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Messages - Jim Williams

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1
Arctic sea ice / Re: The 2017 melting season
« on: May 24, 2017, 07:30:47 PM »
The expectation of meltponding in high pressure conditions is repeated whenever such conditions are forecast. I have not seen a rationale behind that expectation, or much evidence that these predictions are reliable. No doubt there will be many more predictions like this in the coming weeks and at some point there will be meltponds, but I very often see the correlation which can once more be observed at Obuoy14: low pressure, clouds and raised temperatures. I attribute this to inflow of warm moist air, and believe more rigorous observations by scientists confirm this.
This has been posted so often I can't be bothered to dig out supporting information again, which will be ignored as usual by people who seem to prefer what their gut tells them.

My prediction for Obuoy14 is rising air pressure will bring clearer sky and lower temperature.
(which will not protect the arctic ocean from a most likely bad i.e. low ice melt season, by the way, before the usual opinionators start shouting at me)

I tend to agree.  I think an Ocean climate is more important than a mere bit of sun on the desert of ice.

Only time will tell.

2
I voted "No gap will increase mainly for reasons other than albedo", but albedo is important. Specially over land. I think the gap will increase because the remaining ice will be easy to melt, warm air will keep flowing in and I think there is huge potential for export through the garlic press.

About the only thing I might add to that is that the broken ice is subject to wave action.  (And at some point will become subject to upper ocean mixing -- though I don't know when.)

3
Arctic sea ice / Re: Stupid Questions :o
« on: May 19, 2017, 08:11:09 PM »
coulee?


Having grown up in Washington State on the other side of the mountains from Grand Coulee Dam, this seems right to me.  The Coulees run along the Columbia from just about at the dam to about Mount Hood.

http://www.sevenwondersofwashingtonstate.com/the-channeled-scablands.html

4
Arctic sea ice / Re: Stupid Questions :o
« on: May 16, 2017, 05:18:11 PM »
since the oceans are warming in general, that cold spot, i relation to the surrounding seas, will ultimately still be warmer or the same like before. hope it's clear what i'm heading at.

a 2C colder spot in 10C water is 8C while while once it was 6 or 8 C for example. further i do not believe in those scencarios at all. even if the gulf stream will start dropping to the sea-floor 1000km earlier, it will still do it's job for most of western europe, perhaps, due to the generally warmer waters flowing up from the carribian even more so.

however, this is all prone to a huge amount of speculation due to its complexity, it's weven possible that the very very cold (1-2C waters flowing down from greenland will once simply free fall to the see floor, at least if the difference in temperature is great enough to compensate for the difference in salinity, or, it will first start to reduce salinity and drop to the sea-floor once salinity reaches a level where the difference in temperature has the great impact. last but not least we could face a different behaviour in winter and in summer, simply too many unknowns to make a bold statement like "IT WILL" IMO
We can speculate, or we can note that the Western Boundary Current (Gulf Stream) has trended poleward and sped up over the last couple of decades.

Whatever theory the idea of the currents slowing down and stopping is based upon, exactly the opposite has happened so far.

5
Arctic sea ice / Re: The 2017 melting season
« on: May 15, 2017, 11:41:27 PM »
I noticed that too. I wonder if there is a real physical phenomena behind this or is it an artifact of the measure.
Because it coicides with spring time and a weather pattern that tends to force cold wind across the Arctic Basin toward the Fram and Svalbard? It is not a exact science, but there might be a correlation. If the weather pattern is more frequent lately than in the past century...
Last year it did not cross but it was close.
Later in July August expect again negative anomaly esp this year with so much FYI... I bet! At least while we dont end up with a blue Arctic

In Spring the weather changes.  This happens every year with the same unstable systemic behavior we are seeing globally as the temperatures rise.  When it starts to warm up the weather becomes unstable and unpredictable -- both every year and every climatic warm spell.

Basically, we are seeking a new attractor...whether by the year or by the eon.

6
Arctic sea ice / Re: The 2017 melting season
« on: May 13, 2017, 12:45:19 AM »
I've only seen a spring river breakup once, but I remember it as both fast and dramatic.  Is it ok for me to consider the Nares Strait a river?

7
Arctic sea ice / Re: 2017 sea ice area and extent data
« on: May 13, 2017, 12:14:18 AM »

So is it that the outlying areas (which will melt out) are holding on, maybe due to the "wacky" weather whereas the key, core area is already declining ?

Isn't that what I am seeing in the Nares?

Weather isn't that wacky...the cold that used to stay at the pole has to dissipate somewhere.

8
Arctic sea ice / Re: The 2017 melting season
« on: May 12, 2017, 09:57:05 PM »
The Atmosphere is the weather.  The Ocean is the climate.  It's too early to tell, but I think this is the year we actually see climate change as weather.  The collapse of Nares was kinda a BIG HINT.

WACC is in our future, but I think Cold Continent is only in comparison, and not some sort of real cold.


9
I voted "No gap will increase mainly for reasons other than albedo," but I did that because I took the question as "albedo this season."  I think that albedo is the major ultimate cause after CO2 in making the Arctic warm faster that everywhere else, but I don't think it a main proximate cause.  Thus, I don't think open water early in the year is all that important in determining the volume late in the season.

10
Arctic sea ice / Re: The 2017 melting season
« on: May 11, 2017, 06:41:26 PM »
What is happening in the Arctic now?
Let's see if I can do a gif....

11
Please try to stay on topic. -- j.p.

<snip>

12
Consequences / Re: California weather extremes and climate
« on: May 06, 2017, 01:46:39 PM »
I am not advocating geoengineering though I sadly believe that it will be attempted in the next 15 years.

I have to agree.

13
Consequences / Re: California weather extremes and climate
« on: May 05, 2017, 11:44:40 PM »
we already know that aerosols cool the earth that is the basic science of it and the basic science alone is sufficient to promote an argument for geoengineering. 

I am not sure what you believe my aerosol argument is....
You just stated it in the preceding paragraph, and as I believe we screwed up 200 years ago I am not inclined to agree with screwing it up once again.

I just don't believe we know what we are doing.  Therefore I am not inclined to agree with any sort of geoengineering "quick fix."


14
Consequences / Re: California weather extremes and climate
« on: May 05, 2017, 06:38:37 PM »
My favorite chart, End-April volume, not even remarkable. A simple continuation of what looks like a linear trend, past a "plateau" that may have been random variability in hindsight.

This is good, however, it must also be suggested that the 2013 & 2014 'recovery' years were black swan events and are pushing the trend anomalously higher (straighter).  If these years effects did not occur and the volume gain during those years was removed then the trend would fall well below the long-term linear trend.

I believe for several reasons that these years events were a statistical outlier over 4 sig.

"Black Swan" seems a bit too extreme.  The paleontological evidence seems to indicate a bit of stuttering before the actual climate switch.  This is also consistent with how natural systems generally tend to undergo a change of state in General Systems Theory.  Most of the time the system tends to choke a few times before flipping to a new state.  If you think about it, that is what happens with things like computer networks which are in the process of crashing -- they stutter and then fail.

Jim

what you are saying is true to an extent, however we are not operating within a black box environment.  The 1976 and 2014 Gulf of Alaska blocking pattern has a distinct profile that is largely a result of varying upper troposphere aerosol loading.   I have been looking at this for a number of years now and the key indicator is that the Global Circulation Models (GCMs) used to model geoengineering (global dimming) show a strong and persistent blocking ridge in this region.

Therefore, while state-change activities are definitely happening, the drivers of specific systemic changes always have physical drivers.  It appears that the 2013/2014 cooler summers (and warmer winters in Alaska, drought in California and record snow levels on the east coast) are driven by regional shifts in high-temp process emissions of  aerosols (as happened in 1975 when Europe rapidly reduced their emissions but U.S. and Asia emissions were continued).

The 2013 event was similarly produced by reductions in U.S. emissions post 2007 crash but shifting this manufacturing to China who engaged in a command economy overproduction surge in 2013.

Without this knowledge this could appear to be a strengthening of natural variability under a shifting climate regime, but this is a black box analysis of a black swan event. 

This video has excellent analysis from people who were not aware of this aerosol driver.

https://www.youtube.com/watch?v=on0QmcDFgrg

I've been working on trying to absorb your aerosols argument, and I am tending to bifurcate on the matter myself.  I climbed Mount St. Helens twice before it blew up.  I am not unaware of what Pinatubo did.  At the same time, your analysis can be misused to promote a geoengineering solution, and I see no evidence that we understand the system well enough to predict the results.

15
Arctic sea ice / Re: Latest PIOMAS update (May)
« on: May 05, 2017, 01:02:25 AM »
My favorite chart, End-April volume, not even remarkable. A simple continuation of what looks like a linear trend, past a "plateau" that may have been random variability in hindsight.

This is good, however, it must also be suggested that the 2013 & 2014 'recovery' years were black swan events and are pushing the trend anomalously higher (straighter).  If these years effects did not occur and the volume gain during those years was removed then the trend would fall well below the long-term linear trend.

I believe for several reasons that these years events were a statistical outlier over 4 sig.

"Black Swan" seems a bit too extreme.  The paleontological evidence seems to indicate a bit of stuttering before the actual climate switch.  This is also consistent with how natural systems generally tend to undergo a change of state in General Systems Theory.  Most of the time the system tends to choke a few times before flipping to a new state.  If you think about it, that is what happens with things like computer networks which are in the process of crashing -- they stutter and then fail.

16
Arctic sea ice / Re: Latest PIOMAS update (May)
« on: May 04, 2017, 10:54:06 PM »
Total freeze:

This is probably the most important statistic Neven.  Can you give us a comparison with the 20th Century?

17
Arctic sea ice / Re: Latest PIOMAS update (May)
« on: May 03, 2017, 10:00:36 PM »
Uh-oh:





I'll post the rest later, but wanted to get these two up now...


I can see why...your projection from here for various years sort of says it all.

18
Arctic sea ice / Re: Latest PIOMAS update (May)
« on: May 03, 2017, 05:01:00 PM »
Another tiny piece of detail, the growth from End-March to Apr 25th was ~0.32 km3, more or less the average of the last few years. The negative feedback of low volume leading to higher growth failed to materialize.

Yes, according to the model.  The physical reality 'feels' like it should yield a higher growth.  Any ideas on what would drive PIOMAS lower than expected?

The Atlantic Ocean.

19
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: April 30, 2017, 07:28:23 PM »
It should be expected that sea ice extent will continue to lag behind volume until some critical threshold of volume is reached and then SIE will collapse quite suddenly (I expect this to occur sometime around 750 km^3).

Can you explain your rationale behind the 750 km^3 figure?   I fully expect the regime to change when there is no longer enough ice to keep the ocean cold, but I have not so far found a good metric for when this will happen.

20
Arctic sea ice / Re: The Fast Transition
« on: April 29, 2017, 12:27:34 AM »
The snow discussion is getting off-topic.
I have to disagree in that an increase in snowfall seems to be one of the main characteristics of previous sudden warmings.  I might also add that there has been a marked increase in snowfall with the last winter.

Of course, winter snowfall is a marker, not the event.

21
Arctic sea ice / Re: The Fast Transition
« on: April 28, 2017, 09:13:49 PM »
I still believe we will soon hit a tipping point where the ocean is warm/ice-free enough to really rev up fall/winter snowfall numbers, enough so that we see snowpack begin enduring more and more readily into spring and early summer. We are already seeing this manifest in the anomalously high snow-volume numbers seen this year. How much more snowcover needs to build in fall/winter for extent to follow suit in the spring? I do not think we need that much more for this to begin occurring, though I could obviously be wrong (and the general consensus among most posters here is that I am wrong, so there's that too).

Nevertheless, the relationship between NHEM snow volume and arctic sea ice volume seems to have an inverse correlation, and as we continue seeing new lows throughout the year, it will be very interesting to see whether this relationship strengthens or weakens -- my bet is on the former.
If we had not been so overloading the atmosphere with C02 I think you'd be right, but as it is I think the snowpack will be a fleeting phenomenon.  I might buy into a short transition where the snow lasts as long as it did before....but not a state where the snowpack has any meaningful impact on overall climate.


22
Arctic sea ice / Re: The Fast Transition
« on: April 28, 2017, 08:25:44 PM »
bbr2314 - your second graph would seem to support a "more snow area in the winter but melts faster in the spring" hypothesis. Will be interesting to see what happens to snow extent in the next few weeks.

If there is greater snow cover on Northern Hemisphere land in Fall/Winter that should tend to reduce temperatures (although insulating the ground beneath). With increased cloudiness over the open Arctic Ocean in the darkness of Fall/Winter, it will tend to stay warmer. The overall effect may be to reduce the temperature differential between the Arctic and the rest of the Northern Hemisphere further?

That would be Warm Ocean Cold Continents (WOCC).  The best evidence we have on the past tends to support this as a regime.  One where the Arctic becomes a mist shrouded maritime climate and (at least at first) the continents become seasonally heavily snow covered holders of the remaining cold.

That may, or may not, give way to an equable climate.


23
Arctic sea ice / Re: The Fast Transition
« on: April 28, 2017, 02:20:38 PM »
I can only respond that the ice cores tell us there are sudden and complete changes in the climatic regime.  These seem to be in years or less, not centuries.


I suspect you're referring to events like the Younger Dryas and the various Bond events? The consensus is that these are all caused by freshwater pulses in the north atlantic (indeed they're not global phenomena) caused by large lake releases. In theory this could be replicated by rapid total ice melt, but Lake Agassiz was around 22,000 km3 in volume which is ~4 times the current summer minimum ice volume so it's hard to see it having the same sort of effect. Indeed, the seasonal arctic ice volume variation is around 20,000 km3 and, coincidentally, the annual loss from the Greenland ice cap is about the same again, which suggests that the ocean is absorbing 40k km3 of fresh water annually anyway (plus whatever drains from siberia). So you would likely have to have a marked increase in Greenland melting to trigger climate changing amounts of freshwater release.

I've never worked it completely through before but those figures do kind of suggest that even should all the summer ice melt out there wouldn't be a dramatic effect on the global climate (at least not from from freshwater pulses) and we should be more worried about the surface mass balance of the Greenland cap.


I think you are referring to the beginning of the Younger Dryas, not the end of the Younger Dryas.

http://www.pnas.org/content/97/4/1331.full

The Greenland records show that climate changes have been very large, rapid, and widespread. Coolings were achieved in a series of steep ramps or steps and warmings in single steps. The more dramatic of the warmings have involved ≈8°C warming (8, 25) and ≈2× increases in snow accumulation (9), several-fold or larger drops in wind-blown materials (17), and ≈50% increase in methane, indicating large changes in global wetland area (5, 24).

For the best-characterized warming, the end of the Younger Dryas cold interval ≈11,500 years ago, the transition in many ice-core variables was achieved in three steps, each spanning ≈5 years and in total covering ≈40 years (26). However, most of the change occurred in the middle of these steps. The warming as recorded in gas isotopes occurred in decades or less ( 8 ). The most direct interpretation of the accumulation-rate record is that snowfall doubled over 3 years and nearly doubled in 1 year (9). Several records show enhanced variability near this and other transitions, including “flickering” behavior in which climate variables bounced between their “cold” level and their “warm” level before settling in one of them (27).


24
Arctic sea ice / Re: The Fast Transition
« on: April 27, 2017, 11:26:14 PM »
Will a "Blue Ocean" event in September trigger positive feedbacks that will rapidly (e.g. a decade or so) lead to a seasonally ice free Arctic with blue ocean being the predominant state throughout the summer months?
These feedbacks would include:
- Albedo Effects (possibly mitigated by cloud effects)
- Reduced separation between the Arctic and Northern Hemisphere climate regions, allowing for greater amounts of heat transfer into the Arctic
- Greater level of storms and waves driven by open ocean (and heat contrast between ocean and land)
- Mixing of the water column in the absence of a thick ice cover, bringing up deeper, warmer water to the surface

With the extra heat taken into the open waters during Spring/Summer being vented into the atmosphere in the Fall/Winter months, will the freezing season be significantly reduced (i.e. less and less FDD's) - reducing the ability of the ice to reform and thicken?

Could the Arctic then transition to near ice free year round as the increased energy taken in through the spring/summer, together with greater heat transport from the south, reduces the FDD's further and further?
- Thinner ice at the start of the melt season leads to greater warming from reduced albedo, leads to less FDD's, leads to yet thinner ice the next melt season.

I can only respond that the ice cores tell us there are sudden and complete changes in the climatic regime.  These seem to be in years or less, not centuries.

I will go with the ice cores rather than the models.

25
I have just been catching up with this forum. Someone mentioned that anyone putting a vote for 2090+ is a denialist. I am anything but. In fact I see predominately  ice free conditions by September starting no later then 2030 and would not be surprised to see it before 2020. The point I made and I bbelieve there are others who voted for 2090+ see the same thing, is if the weather hit perfectly, you could end up with ice extent over 1M km2 in any single year. To deny that possibility means you are looking at Arctic temps by mid summer getting no lower then 5C in any particular year, which even the most extreme forecasts do not call for.

That is very logical, however, even the most extreme forecasts do not agree with the paleontological evidence.  The evidence is for sudden and generally rather extreme change.

26
Arctic sea ice / Re: The 2017 melting season
« on: April 20, 2017, 11:46:59 PM »
So much data saying Melt (DMI, Arctic anomaly, Fram export, destruction of  sea ice sheets integrity from multiple observations  etc. etc.). And yet jaxa sea ice decline remains at a glacial pace, and sea ice volume not declining yet.
And still at least 2 weeks before getting April PIOMAS  update. Am I the only one in confusion ?
I think the answer is dispersion, GC.  Less ice, spread more thinly.

AKA -- Winter Storms.

27
It's interesting that the poll is basically about when the Arctic's transition to a new climate state will be essentially complete (and I am positing that the transition will be abrupt and come within the next 5 years), but the discussion also raises the question of when this transition really began - and again I am positing that it began probably many years before we crossed the 350ppm CO2 threshold.

Off topic but these days the Keeling Curve shows CO2 concentration > 410ppm.  :'(

The transition began 8,000 years ago, but exponential functions have a habit of starting out very flat and then getting extremely steep.

I'll agree about the 5 years (or less).


28

The transition from a desert to a maritime climate happened in late December 2015.

Based on what? On some plumes of humidity over the Arctic? You don't know if that is an annual variation, or decadal, or what. You know as much as I do or any around (except maybe the owner of the site, Rob, Dr. Ding and a handful more), which is nothing.

Based on a graph???? Lol. Based on clairvoyance, a vision in dreams or what?

In September 2012 "a tipping point was crossed", in November Sandy . But Did we? Or didn't we? Cause 2013 and 2014 were pretty unispiring seasons for some that shut their mouth for a good and nice while.
Same we heard when Katrina in 2005 "We will never come back to past seasons". Well, in what respects to Atlantic hurricanes, we are back to old times.

2017? Does not look good, if you ask me even worse than 2016, but how I wish it was otherwise.
The DMI 80N prior to 2015 all look pretty much the same as all but the last few days of 2015.  The DMI 80N for 2016, and so far in 2017 have the interesting characteristic that the wintertime temperatures NEVER fall to the long term mean.

In this timeframe, the discussion here was about the remarkable number of storms entering the Arctic.

29
This graph shows the same story even better:
...
Indeed there are similar versions of this chart floating around, some with smoothed data, some not, etc.
The main point of this chart is that, when the trendlines meet is when total summer melt = total Arctic sea ice from previous winter(s).

Chris Reynolds used a version of this chart to predict zero ice by the mid 2020's, but he was assuming a small, linear drop in maximum (April) Arctic sea ice volume. Unfortunately he posited a "slow transition" (see the thread by the same name here on ASIF) to a sea ice free Arctic based on this small, linear drop in maximum (April) Arctic sea ice, itself based on a simple thermodynamic negative feedback (heat loss during Arctic winter getting higher and higher as the ice gets thinner and thinner, hence the ice thickening being faster and stronger after a summer with more melt).

2017 is showing that AGW and positive feedbacks resulted in a record, step drop in Arctic sea ice volume at the end of March / beginning of April (see the PIOMAS thread). In other words, positive feedbacks have largely overwhelmed the negative feedback described by Chris in the winter 2016/2017 and the two (quadratic) trendlines should meet sooner than the mid 2020's.

Another way of stating what is happening in 2017 is to say that we have just entered a new Arctic climate regime which will stabilize when we get a year-round, totally ice free Arctic ocean, and the transition from the current state should be quite fast. No "slow transition", but rather, an abrupt one.

Quoting from Tamino's blog: "The loss of Arctic sea ice is so great, so rapid, so alarming and surprising, it’s powerful evidence of dramatic man-made climate change."

(from https://tamino.wordpress.com/2016/09/28/its-the-ice-stupid/ )

The transition from a desert to a maritime climate happened in late December 2015.

30
Arctic sea ice / Re: The 2017 melting season
« on: April 19, 2017, 11:25:34 PM »
could it be that the increased water vapour content of the atmosphere will result in more snow being deposited on high altitude glaciers?

That is the most common WACC (Warm Arctic Cold Continents) theory.  Basically, the theory is that until "General" warming overcomes local conditions the continents will get colder and wetter as the Arctic fails to keep the cold locked up in the far North.


31
We are driving the climate, except we are driving blind.

To put it another way.  We are the Unknown Unknowns.

32
...locomotive that has already derailed a minute ago will stop moving at point x or two meters further away.
More like 57 meters...

But what is a few inches between friends?
Does it matter?
Sticking to the train wreck metaphor, does it change the cost of the disaster? Or the number of victims? Shouldn't we (and I mean, we as in humanity/civilization) rush to help the victims instead of wasting time with overanalyzing the path of the locomotive in the remaining two seconds of the reel, and how much water and coal were still left before it crashed, etc, etc, etc?

Perhaps we are just happy with watching Arctic sea ice melt away because it's very much an abstract thing, and so huge a disaster that our minds cannot quite apprehend it.

But the fact is, some of us in this excellent forum (myself included) publicly complained to Dr. Ding about his "detachment" from the Arctic sea ice melt disaster. Aren't we (and this time I mean the vast majority of users of this excellent forum) in a similar way just as irresponsible?
Actually you are proposing that I have a specific valuation upon a certain kind of life.  I do not.  I am here watching what is a very interesting change in the global climate -- I am not here assigning a valuation upon that change.

In fact, I find the watchers who are also excited and then end with some sort of disclaimer rather annoying.

33
Arctic sea ice / Re: Stupid Questions :o
« on: April 18, 2017, 11:04:48 PM »
Jim, You should read through the whole tread but here is one post from ASLR. Much of the thread has to do with Antacrtic bottom water formation and further info on the North Atlantic Bottom

ASLR is talking about models and theory, not data.  While I think his take on theory and models is interesting, that is not what I am interested in...I want to know what data we have on the subject of the return of heat from the deep water to the surface -- if any.


34
...locomotive that has already derailed a minute ago will stop moving at point x or two meters further away.
More like 57 meters...

But what is a few inches between friends?

35
Arctic sea ice / Re: Stupid Questions :o
« on: April 18, 2017, 04:59:33 PM »
I tried to formulate a question for Google seeking information on what we know about changes in bottom water temperature and salinity over the last few centuries and came up with nothing.

Anyone know the right question to ask?  I am specifically interested in what we currently know about when bottom water returns to the surface after becoming bottom water -- and how much heat it contains.

36
Arctic sea ice / Re: The 2017 melting season
« on: April 18, 2017, 04:16:38 PM »
The MASIE Time Series Plots do seem to be indicating the Pacific side is opening up.

37
I'm convinced the first year with Sept SIE less than 1m will also be the last. However, when will that be is much harder to answer. Before I emit my vote I want some time to see how this thin first year ice reacts to the melting season. It could very well be that the first and last <1m SIE happen this year.

However if it doesn't happen this year, maybe the Pacific and the Atlantic end their warm cycle, lowering atmospheric temperature and humidity. Maybe then that Arctic makes a recovery. If so, then the Arctic might be safe for maybe a decade or two.


I'll vote after I see more. So far it is not looking good.

I'll agree with this analysis.  Depending upon the time of year of melt-out the first year which has a point in time with no significant ice will also be the last year with significant ice for a very long time.  I'm inclined to include Winter as well as Summer in that, though with a bit less conviction.

I don't know when it will happen, but when it does happen it isn't going to care whether it is Summer or Winter and it isn't going to care about the following Winter a whole lot.

The permafrost will slow down the continents a bit, but it will not be all that long before they too will not have significant Winters.

38
Personally, I think anyone that voted anything other than 2020-2030 in the poll above is a denialist, consciously or not.

There wasn't a 2017-2020 slot, so I didn't vote.

39
Arctic sea ice / Re: What is a model?
« on: April 16, 2017, 05:23:33 PM »
It has to be said that increasing complexity and sophistication does not automatically produce a better result.
And indeed, the impetus behind this thread was the use of an exponential extrapolation to forecast Sept sea ice, while the use of the simpler linear function is more widely accepted for the job (and rightly so, imho).

There's no reason to prefer either.  The driving changes have been built in over centuries, and each force has its own peculiar timeline for manifesting.  Changes in bottom water temperature might take millennia to produce a resulting change in atmospheric circulation.  I am more inclined to believe the people who tell me our current climate changes are due to the invention of agriculture than to those who tell me last week's CO2 is to blame.  (Though I do personally think it was the Industrial Revolution.)


40
Arctic sea ice / Re: What is a model?
« on: April 16, 2017, 01:24:38 PM »
A model is a small imitation of the original.  Models always lack at least some of the fine details in the original -- otherwise they are called replicas.
The few models that I've met in person all appeared, to my jaded eye, to possess very fine details indeed. ::)


Terry

And they've all been pretty much identical...

41
Arctic sea ice / Re: What is a model?
« on: April 15, 2017, 09:13:34 PM »
A model is a small imitation of the original.  Models always lack at least some of the fine details in the original -- otherwise they are called replicas.


42
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: April 15, 2017, 01:10:25 AM »
<snip, wrong place: N.>

<snip, wrong place: N.>


43
This year....

I don't really know when it will happen, but I am convinced that when the flip happens it will be sudden and complete.  Depending upon what time of year essentially ice free happens it will be the same year as ice free all year.

I define essentially ice free as the DMI 80N jumping a few degrees above 0C for several days running.

44
But the way you criticize the research, implies that you know how it could've been done better. If not, you are saying that the research shouldn't have been done in the first place. But don't we want to know the respective contributions of AGW and natural variation to Arctic sea ice loss? That's a legitimate and interesting scientific question, right?

I can think of better ways to spend our soon to be very limited research dollars.  More satellites would be nice.

45
My only complaint about the "alarmists" viewpoint is the claim that we need to do anything.  First I think it is too late to do anything, and second I think that trying to do anything is likely to lead to an even worse result.

We screwed up the climate with the Industrial Revolution.  End of story.

46
Arctic sea ice / Re: Stupid Questions :o
« on: April 07, 2017, 05:54:26 PM »
Based on incoming insolation and Outgoing Longwave Radiation (OLR), I'd say the equilibrium point is between the last week of March and mid-April depending upon which arctic latitude we want to look at.
Interesting, and I think might be close to answering the real question.  If I assume the thermal conductivity of ice at 0C is the point at which irradiance would start to melt the surface of the ice, and if I am correct in interpreting the 2.20 in the table in the link below as the same as 220 in your graphs then it would give about the same result  as you have suggested for total OLR.

The difference being that I think real dates could be assigned (with enough thought) for when the Sun is hot enough to start melting the ice.

Am I at all close here?

I'm not sure what water/ice has to do with it.  If we did the same calculation at 30°N or at the equator we would come up with a different value for insolation, OLR, and the equilibrium date.  Water/ice will have nothing to do with the calculation.

The differences at the same latitude can be significant. Compare south-central Greenland to areas of the north Atlantic just a few degrees east.  Insolation is constant at the same latitude, but OLR varies by 35 W/m^2 or more.  This would lead to an equilibrium difference of a couple of weeks or more.

The Fact that OLR varies is exactly what is wrong with it as a measure of the arrival of Spring at a given latitude.  The "emotional" Spring happens when the Sun is hot enough to start melting the ice.  It seems to me that the original question is basically "on what date can we expect Spring at a given latitude?"

I posit that Spring has arrived when the Sun is hot enough it can melt ice -- not when all the other stuff happens such that the ice actually melts; which can actually happen before Spring.

47
Arctic sea ice / Re: Stupid Questions :o
« on: April 07, 2017, 02:18:07 PM »



Based on incoming insolation and Outgoing Longwave Radiation (OLR), I'd say the equilibrium point is between the last week of March and mid-April depending upon which arctic latitude we want to look at.


Interesting, and I think might be close to answering the real question.  If I assume the thermal conductivity of ice at 0C is the point at which irradiance would start to melt the surface of the ice, and if I am correct in interpreting the 2.20 in the table in the link below as the same as 220 in your graphs then it would give about the same result  as you have suggested for total OLR.

http://www.engineeringtoolbox.com/ice-thermal-properties-d_576.html

The difference being that I think real dates could be assigned (with enough thought) for when the Sun is hot enough to start melting the ice.

Am I at all close here?

48
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: April 06, 2017, 08:09:23 PM »
Greenland sheet contains about 3 million km3 of ice. That might be enough for keeping some chill around, and those ~1000 km3 of "virtually ice-free" Arctic thru summer
If it doesn't decide to float south...in chunks.

49
Arctic sea ice / Re: Stupid Questions :o
« on: April 06, 2017, 06:43:58 PM »

Yep, water is no blackbody. Nor is ice. The atmosphere makes this a tricky question.


Make simplyfying assumptions as necessary. I was trying to throw weather out, where possible.  Pick your favorite weather, average the weather, whatever makes the calculation easy.

I'm looking for a ballpark figure; when the sun is enough on its own to keep the water open. I really don't have a sense of it.

You can always cheat and use observations; we have pretty good observations of temperature of outbound (as measured by satellite), a pretty good sense of albedo (I did suggest open water), and a little internet digging will give you the incident (I know they exist, though I was't having much luck finding a good one).  It's true that observations are prone to all sorts of variables (most notably clouds) but it should be a decent ballpark.

By early May, the insolation for north pole crosses the incident of the equator so certainly it's somewhere sooner than that. At equinox it's 0W incident, so it's later than that. It gives about a 50 day range; I'd say probably it's between April 1 and May 10 just based on that information.

Since I too would love to see some sort of table providing the basic information, let me try to explain what is wanted.  Here in New England in about Mid-March after a snow storm even on cold days the Sun is "hot" enough to melt the snow during the day.  You can have all sorts of other things going on, but by basic seasonality at some date for a given latitude the Sun shines bright enough that the dirt (ice) can't keep things from melting.  A storm can, but not the surface.

50
Arctic sea ice / Re: The 2017 melting season
« on: April 05, 2017, 11:21:10 PM »
Regarding DMI's 80N temps, the forecast as posted by romett seems to imply that temps are generally expected to drop in the next few days. Who knows, we might get that climatology hug after all. Although even if we do, the FDD damage has already been done, as can also be seen in the latest PIOMAS numbers.
I assume it's got to happen eventually.  We are not out of ice up there yet.  But the gap between where we are and where we used to be at this time of year is really obvious.  We are still seeing the switch at the end of 2015, and no backsliding.

I might change my mind and expect summertime temps to jump above the climatology sometime late this summer.

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