679 replies to this topic

[jethro]

I don't really follow the Arctic ice thread much so apologies if this has been covered already...

I always understood that the biggest problem with greater ice loss in the summer was the change to albedo, in that dark ocean water absorbs more energy from the Sun than ice which reflects. This in turn would lead to warmer oceans, leading to ever more ice melt, so on and so forth until it's all gone.

If this is the case, then the date for the start of re-freezing in the autumn should be delayed to allow for the warmer oceans to cool enough to begin freezing.

Has the start date of re-freeze been getting later?

[Gray-Wolf]

Captain_Bobski, on 05 October 2009 - 08:03 , said:

Are you suggesting that we shouldn't be happy when end-of-summer ice extent improves, or when the winter high extent improves? You do seem determined to find the worst in every situation, GW.

CB

Sorry C-Bob, I suppose you could interpret my posts that way. It is not that I don't see the positives but they are always qualified by 'the bigger picture'.

It's kinda like folk pointing out weather and me seeing only climate.

Sadly since the 1980 Arctic max. the 'trend' has been in one direction only and even the 'positives' you point us to are but a continuation of that trend.

I'd love to peep 30yrs down the line and see that the past 2 years increases (over the terrible 07' min.) continue but it seems (to me) that we have a long ways to go to overturn the overall trend of wastage in the Arctic.

Even when 'weather' is favourable for retention we still seem to fall in with the continued 'trend' for loss across the arctic (see the past 2 years with high winter max figures for a start point and 'favourable' conditions through the summer melt for retention).

As with global climate I wouldn't want to hold a natural 'extreme' as the benchmark from which to measure all else (be it 98' global temps and all the chatter it generates or the 07' ice extent min. and the chatter this generates) better to take the smoother line of the 'long view'?

'One Swallow a summer does not make' and for every positive I glean from the daily onslaught of reports/data/papers there are many negatives confirming (to me) that we are in a bad place and that both our understanding of that 'bad place' increases and the data showing us this 'bad place' amasses.

I would hope ,for my kids sakes, that we do have nothing but positives to look forward to but is this realistic of me to expect? When they ask questions of me do I try and have them understand the picture as it is painted or give them my hopes for the future?

For those who question CO2's role in our current warming do they also question it's part in the acidification of our oceans? The latest paper on the acidification of the Arctic waters surely makes us question the wisdom of adding such quantities of the gas into our atmosphere even if only for the impacts on the ocean's ecosystems?

Edited by Gray-Wolf, 05 October 2009 - 08:53 .

[Gray-Wolf]

jethro, on 05 October 2009 - 08:29 , said:

I don't really follow the Arctic ice thread much so apologies if this has been covered already...

I always understood that the biggest problem with greater ice loss in the summer was the change to albedo, in that dark ocean water absorbs more energy from the Sun than ice which reflects. This in turn would lead to warmer oceans, leading to ever more ice melt, so on and so forth until it's all gone.

If this is the case, then the date for the start of re-freezing in the autumn should be delayed to allow for the warmer oceans to cool enough to begin freezing.

Has the start date of re-freeze been getting later?

I think you'd need to view this sector by sector as the distribution of ice cover varies (due to weather) over summer. The areas I'd look to would be those to the rear of Bering and off the Russia coast as these appear to be where we have lost 'traditional' summer ice cover. Also the heat accrued over summer is radiated out into the atmosphere in autumn and the measures of the 'Arctic Amplification' are best witnessed by the temp profiles of the atmosphere above the summer 'open waters' as compared to the past measures of the temp profiles there.

[jethro]

I appreciate that weather plays a huge role in the ice loss, that was the primary cause for the phenomenal melt in 2007. Wind plays a major role too, flushing old, multi-year ice out into warmer waters, this has more to do with the state of the AO and the NAO than anything else. Surely the proposed positive feedback loop whereby less ice leads to loss of albedo, leading in turn to warmer oceans and even less ice, should first be noticeable in the start date of re-freeze?

It doesn't matter what the summer atmospheric temperatures are, ice has always melted in the summer. What matters is if this is leading to warmer ocean temperatures, this would indicate a later start date for re-freeze; has it been getting later?

[Gray-Wolf]

http://nsidc.org/mon...august2009.html

All I can do is point you at the NSDIC overview.Hope this is useful?

http://www.the-cryos...-2008-print.pdf

and the paper that the Arcticle refers to.

[pyrotech]

Gray-Wolf, on 05 October 2009 - 08:41 , said:

Sorry C-Bob, I suppose you could interpret my posts that way. It is not that I don't see the positives but they are always qualified by 'the bigger picture'.

It's kinda like folk pointing out weather and me seeing only climate.

Sadly since the 1980 Arctic max. the 'trend' has been in one direction only and even the 'positives' you point us to are but a continuation of that trend.

I'd love to peep 30yrs down the line and see that the past 2 years increases (over the terrible 07' min.) continue but it seems (to me) that we have a long ways to go to overturn the overall trend of wastage in the Arctic.

Even when 'weather' is favourable for retention we still seem to fall in with the continued 'trend' for loss across the arctic (see the past 2 years with high winter max figures for a start point and 'favourable' conditions through the summer melt for retention).

As with global climate I wouldn't want to hold a natural 'extreme' as the benchmark from which to measure all else (be it 98' global temps and all the chatter it generates or the 07' ice extent min. and the chatter this generates) better to take the smoother line of the 'long view'?

'One Swallow a summer does not make' and for every positive I glean from the daily onslaught of reports/data/papers there are many negatives confirming (to me) that we are in a bad place and that both our understanding of that 'bad place' increases and the data showing us this 'bad place' amasses.

I would hope ,for my kids sakes, that we do have nothing but positives to look forward to but is this realistic of me to expect? When they ask questions of me do I try and have them understand the picture as it is painted or give them my hopes for the future?

For those who question CO2's role in our current warming do they also question it's part in the acidification of our oceans? The latest paper on the acidification of the Arctic waters surely makes us question the wisdom of adding such quantities of the gas into our atmosphere even if only for the impacts on the ocean's ecosystems?

Can not argue with you quote 'one swallow a summer does not make', however we also need to understand that if a turnaround on global temperatures has now slowly just began, that will then lead to Artic sea ice recovering, then perhaps we should also use the quote, 'Rome was not built in a day'
Firstly human intervention on this planet will obviously effect it to some degree, Co2 and other pollutants should be reduced and in doing so can only be a positive move. BUT why do we find a piece of a puzzle then sit back and think we have the full picture. The Sun has the biggest effect on our planet, Nothing else has an effect anywhere near to the effects the sun does.
so with a long period of excessive solar activity would you not expect temperatures to rise, now we enter a much less active period and so we would expect temperatures to fall. Which is exactly what has happened. Sea ice minimum was just behind the solar max and sea ice recovery starts with the minimum solar activity( using the time lag )
To explain the effects of CO2 we would be looking for a drop in levels for the last two years, Howver that has not happened, CO2 ammounts have increased. The only change is too the solar cycle.
For the recovery of sea ice we now need to look at the depth and length of this current minimum.
Short mimimum and return to a maximum would return sea ice depletion to what we have witnessed for last decade, continued mimimum would recover the ice like has happened in the past.
So whats the weather forecast for the sun? truth is everyone is guessing. Some experts predict a Maunder mimimum, others are more causioulsy predicting a Dalton mimimum. Some even say w will return to high solar activity very soon.

I cover this further in another thread so will not repeat it here, but i enclude the link to it and some links to articles about our current minimum and the Dalton minimum.
If some one wants to explain why sea ice has slowly recovered for last two years, and explain why if CO2 is biggest cause then please do.
Its the solar cycle that is why, its happened before and will again.
If you look at how much ice has recovered then it does not look impressive but are you looking acurately at what has happened?
You see 300000 km2 extra ice not dissapeared this year from 07
But in 07 there was an increas in ice loss from 06 - correct? lets say again 300000 km2 less.
So the turn around is much greater its the 300000 that is actual improvement plus the 300000 that was expected in the pattern. The temperatures and other factors causing that loss needed to firstly drop signifigantly to stop any further loss from 300000 - zero. Then the effects had to be more again to make an increase in sea ice. Looking at it from that perspective w really have seen an amazing turn around.

http://wattsupwithth...at-is-possible/

http://wattsupwithth...orner-for-2009/

Here is a link to netweather forum UK and Western Europe where its explained and debated did not want to put it here as this is about Sea ice but the above is releavant as its the cause of the loss and recovery
http://www.netweathe...ge/page__st__34

To finish can i reiterate that CO2 is not good for our planet and we should do what we can to look after our planet, just do not think its had as much effect in this area as some people thought. The cause has been shining down on us, perhaps we were temporarily blinded by it.

Edited by pyrotech, 05 October 2009 - 10:34 .

[jethro]

Thanks for those GW.

They do indeed confirm that later re-freeze would be symptomatic of amplification.

"As the climate warms, the summer melt season lengthens and intensifies, leading to less sea ice at summer’s end. Summertime absorption of solar energy in expanding open water areas increases the sensible heat content of the ocean. Ice formation in autumn and winter, important for insulating the warm ocean from the cooling atmosphere is delayed."


However, as always, nothing's simple in any of this.

"Less sea ice at summer’s end (September), as observed, has enhanced upward heat fluxes
to the atmosphere. Further analysis of the NCEP data reveals that the rise in Arctic
Ocean SAT in autumn is most closely associated with an increase in longwave radiation
emitted by the surface, with changes in the turbulent sensible and latent heat fluxes playing a lesser role. Interestingly, the autumn net surface heat flux has shown little
coherent change in the past decade. This follows in that while the warmer atmosphere
radiates more strongly to the surface (by itself contributing to a more positive net surface
heat flux), the surface in turn radiates more strongly to the atmosphere, with an
opposing effect."

Does any one know if a later start date to the re-freeze is/has been occurring?

[Iceberg]

There is certaintly a later start date than in previous decades which once saw late August as a valid time for ice to start recovering.

However this isn't a detailed enough answer and more questions such as (what constitutes sea ice recovery (an increase of 100Kskm or 1Mskm) and at what point in the past are we comparing to ?.

The fact that we are currently below 6Mskm still might be enough reason to assume that even in October ice hasn't really started to recover properly yet.

[jethro]

I think the fairest assessment date would be when we stop recording losses and start recording gains.

This would answer the question of whether the time it takes for latent heat to be lost from the oceans, to the point that freezing is possible is/has been delayed - warmer oceans due to loss of albedo, taking longer to cool in the Autumn.

[Iceberg]

It's a good suggestion, but I think the problem is that small gains can easily come by ice consolidation(with out ice forming in the warmer waters).

This year is a good example of where the ice is so far recovering pretty dreadfully, this could be down to warmer SST's but might be down to other factors.
We stopped recording ice losses many days ago, but I wouldn't yet say that ice is really recovering.

However going from what you've said I don't believe that ice has stopped falling in August in the last 9 years, however in the 70's and 80's I believe this did happen.

This date is much more likely to be in the later half of September now.

[Gray-Wolf]

The problem in that J (as I see it) is that over autumn the net gains start to amount to more than the losses. We don't get a single line where loss ends and gains begin. Last year we were well into net gains whilst old perennial was still being lost to the Atlantic (into Nov.).

Again we'd have to look at things area by area and see how much ice cover it held through summer and then compare this with past years when less ocean was exposed (and then cross reference all of this with the weather conditions for each year so as not to confuse general 'weather' oscillations with 'climatic trends')

If the current trend continues, and the Arctic amplification becomes a major signal (in line line with the models predictions), then this will be a much easier task.

As it is we are only just beginning to amass the data (over the past 8 years) that shows that the phenomena is starting to occur (ahead of times it would appear) so maybe it would be better to wait until we see a stronger signal to get a data set of more meaningful results which are not open to interpretation?

For me the fact that we can see the atmospheric indicators of the process is enough to have me concerned esp. as it is so far in advance of the 'predicted' onset.

As an aside I have to wonder what impact the measurable atmospheric changes have on the local weather? I mean if temps aloft are being un-naturally warmed surely this impacts upon the weather folk experience at ground level?

I read recently of the plight of the Caribou/Reindeer (not just the dramatic loss in numbers) and their herders who are having to buy in fodder as freezing rains make their normally available food unreachable, surely this is a 'new' phenomena?

http://www.google.co...N4KOXQD9B4MUK81

Edited by Gray-Wolf, 05 October 2009 - 12:12 .

[jethro]

I've been trying to find information to answer my own question but I'm not having any success.

All the info focusses upon extent of melt and re-freeze but can't find anything referring to annual date of minimum. Given that NSIDC say this:

" Because of the variability of sea ice at this time of year, the National Snow and Ice Data Center determines the minimum using a five-day running mean value. We have now seen four days of gains in extent. It is still possible that ice extent could fall slightly, because of either further melting or a contraction in the area of the pack due to the motion of the ice. When all the data for September are in, we will confirm the minimum ice extent for the season. "

There has to be an archive somewhere of the determined minimum dates.

[Gray-Wolf]

Maybe you'll only gain partial answers? the Canadian sea ice folk must keep archives but I imagine that this will be in very localised areas and not across the entire Arctic basin?

[BUSHY]

With regard to earlier posts on ice thickness etc.
"Another focal point of the campaign were large-scale measurements of ice thickness in the inner Arctic, which were conducted in close collaboration of the Alfred Wegener Institute together with the University of Alberta. An ice-thickness sensor, the so-called EM-Bird, was put into operation under a plane for the first time ever. To conduct the measurements, Polar 5 dragged the sensor which was attached to a steel cable of eighty metres length in a height of twenty metres over the ice cover. Multiple flights northwards from various stations showed an ice thickness between 2.5 (two years old ice in the vicinity of the North Pole) and 4 metres (perennial ice in Canadian offshore regions). All in all, the ice was somewhat thicker than during the last years in the same regions, which leads to the conclusion that Arctic ice cover recovers temporarily. The researchers found the thickest ice with a thickness of 15 metres along the northern coast of Ellesmere Island."
http://www.research-...geId=12354.html

[jethro]

Gray-Wolf, on 05 October 2009 - 13:32 , said:

Maybe you'll only gain partial answers? the Canadian sea ice folk must keep archives but I imagine that this will be in very localised areas and not across the entire Arctic basin?

Maybe you're right GW, seems odd though.

There's been so much focus upon ice loss and polar amplification of AGW due to loss of albedo, you'd have thought a very basic thing such as determined minimum date would have been easier to find. It would be such a graphic demonstration of the expected problems, if it could be shown re-freeze was occurring at an increasingly later date every year. Perhaps it isn't? What would that say about the expected amplification?

Can't understand how a decision that ice minimum has been reached for the Arctic basin every year can be made and yet archives would be localised, NSIDC would need to collate that local info to reach their decision.

[Iceberg]

This is interesting.

http://commons.wikim...tic_Sea_ice.png

I've found this site

http://svs.gsfc.nasa...3563/index.html

and plotted from 1979 to 2007 below, sorry it's so quick I need to go home !.

Graph

Attached Thumbnails

• 
• 

[doctormog]

Interesting images. It's noteworthy that the melt onset was so much earlier in July 2008 yet the minimum was significantly higher than the previous year. Just goes to show that there are few direct relationships re. Arctic ice melt.

[jethro]

Thanks for that Iceberg.

I find the illustration confusing, it would appear melt from the fringes hasn't been getting earlier, which isn't what you'd expect from warming oceans really.

From the other link it would appear determined minimum has been anything from 21st September in 1979 to 14th September in 2008 - this year should come in about average.

The earliest it has started to re-freeze was 2nd September back in 1987, the latest the 1st October in 1995, curiously 1998 when you'd have expected a late re-freeze due to the mega El Nino, it was the 12th September, bang on average.

It seems to my amateur eyes that the expected amplification due to loss of albedo, leading to warmer oceans and more melt, isn't happening. Yes, there's less ice than there used to be, yes it's thinner but I've got to ask how important is this if it re-freezes as usual every year?

[Gray-Wolf]

???

The fringes would be the first areas to respond wouldn't they? So why have they already not responded and we are now viewing the 'changes' occurring deeper within the pack?

Freezing water of variable salinity/temp is difficult to gauge. Gauging the melt just means temps above 0c does it not? Simpuls....squeeaks

EDIT: I think it a great mistake to look at the final phase of ice loss , it's move from ice to open water, to be viewed as the whole picture.

Sketchy records log the reduction in thickness across the pole from at least the 1950's.

If we accept the data we are accruing today then any changes we can measure globally were occurring at 3 times the speed across the poles.

By the time sat, data became available the first phases of arctic melt were surely well over?

Your search for early melt times at the fringes would surely be a thing of the late 60's early 70's and sadly folk were not as keen on recording those same changes as they are today.

Your question, J, possibly unlocks another side of the changes in the Arctic being when could we have seen the initial warning signs?

As you have stated on another thread AGW is a matter of retrospect. Nobody seems willing to accept anything unless 100% proven and that only occurs after the event. Sadly that mentality will not help save those that predictive action would.

Edited by Gray-Wolf, 05 October 2009 - 21:23 .

[jethro]

Er no.

As far as I'm aware (according to many links which have been posted here over the last three years) there was a sustained period of ice growth and expansion during the 1960's and '70's; so much so, that talk of the time was of another impending ice age.

Ice melt is supposed to lead to a reduction in albedo, leading to warmer oceans, leading to less and less ice, the earliest symptom of which is later onset of re-freeze; the links you kindly posted earlier today confirmed that.

To date, according to the links Iceberg posted, later onset re-freeze is not occurring despite the dramatic loss of ice.

This has nothing to do with acceptance or otherwise of AGW, it's simply trying to understand the dynamics at work here because things are not going according to the script. What are we missing? What signals/symptoms have we mis-interpreted?

Predictive action is all well and good if you're certain of cause and effect, if you're not then it's all just a shot in the dark and whilst you're busy thinking you're doing the right thing, you might miss something immensely important and makes a bad situation worse.

In the words of a very good carpenter friend of mine "measure twice, cut once", we're not done measuring by a long way.