-5 million km². To get into the top 3, it is enough to end up below 4.1 million, which is even within the standard deviation, so an "average" year can even make it to the top-3, when it is on the lower end of the average.

So I'm not disputing what Neven had said, but for this year to reach the top 3, the remaining weather would have to be absolutely favorable for melting, so I would say it is not very likely. Much more likely is however, that the year may end up around 5 Mio km² or above, as you might just need average weather for that.

In any case: This year will not be the end of Arctic ice or a prime example for the "Artice death spiral". That is just nonsense.

deconstruct

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Re: The 2018 melting season
« Reply #2093 on: July 10, 2018, 04:46:27 PM »
And what about the heat that is imported over land, on the Siberian side. They had some rain, and there are plenty big and small rivers. And even during the night the temperature did not drop below 10 degree C at many places and 20 + degree C during the day. And the difference in hight is probably not so much. So it will flow slowly, it has time to warm up. But i have no idea about the volumes, so i don't know if it's significant. How much rain do they have in Siberia ?
First of all, you would have to show, that this years temperatures in Siberia are actually significantly higher than what we typically see. I would guess that they are not. Sure, June was hot in many regions in Siberia (but it is hot there in many years), but over the last 3 months, the temperatures were not extraordinary:


Second, snow cover was above average in siberia and even now (despite the hot days in june) there is still more snow cover or ice-covered lakes there as compared e.g. with 2016. And river temperature can very well be below average when there is more snow to melt, even if air temperature is above average.

Overall, I don't think that the water temperature from Siberian rivers is so much higher than in other years, that this will make a difference in respect to September minimum sea ice extent.

If you look at all the coastal land around the Arctic - regardless if it is in the CAA, on the Alaskan north slope or on the Siberian side - you see, that the lakes are longer frozen e.g. as compared to 2016 and that the ground is/was longer snow covered than compared to 2016. That tells me, that there was a) more snow than 2016 and/or b) lower temperatures as in 2016. In any case that will not help getting a lower sea ice minimum.
« Last Edit: July 10, 2018, 04:52:09 PM by deconstruct »

Richard Rathbone

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Re: The 2018 melting season
« Reply #2094 on: July 10, 2018, 05:10:28 PM »
Dr David Schröder also sent me the melt pond fraction map for June, showing a lot more melt ponding. He has adjusted his SIPN prediction accordingly (downwards). I plan on writing an extensive blog post on May and June this weekend, and will post the Schröder maps.

Any chance of a preview on the SIPN numbers? I was about to write up a projection based on his May SIPN for my predictions challenge and arm wave it down 1 bin from PIOMAS and NSIDC area anomalies in June, but having his actual number before the closing date would be better, since the Schroeder melt pond analysis is my preferred metric for the July polls.

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Re: The 2018 melting season
« Reply #2095 on: July 10, 2018, 05:11:50 PM »
It's 4.7 +/- 0.5 million km2.
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Re: The 2018 melting season
« Reply #2096 on: July 10, 2018, 05:16:13 PM »
It's 4.7 +/- 0.5 million km2.

Thanks.

Is that +- 0.5 a standard deviation or a confidence range? It was a 0.5 standard deviation from May data, and I'd expect it to be tighter from June data.

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Re: The 2018 melting season
« Reply #2097 on: July 10, 2018, 05:18:51 PM »
Given the compactness figures 2018 is about 8% below last year, so without any further melting a reversion to last year's value would result in a drop of extent by ~500,000 km^2!  There's a lot that could still happen, the area drop in the Central Arctic which is ongoing causes me concern.

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Re: The 2018 melting season
« Reply #2098 on: July 10, 2018, 05:27:38 PM »
Given the compactness figures 2018 is about 8% below last year, so without any further melting a reversion to last year's value would result in a drop of extent by ~500,000 km^2!  There's a lot that could still happen, the area drop in the Central Arctic which is ongoing causes me concern.

I second that without crying wolf. The Arctic seems to be weaker by each year as also the new compactness record for the date is showing. But I think there must happen something extraordinary to kick off a dramatic melt that would make that totally obvious.
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Re: The 2018 melting season
« Reply #2099 on: July 10, 2018, 07:36:10 PM »

First of all, you would have to show, that this years temperatures in Siberia are actually significantly higher than what we typically see.

Actually, your graph shows exactly that. Half of siberia had  temps 2-3 C above average