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Messages - Michael Hauber

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101
Arctic sea ice / Re: The 2018 melting season
« on: August 23, 2018, 01:30:18 AM »

In very short.  YES solar fluctuation does have an impact.  NO, that impact is not significant, but it is there and it is measurable.

Bordering on overly pedantic quibbling over definitions, and hopefully not crossing the line: I'd say anything there and measurable is significant.  For instance Collins dictionary definition

Quote
A significant amount or effect is large enough to be important or affect a situation to a noticeable degree.

Perhaps it depends on context, if you are trying to carefully analyse climate and build a model of everything going on then solar input is big enough that it should be included in the model (and  has been in at least some that I know of), and is therefore significant.  If you want to explain what is currently happening with climate to a layman who doesn't want to get bogged down in all the details than solar influence is small enough to be ignored and so not significant.

edit:  And a big issue with solar is possible regional changes brought about by circulation changes.  For instance part of the little ice age issue is that the cooling was strongest in regions not far from the Arctic, tied into changes to Atlantic Oscillation that may be linked to solar activity.  Quick google search finds this paper.  It is possible that low solar activity may lead to reductions in sea ice due to regional cooling in Europe etc balanced partly by regional warming in Arctic.

102
Arctic sea ice / Re: The 2018 melting season
« on: August 21, 2018, 01:40:22 AM »

How? It's in a distorted cylinder projection, doesn't go above 80ºN and is unreadable/unreliable there, plus it would have to be cut down to comparable ice covers which isn't practical without having the data in polar stereographic projection. Are the grid cells really of adequate resolution for the Arctic seas and islands -- I can barely make out Greenland.

[/quote]

How?  By opening your eyes and having a look.  It might not be as pretty or as easy to read as the newer charts, but the comparison is still very obvious that 2007 had a lot more warm ocean surface than this year.  Stands to reason as 2007 started with substantial amounts of thick multi-year ice, this year followed on from the warmest winter ever, and the multi-year ice basically gone.  But conditions in 2007 melted more ice than the conditions this year.

103
Arctic sea ice / Re: The 2018 melting season
« on: August 20, 2018, 11:13:31 PM »
SSTs look quite tame to me.  Compare current to 2007

In 2007 the warm ocean seemed to retard freeze for a few weeks with -ve anomalies on area dropping quite a lot (nearly 1m sq km from memory) in the few weeks after minimum.  After that freeze went rapidly and made up most of the lost ground within a few more weeks.

104
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: August 17, 2018, 11:22:17 PM »
Putting out the data on a daily basis is interesting, and despite the odd offhand comments to the contrary, most people seem to feel it has value.

But now as the season comes to an end, the question the data asks me is - "what was the story this melting season?" Of course the story ain't over yet but using graphs I would like to tell - as I see it - the story so far. I see it as a tale of two ends - the Pacific and the Atlantic, and may take some time as I look through the data.

At the beginning I thought(as did many others?) it was going to be all about the Pacific end. NOAA / NASA said it was that end that had the highest temperature anomalies (for several years), and low and behold, the Bering Sea Ice collapsed in front of our eyes.

I think a lot of people did expect big things on the Pacific side.  One thing though is that PIOMAS data at end of May showed that Siberia/Laptev ice was about the thickest of any recent years, with Beaufort being more typical and ice towards Greenland being on the thin side.  In some ways I thought there was potential for an all or nothing year this year - a savage melt season would have still taken out the thicker ice towards Russia, and attacked the thinner ice towards Greenland.  But an average melt season, or possibly poor melt season with slow start and stronger melt weather in August, allowed lots of this thicker ice to survive (so far).

105
Arctic sea ice / Re: The 2018 melting season
« on: August 09, 2018, 10:58:12 PM »
Seems that the big high pressure dome over the Laptev side of the Arctic is now starting to wind down.  No sign of massive ice loss as predicted by some of the more exciteable posters in this thread.  Models seem to want to build a significant low so we'll see what the heat and stir method can achieve.  I do think the ice in that area is on the strong side of what can be expected in this age of ice everywhere weaker, and the results might be similar to the recent Beaufort plunge - moving up through the pack a bit, but by no means leaving it in the dust.  We are getting into the shoulder season with strong but definitely declining solar input so the slow down due to cloudiness won't be as significant as for low pressure systems earlier in this season.

106
But this is OT as to the CAB surface going 'black' in the winter due to climate change.

True, but my point is that people are proclaiming Truth when it isn't even yet clear they are working with a viable Theory.

I'd like to hear suggested mechanisms, not obeyance to the Great Modelling Gods.

Strawman.  Models are not truth, no one has claimed that they are.

I'd say anyone who think that Arctic ice can disappear this century during winter lacks a viable theory and the challenge is to come up with a better method than the models of predicting future sea ice conditions.

107

I'm just strongly opposed to using current models to project "centuries" given that we can't really claim to even know what's going to happen with the seasonally ice free arctic in the decades after. And as a result, how could the models do any better?

Multi-century model projections are obviously problematic.  Is there a better alternative?  (I don't think so)  Or do we just avoid talking about the issue altogether?

108

Yes, of course, if it remains at -20°C and that the AML survives.

There is evidence that you start to get 1000m convection cells forming when the AML breaks down, say because of the lack of summer ice, and that would certainly cause enough heat to be transported to the cloudy dark rainy Arctic to keep it ice free.

https://link.springer.com/article/10.1007/s00382-017-3849-9

Reduce the FDD days enough, add enough heat in the atmosphere and the ocean and add convection to the top 1000m of the Arctic? Perhaps that would be enough heat to keep it ice free during the long cold Arctic night. 

How long will that take?.  Also consider shallow shelves on Laptev  Convection and warm currents might maintain ice free at north pole right through winter, but Laptev being shallow and protected from warm currents, and adjacent to cold land mass will take longer.  Consider current situation in Antarctica and north Pacific.  What is AML?  Something to do with stratification of Arctic?  Antarctica and North Pacific don't have this and manage to get ice in winter.  Just needs to be cold enough, so it depends on how long it stays cold enough.  Judging by model projections I'd say best guess is it will stay cold enough for centuries.

109
How many centuries does paleontology tell us it took to go ice free last time the earth was this warm and warming at this rate?

How warm was it last time paleontology told us it was ice free in winter?  I could look it up myself, but maybe those who want to appeal to paleontology should do the work?  Also +x degrees at equilibrium will be different from +x degrees while rapidly warming.  During rapid warming the land warms significantly faster than the ocean surface, and the ocean surface warms faster than the subsurface.  Both will make a big difference as to whether the ocean can resist several months of winter darkness/cold without freezing.  Arctic ocean surface might be an exception, but moreso in summer.  Outside Arctic is still going to warm slower than land and make a difference to how much heat is brought in by currents.

110


Even volume? Even volume? You are aware the world does occur in 3D, right? How could you prefer extent more than volume?

I think I explained it just fine in my last post.  Is there some part of it you didn't understand.

There is a place for it, but the top indicator has to be volume...cuz it is, like,  the actual amount. Takes a certain amount of energy to melt a certain volume of ice.

Winter maximum isn't about melting ice, it is about conditions being cold enough for sea water to freeeze.

Speaking of madness...saying "well this is what is going to happen cuz a  few models say so..." is effectively like pontificating about what would happen in a zombie outbreak cuz thats what happened in Fortnite or Call of Duty waves. How good do you believe the models are? Can any models tell me what the weather will be like in a month?

Climate deniers don't like what the models say so run exactly the same argument.  Seems you don't like what the models are saying and so are running exactly the same argument.  This is a science based forum and not Watts Up with That.  The models are certainly imperfect, but whats a better method for predicting the future? 

111

How does the model maintain the cold halocline layer despite the lack of sea ice cover?

You're talking about a model of arctic sea ice decline, not a model of a blue ocean event.  We have no clue what that looks like, but the hypotheses floating around suggest papers in the next couple of years that begin to test the subject.  Models of arctic sea ice disappearance may be able to be sourced in such discussions right about the time it's happening right in front of our eyes.

I'm sure the model programmed by Arctic experts does a better job of predicting the influence of the cold halocline on sea ice than the guesses of members of this forum.

112
Ice free in winter is not going to happen in the next few centuries.


Ice free in winter already began happening in 1900.

My statement is probably going to end up being closer to reality than Michael's.

Based on what evidence?  Even the models that overestimate current ice loss do not get below 10m sq km of ice in winter by the end of this century.  I'd trust models over extrapolating a trend.  And extrapolating extent over extrapolating volume.  It is not how thick the ice is that determines ice free winter - it is the extent of ocean that is cold enough in the coldest part of winter to support the formation of ice.  Even extrapolating volume gives us another century until ice free winter.

113
Ice free in winter is not going to happen in the next few centuries.


114
Arctic sea ice / Re: The 2018 melting season
« on: August 04, 2018, 12:47:30 AM »
Quote
Even after a summer BOE, ice will still form in the Arctic during the dark, polar winter for many decades
So, this being merely 2018, it surely follows that Svalbard-FJL-SZ corridor froze over this winter?

Except it never came close. And this year was only a continuation of a long-term regional trend, not a variational swing attributable to unusual weather, cycle, oscillation, phase or teleconnection event.


Big difference between this region with deep water, and directly in the path of one of the warm currents from the Atlantic.  Compare to say Laptev with shallow shelfs and no direct exposure to warm Atlantic waters.  I note also that in this corridor the edge of the ice is pretty much in the same spot as it was at maximum.  Not exactly representative of general Arctic sea ice behaviour.

115
Arctic sea ice / Re: 2018 sea ice area and extent data
« on: August 02, 2018, 01:33:09 AM »
Massive drop in NSIDC SIE (253K, following 211K yesterday), second lowest on record now, causing massive uptick in compactness. Glitch or real?

I don't think the conditions in the Arctic were suddenly so much worse than the previous few days so at to more than double the rate of melt. 

If sensor variations can cause ice to be measured at 50k more or less on the day, then the sensors are working well, and measuring ice to about 1% accuracy (when area/extent is near 5m).  But then if daily losses are near 100k, and sensors switch from an overestimate of 50k to an underestimate of 50k, then sensors are reporting twice as much ice lost for the day as actually occurred.

116
Arctic sea ice / Re: When will the Arctic Go Ice Free?
« on: August 02, 2018, 01:02:39 AM »

If we are currently experiencing the effects of warming from CO2 emissions up to 2008 (to slightly simply things), then 380 ppm should correspond to about 1C temperature rise. SO SO SO SO SO WRONG. Last time concentrations were that high was a few million years ago and the temperature was significantly higher, sea level was significantly higher, and there wasn't any significant ice in the northern hemisphere. More recently, the co2 to temperature correlation would suggest at least 5C of warming from a 280 to 380 increase.

The graph you supplied is for temperature at Vostok (Antarctica) not global temps.  Also note that the primary temperature driver over this period was orbital changes - and then the temp changes drove CO2, and Co2 provided an additional feedback to warming.  So 5C in Antarctica is reduced by about half to get a global value, and then further reduced by however much of the warming was caused by orbital changes.

117
Arctic sea ice / Re: The 2018 melting season
« on: August 01, 2018, 12:36:01 AM »
Towards Siberia  looking far more solid than same date 2012

118
Arctic sea ice / Re: The 2018 melting season
« on: July 28, 2018, 10:57:50 PM »
I think some of the change in ice conditions on the Pacific is due to changes in cloudiness/melt ponds etc.  Still some serious melt going on though.

119
Arctic sea ice / Re: The 2018 melting season
« on: July 27, 2018, 11:03:13 PM »
Beaufort and Chukchi is definitely in bad shape, comparable to 2012 and about to get slaughtered.  Siberian (western half) and Laptev is much better and won't lose so much.  I don't think we will seriously challenge 2012.

120
Consequences / Re: Conservative Scientists & its Consequences
« on: July 25, 2018, 11:16:02 PM »
To guestimate some figures, at equilibrium net anthropogenic climate forcing might be 4.5, temperature change 3, total aerosol forcing -1.  In that case aerosol cooling would work out at -0.75. 

Your argument fails to notice the difference between top of atmosphere radiation imbalance and net forcing.  This difference is change in long wave radiation in response to change in temperature.

121
Consequences / Re: Conservative Scientists & its Consequences
« on: July 24, 2018, 11:29:42 PM »
That paper provides no evidence of a higher aerosol forcing.  It only looks at what the implications of a higher aerosol forcing for climate sensitivity.  To quote from the paper

Quote
The range of aerosol forcings predicted by ‘forward’ models, using our best knowledge on the atmospheric aerosol burden and its climate effects, is vast, from 0 to 4.4 Wm2

IPCC 5 aerosol forcing is stated as -1.9 to  0.1 w/m2.  Total anthropogenic net forcing is stated as 1.1 to 3.3 2/m2.  A net forcing of 1.1, and net aerosol forcing of -1.9, a current warming of 1C would imply that aerosols are currently causing about 2C of cooling.  Probably also corresponds to a climate sensitivity at the upper end, but half that if climate sensitivity is moderate.  Therefore a range of 0.5 to 1C for aerosol cooling is not at all inconsistent with the IPCC range.

122
Consequences / Re: Conservative Scientists & its Consequences
« on: July 23, 2018, 11:14:30 PM »


Because all the models are wrong - they are useful not perfection. Close enough is often good enough.


Yes so we could certainly end up with more warming in the future than forecast.  Or we could end up with less warming than predicted. 

PS When will the 0.5C supposedly already built into the climate system but not yet showing up as observed surface / ocean Temperature anomalies going to appear and how fast will it appear? Is this already detailed in past and future modelling efforts?


How else could we possibly measure the warming built into the climate system but with models?

123
Consequences / Re: Conservative Scientists & its Consequences
« on: July 23, 2018, 04:12:36 AM »



Quote
If I am correct, the SO2 impact of the models is understating their cooling impact by much more than the 0.7C (median estimate) from this recent study (but still much more than the CMIP5 model mean):  https://nationalpost.com/news/world/scrubbing-aerosol-particles-from-the-atmosphere-a-faustian-bargain-study-finds

Thats not a study but a news article.  The first link finds a study that runs some climate models and finds that removing aerosols accounts for 0.5 to 1 degree of warming.  It presents zero evidence that the models are understating the amount of cooling due to aerosols.

and, of course, you posit that historic performance of models indicates that their projections of future warming are not understating the likely reality even though we already know that they do not include permafrost emissions, severely understate the non-permafrost land-based carbon cycle feedbacks, understate cloud regime changes, do not include ocean aerosol reductions under future ocean acidification and understate both the speed and impact of Arctic Sea ice loss (especially under a rapid SO2 emissions reduction projection).

I think that you are being silly.

Permafrost has been melting for the last 40 years.  Land-based carbon cycle feedbacks have been occuring for the last 40 years.  Cloud regimes have been changing for the last 40 years.  Aerosols have been changing due to ocean acidification for 40 years.  The Arctic ice has been melting for 40 years.

If these factors are going to cause the temperature to warm faster than the models, then why have they not done so for the last 40 years?

124
Consequences / Re: Conservative Scientists & its Consequences
« on: July 21, 2018, 08:38:12 AM »


But what about the fact that the models are already over predicting the warming rate ...

Are they?


Yes, but only by a quite small amount, which shows up quite well in your last graph.  The argument here is not that the models are overpredicting observed warming by a significant amount so as to throw doubt on model performance.  The argument is that as the models are overpredicting observed warming, then claiming that they are overly conservative is an extraordinary claim requiring extraordinary evidence.

Nonetheless: it shows the models beeing bang on the money.

Agree, and i think claims they are overly conservative and need to be revised upwards are silly.

125
Consequences / Re: Conservative Scientists & its Consequences
« on: July 21, 2018, 12:29:18 AM »

With regard to michael's comment, the cloud forcing that is now being defined (which we have already shown in this thread through multiple lines of evidence to be understated by the climate models) and it shows what we have already suspected, with an upper bound from this impact only of ~3.7C ECS.  However, our projections are not based on historical observational constraints but rather the impacts under future warming conditions, especially under the regime of much lower tropical SO2 atmospheric loading, leading to even fewer cloud regimes and greater expansion of the Hadley Cell.


Yes the models that model clouds better have a higher ECS.  I already acknowledged that.  But what about the fact that the models are already over predicting the warming rate, and increasing cloud feedbacks would presumably make that worse?  Do you have a response to that issue?  Or is your response that 'projections are not based on observational constraints'.  Is this a fancy way of saying 'We are ignoring reality'?

126
Consequences / Re: Global Surface Air Temperatures
« on: July 20, 2018, 07:49:35 AM »

It's well established that the lag time is really between 2 and 5 months (papers galore on this topic). I was being generous/conservative by saying 2-3 months, just to emphasize the point.


Yes typical ENSO lag is something like 2 to 5 months.  But it varies substantially on at least a seasonal basis.  Development of nino 3.4 is often relatively steady from SH Autumn or winter, and typically peaks in Dec or Jan, and then decays reasonably steadily until next SH Autumn or Winter.  In contrast global temperature shows zero response until October -lots of lag- , but then grows very quickly through Nov and Dec to peak at January - almost zero lag.  It then drops a little early in the year but holds until May or June and then drops quite quickly so that September or October are pretty close to 0 ENSO influence in most years.

And from the data I've looked at I suspect bigger lag for stronger events, with 97/98 having the slowest and largest temperature response I've seen, and a couple short/small events below threshold el nino/la nina threshold coinciding with temp response at no noticeable lag.  It does makes sense when you consider that inertia likely plays a role in the lag.  The bigger the ENSO event, the longer it takes the climate to return to normal.

127
Consequences / Re: Global Surface Air Temperatures
« on: July 20, 2018, 04:25:26 AM »

We're coming off a moderate La Nina. Atmospheric temperature response lags ENSO by several months (at least 2-3 months generally), so the GMSTs we have now still have Nina influence (see 2015 for example, where significant GMST increases didn't really start until September of that year).

This year and last year were dominated by a strong Walker Cell and were ENSO negative:

2016   2.5   2.2   1.7   1.0   0.5   0.0   -0.3   -0.6   -0.7   -0.7   -0.7   -0.6
2017   -0.3   -0.1   0.1   0.3   0.4   0.4   0.2   -0.1   -0.4   -0.7   -0.9   -1.0
2018   -0.9   -0.8   -0.6   -0.4   -0.1

The NCEP threshold for La Nina was met, but not by a large amount.  The BOM threshold for La Nina was not met.  While the BOM and NCEP definitions of threshold are different the main difference was that the measurement of nino 3.4 recorded by BOM were not as cool.  I would call last year borderline cool neutral/weak La Nina and not moderate. 

During 2000/2001 nino 3.4 values were cooler, and for longer, and GISS temps during 2001 were closer to the el nino dominated 2002-2007 years than they were to the clearly La Nina dominated 1999 and 2000 years.

Lags are highly variable, and may be longer for strong events and shorter for weak events.  Given the weakness of the recent event, and the fact we are now well onto the way to warm ENSO values I think current temperatures more likely reflect a neutral ENSO influence.

128
Consequences / Re: Conservative Scientists & its Consequences
« on: July 20, 2018, 01:21:39 AM »
Dessler & Forster.  Mode 2.9k, median 3.3k.  Quite consistent with IPCC.
Paynter et al.  3.3k and 4.8k are two individual models.  CMIP5 models range from 2 to 4.5, so pretty much in the range.  However both models are found to be one degree higher than the corresponding value quoted for that model by IPCC due to a different method of defining ECS.
Caldwell et al.  models which match clouds the best have a high sensitivity(in this case 3.4 to 5.2)
Qu et al - again models which match clouds the best have a high sensitivity.  Last sentence from abstract - 'any proposed ECS constraint should not be taken at face value since other factors influencing ECS besides shortwave cloud feedback could be systematically biased in the models.'
Frey & Kay - again improving the accuracy of cloud feedbacks results in a model with a higher sensitivity.


It should be noted, however that the majority of the discussion regarding the low-balling of ECS is explained to be a function of how ECS is defined, which short term feedbacks are included or excluded. 

For example,, none of the models include carbon cycle response feedbacks from melting permafrost which effectively reduces the amount of anthropogenic emissions of carbon to achieve 2XCO2 nor do they include land-based feedbacks that are already being observed to be in decline (sinks).


Seems to me from what you posted, from what was discussed back near the start of this thread, and from quickly skimming the last two pages,  that the one piece of significant evidence for a higher sensitivity is the possibility of a much higher cloud feedback.  This is not a slow feedback or a carbon cycle issue.  Currently the modeled warming rate since 1975 is 2.2C per century, and observed 1.9C.  If a higher cloud feedback is included then surely the modelled rate from 1975 to now would go up to be even further above the observed rate.

Finally, it should also be noted that the current body of climate models still being used today are still underepresenting both the rate of albedo shift in the Arctic and do not accurately model the albedo response even when sea ice is lost - as shown by observations from NASA of the Beaufort Sea.

By how much?  And again if a stronger Arctic ice feedback is put into the models then the models would presumably further overestimate the currently observed warming. 

Best image on Arctic Sea ice decline I can find is



Big gap between obs and model in 2012, but we are in 2018, and looks like we should be somewhere 4.5 to 5m.  Last year was 4.47m by ADS, 16 and 17 closer to 4m, and to date we are 500k more ice than last year.  so I'd say that the slowdown since 2012 we are still a little less than model but the gap is getting quite narrow - about the same size as the gap between observations and modelling for global temps.

129
Arctic sea ice / Re: The 2018 melting season
« on: July 19, 2018, 07:26:44 AM »
Comparing visuals on 2018 vs 2016 vs 2012.  And wow there was some crappy ice around in 2016/2012 by this date.  Definitely a good amount of crappy ice around Beaufort/Chukchi sector this year, and given the forecast of a strong warm front quickly surging through this area, and sustained strong winds with a strong cyclone, it will be something to watch.

130
Consequences / Re: Conservative Scientists & its Consequences
« on: July 19, 2018, 06:57:16 AM »
This thread started four years ago.  I recall lots of claims that new evidence implied a much greater climate sensitivity than the IPCC range.

Four years down the track, and the latest papers on climate sensitivity still seem to agree with IPCC.

First few from the google search that comment on possible values for climate sensitivity.
Emergent constraint on equilibrium climate sensitivity from global temperature variability  best estimate 2.8, likely range 2.2 to 3.4.  IPCC range is 1.5 to 4.5.
Global warming projections to 2100 using simple CO2 greenhouse gas modeling and comments on CO2 climate sensitivity factor Co2 sensitivity factor is 2.52, compared to IPCC 4.33.  Red flags on this paper include reference to Loehle and Scafetta, and statement of a value to 2 decimal places without a range.
Climate sensitivity estimates – sensitivity to radiative forcing time series and observational data Effective climate sensitivity is 1.9C, range 1.2 to 3.1.  Note effective not equilibrium.  Abstract claims consistency with IPCC and with models
Energy budget constraints on climate sensitivity in light of inconstant climate feedbacks  Equilibrium climate sensitivity 2.9.  Range 1.9-7.1

I note they are all largely observational based estimates.  I scan through to the second page to find something more model based.

The role of Hadley cell extent in determining the radiative effect of midlatitude clouds, and the resulting effects on CMIP5 models' climate sensitivity

No specific value for sensitivity in abstract, but they find that models with a realistic hadley cell expansion have a significantly lower climate sensitivity than models that over-estimate hadley cell expansion.  I haven't kept up with this thread for quite some time, did this paper get as much exposure on this thread as the papers finding higher climate sensitivity for models that have a more realistic representation of clouds?


Also since 2014, modern global temp trends (GISS, from 1975 as per Tamino breakpoint analysis) have increased from 1.66 C/century to 1.82 C/century.  This is still not as high as the highest temperature trend pre-pause at 1.88 C/century (1975 to mid 2017), or the CMIP5 trend of 2.25 C/century.

I also note that yet again the usual suspects have been convinced that this would be the year that Arctic ice would crash, and yet again the minimum looks like failing to seriously challenge 2012's record.  Assuming no amazing finish to the melt season this will be the equal longest period failing to set a new melt record in the ADS data set, equaling the previous record of 6 years between 1984 and 1990.

This thread started in 2014, and the period from 2014 is still kind of short to expect much change.  But serious projections of global warming started in the late 70s.  Today's estimates of climate sensitivity have not been significantly changed by the last 30-40 years of data.  Projections of temperature change have not changed substantially.  We have been close to, and maybe a little lower than these projections.


131
Arctic sea ice / Re: The 2018 melting season
« on: July 19, 2018, 12:39:40 AM »
Can anyone explain me how it is possibble that the past 3 winters were the warmest "ever" in the Arctic and yet summers are not much to talk about. Where does the extra heat from winter go? Why does it not show up in big extent losses later on?

It could be a simple case of luck resulting in three unusually warm winters at the same time as we have had two and on the way to a third not so warm summers.  Are the recent summers genuinely poor?  Or maybe the summers from 2007-2012 were unusually strong and we are back to a more normal pattern in summer?  I say poor and strong rather than cold/warm as I think there is more to it than cold/warm, although a large part is sunny/cloudy which results in warm/cool.  Also wind/ice export.  Perhaps the forgotten issue of this year is a low ice export via fram strait providing a strong boost to ice retention.  Or almost forgotten, I think it has been commented on at least a couple of times.

It will be interesting to see if the pattern continues, and increases the pressure to find an explanation other than blind luck.

A thread I posted recently may be part of the answer.

132
Arctic sea ice / Re: The 2018 melting season
« on: July 17, 2018, 01:54:54 AM »

Ocean currents are storing enormous quantities of heat in the deep
Are they (above the long term warming trend)?  Evidence? 


that are going to be released with the next El Niño and other oscillating long time currents. There's a 50% chance of El Niño forming this year: Be prepared for different graphs in a couple of months.

The deep water is much colder than most of the ocean, so if the water from the deep is 'released' the surface would cool not warm.  Warming in el nino events is not directly due to release of deep water heat, but due to changes in surface evaporation (due to changes in wind) and currents.  The changes in current are triggered by release of subsurface warm water from the western warm pool.

In the Arctic the deep ocean is warmer than the surface.  But it is already plenty warm enough to melt the surface ice multiple times over.

133
Arctic sea ice / Re: The 2018 melting season
« on: July 16, 2018, 11:34:52 PM »
This summer's weather may be good for sea ice this September, but this weather pattern is moving more ocean heat than normal northwards in the Atlantic and Pacific oceans.

Shades of 2006 perhaps.  A slow melting year, but I remember someone claiming that a pulse of warm water from the Atlantic during 2006 was a significant factor in the 2007 result.

134
Arctic sea ice / Re: The 2018 melting season
« on: July 14, 2018, 11:44:02 AM »
July is half over, and has been a big bust so far.  Forecast is for low pressure ice retaining weather for the next 7 days.  So unless the forecast/weather changes spectacularly July is going to finish a bust.  And if July is a bust the whole melting season is a bust in my opinion.

135
This premise is flawed. The Arctic was / is warmer than the continents in June (and July) and the

That massive heat dome over Europe looks a lot stronger than the heat over the Arctic.  Also note Greenland, and to some extent the Canadian Archipelago is part of the cold Arctic, that is ice covered regions that are not warming up as fast due to the persistent presence of ice.  I'd say the chart supports my theory.


136
The current Arctic cyclone has been quite intense.  968 vs 963 for the GAC.  Looking at Canadian Analysis charts it covers only a fraction of the Arctic basin, compared to GAC covering the majority.  However the squeeze against the high pressure towards the Siberia Sea looks to have produced tighter wind gradients and presumably stronger maximum winds than the GAC, but over a relatively small area.

What struck me with this cyclone is the intensity of the associated warm air mass over Siberia.  After the central Arctic has generally been a little on the cooler side (compared to recent years, but still warm compared to longer term stats).  Temperature contrast plays a big role in cyclogenesis.  And while much has been said about Arctic amplification, and warm arctic cold continents, I think the situation may be reversed in summer.  During summer, particularly early summer the Arctic is still dominated by ice. This pins the surface air temperature close to 0 and the basin is pretty similar to what it was several decades ago.  The surrounding regions are getting warmer, thus we have warm continents, cold Arctic, and increasing frequency/intensity of Arctic cyclones.

And some seasons we see a transition from strong high pressure dominated weather early in the melting season to low pressure dominated weather.  2010 and 2011 really stood out as seasons that early on had severe melting weather, with some dramatic (at the time) early season stats, but then fell flat quite significantly as cyclone dominated weather took hold.  2013 was the year of the persistent arctic cyclone where the cyclones started early and just kept going.  While the surface temperature may be pinned close to 0, the atmosphere above has been getting warmer (eg 925hp temps).  But when we get a significant cyclone, mixing of the air column with the surface pinned at 0, plus clouds etc result in the relatively cool surface extending through a more significant portion of the atmosphere, thus increasing the warm continent cold arctic temperature contrast and making further cyclones more likely.

So negative feedback.  But perhaps only sometimes.  In 2012 we saw both early season cyclones that failed to establish a more persistent cyclone shield, but spread the ice and allowed intermittent high pressure weather to pump lots of heat into the mix of ice and open ocean, and then the very severe GAC.  The GAC was of course followed by massive loss of ice, although there is an argument that the ice had already been set up to melt by previous conditions and the GAC played a relatively minor role.

137
Arctic sea ice / Re: Don't read this thread
« on: July 10, 2018, 03:24:27 AM »
Took me a while but I eventually read this thread, and was amused. 

Maybe if the thread was titled '10 reasons why you must read this thread - no 7 will blow your mind' I would have refused to read it.

138
Arctic sea ice / Re: Will we see it before it happens?
« on: July 10, 2018, 03:13:46 AM »
I think most of us will have some idea of a blue ocean event at least a week or two before it occurs - if the ice is at 1.5m half way through August even the most conservative of us on this forum will have to start suspecting something is up.  Unless we see flash melting like no flash melting in the past.

The question is how early will be able to tell?  And an interesting corollary is how early can we tell for certain that this is not the year of the first blue ocean event?  Depends on how it happens.  Some (most?) of us suspect that freak weather conditions could result in a blue ocean event any year.  I know I do even though I believe that regular blue ocean won't happen until the second half of this century.  Such a freak would be very difficult to predict - we might think we have a perfect storm melting situation in June, but how do we know it won't turn cloudy and cool in July.  Alternatively we may see continued gradual lowering of the record until the existing record is about as close to a blue ocean event as typical annual variation.  Then any strong start to the melt season should lead to much speculation about whether that will be the year.

139
Arctic sea ice / Re: The 2018 melting season
« 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.

140
Arctic sea ice / Re: The 2018 melting season
« on: July 10, 2018, 12:45:49 AM »


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


141
Arctic sea ice / Re: The 2018 melting season
« 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.

142
Arctic sea ice / Re: The 2018 melting season
« 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.

143
Arctic sea ice / Re: The 2018 melting season
« on: July 08, 2018, 05:34:14 AM »

Why don't you post maps and analysis instead of observations that are completely lacking in support? The amount of heat import this year has been the worst ever. I would post maps but oren will yell at me so go to ESRL and look for yourself. Satellite data also shows the most open water in the High Arctic on record.

As Neven posted a little while back the temperature in the Arctic was the 6th warmest ever.  Maybe you should post some data or analysis to back up your claims.

144
Arctic sea ice / Re: The 2018 melting season
« on: July 04, 2018, 05:08:15 AM »
Whatever the final outcome will be, I'm fairly sure that we'll see an early September minimum this year.
Why? Early summer minima are due to cloudy weather (while the sun still shines). If there are open skies, there won't be an early freeze onset. So what is convincing you of the contrary?

Not sure what Lord Vader's reasoning may be, but I think we might be biased towards an early minimum because the core ice has been somewhat cooler and the fringe ice much warmer.  So late in the season the easy to melt ice will be gone and whats left will be stronger.  Still my personal opinion is that the weather near minimum would be more important.

145
Arctic sea ice / Re: The 2018 melting season
« on: July 03, 2018, 11:01:54 PM »
NCEP Reanalysis temperature data for June (since 1948):

Arctic: 6th
Atlantic: 46th or thereabouts
Siberian: 1st (more than 1° C higher than previour record)
Pacific: 12th
Canadian: 37th or thereabouts

Interesting and a little surprising to me that it was also the warmest June since 2012.  Combined with the very warm winter there may be potential yet to challenge for a record. 

146
Arctic sea ice / Re: The 2018 melting season
« on: July 01, 2018, 09:57:56 AM »
Here is 6/19-28 2018 minus 2012. I would call this severe abrupt and apocalyptic climate change. We have clearly hit an inflection point re: continental albedo and sea ice. Maybe the Mayans were right after all and this occurred in 2012?  :o

Also ^ data directly refutes the notion that the weather has been beneficial to the ice. It has been the worst June on record.



Two points.  Firstly there are no direct observations of surface temperature in the arctic,  the output is not observational data, but a weather model output.

Secondly 19th to 28th of June is not all of June.  My reading of MODIS images is that the early part of June 2012 was much sunnier with lots more surface melting than we've seen this year, and then around the 21s a low pressure system moved in causing cloudy conditions in 2012 for much of your analysis period - and by the time the cloud cleared at the end of June a significantly dispersed pack was revealed and sunnier conditions early in July did a lot of damage on this weakened pack. 

147
Arctic sea ice / Re: The 2018 melting season
« on: June 29, 2018, 03:04:35 AM »
I know that it is overwhelmingly likely that you are correct, Michael, but I have a novice's question to ask.  If the Arctic ice is fresh, then its melting point is 0 C, I presume.  If the ocean water below is saltwater, then it can be up to -1.8 C, which means that it is then colder than the melting point of freshwater ice.  So in this simplistic formulation, the ice should not melt -- it should even form during these conditions at the bottom of the ice, even without a lot of heat being sucked way at the interface between the ice and the atmosphere.  Now, I suspect that salinity/entropy has got something to say here, but what exact physical principle is at work?  Is it ultimately entropy -- that the salt ions and water molecules will tend to become as mixed as possible?  And/or is it that the ice has a lot harder time growing when salt ions are present?  Or... (I often discover something I never thought of...)   


I hadn't thought about that angle.  The salty water below would not freeze and neither would the ice melt.  It is the multi-year ice that is fresh and the first year ice is much saltier, and there is a good amount of first year ice north of 80N. 

Looking through some MODIS images, channel 3-6-7 shows quite a lot of red in the high Arctic at the end of June in 2007,2008, 2010, 2011, 2012, so some substantial surface melt.

Current conditions - its almost a tale of two Arctics.  The Pacific side has some significant ice dispersal deep in the Beaufort, and plenty of red suggesting surface melt.  From Greenland towards Laptev there is quite an area of solid looking ice that is still supporting a crack/lead pattern instead of separating out into individual floes, and little reddening/surface melt.  I'd say the Pacific side is well on the way to a major meltout, and the Atlantic side will hold up quite well, suggesting that an extreme outcome in either direction is less likely than normal this year.

148
Arctic sea ice / Re: The 2018 melting season
« on: June 29, 2018, 12:39:22 AM »
I'm a bit late to the friv bashing session.  But I'll add that if the ice isn't freezing, it is melting.  The ocean below is always warm enough to melt the ice, and freezing only happens when the air above is far enough below 0 to more than balance out the slow addition of energy from below.  I would say that there is never any freezing happening in June, and that the ice north of 80N is basically always melting in June, but that the melting except possibly in rare circumstances (and near the Atlantic edge around Svalbaard) is too small to matter.

149
Arctic sea ice / Re: The 2018 melting season
« on: June 25, 2018, 04:44:00 AM »
No comparison 2018 vs 2012 at this stage IMO.  2012 had solid basin wide surface melt from early June, whereas this year has only had solid surface melt through the Russian side.  2012 had a significant ice dispersion event which created mixed floes/open water in a swath from Kara right through to Beaufort.  This year we had a strong low, but it was only strong through the Kara/Barents sea which are typically dispersed this time of year, and weakened dramatically as it entered the main Arctic basin, and has served only to protect the ice with cool cloudy conditions.  There is an area of dispersed ice in Beaufort but nothing compared to 2012.

Comparison to 2013 - both had very low starting thickness.  2013 as a follow on from 2012.  This year after an unusually warm winter.  Both years have started with substantial cool and cloudy conditions due to low pressure, but in 2013 the low pressure was strong and central enough to rip apart substantial areas of dispersed ice near the pole towards Laptev through to Barents region.

So arguably a poorer start to the melt season than even 2013.

edit: current forecast should push things ahead of 2013 quite rapidly IMO.

150
Consequences / Re: Global Surface Air Temperatures
« on: June 21, 2018, 02:52:56 AM »
Thanks wili.



Why does the acceleration on that chart look unreasonable to me?

This chart looks more reasonable:



But it reaches close to 8 degrees, in contrast to the 5 of the first chart (land only vs land/ocean?).  I think somehow the combination of higher scale, and more jagged detail somehow makes the first chart look scarier than the second charts lower scale, focus on 2000-2100 only, and smoothed trend, even though the second one reaches a higher number.  Funny how the mind works....

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