679 replies to this topic

[Jackone]

This is the new thread for the Autumn Winter Ice Recovery Phase.

 Arctic Ice Summer 2009.xls   351.5K   186 downloads This is the final spreadsheet showing the Summer Ice Position.

 Arctic Ice Autumn 2009.xls   301.5K   223 downloads This is the first Autumnal update for the season and this will be updated regularly.

[yeahbabyyeah]

JACKONE, on 01 October 2009 - 21:14 , said:

This is the new thread for the Autumn Winter Ice Recovery Phase.

Arctic Ice Summer 2009.xls This is the final spreadsheet showing the Summer Ice Position.

Arctic Ice Autumn 2009.xls This is the first Autumnal update for the season and this will be updated regularly.

Why is there such concern over the ice melt etc when it doesnt look as bad as the media and world governments think it is? Looking over the past 6 years it looks pretty average to me

[sunny starry skies]

yeahbabyyeah, on 02 October 2009 - 10:35 , said:

Why is there such concern over the ice melt etc when it doesnt look as bad as the media and world governments think it is? Looking over the past 6 years it looks pretty average to me

The problem is that the last six years are all remarkably low in relation to longer-term data.



As seen at http://nsidc.org/arcticseaicenews/ the 2009 minimum is 24% below the long-term average, which is an awful lot of white shininess lost from the top of the world. Also, a lot of the more stable multi-year ice was lost in 2007. We can only hope that in future years the levels can recover, but you can see the long-term interannual trend in minima (to 2007) below...

{EDIT: Graph to 2007 removed - updated graph to 2009 posted by pottyprof below}

Figures from NSIDC.
sss

Attached Thumbnails

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Edited by sunny starry skies, 02 October 2009 - 14:48 .

[pottyprof]

Well.. We can show a current NSIDC graph..



As with the 1998 temperature graph, there has to be a high point/low point and showing one that isn't current, doesn't give the whole picture. Agreed, the amount of ice is still on a downward trend but there is a glimmer of hope.

[sunny starry skies]

cheers for providing the updated graph pottyprof - it is always relevant to provide the up-to-date data, and I didn't manage to find it. There's a wee glimmer of hope in the last two years' sea ice values, but I'll want to see a continued recovery and more multiyear ice before I'll start counting the swallows and declaring the season. Re 1998 temps - it's clear that 1998 was an outlier in the continued warming trend, as 1980/1981 and 1990, or as 1976 was a cooler outlier. The whole picture of temperatures is still an upward trend though...

[Jackone]

Just to point out that sunny starry skies is correct, the average of the past 6 years are well below the 30 years averages.

[Snow White]

JACKONE, on 02 October 2009 - 19:25 , said:

Just to point out that sunny starry skies is correct, the average of the past 6 years are well below the 30 years averages.

Just out of curiosity - what is the past 6 years average if you discount 2007 ?

Also - Ice extent seems to be increasing faster now after the lull after the minimum was reached.

[badboy657]

http://in.reuters.co...E5916OP20091002

just found this.

its not good no freeze happening yet worring indeed.

Edited by badboy657, 03 October 2009 - 00:49 .

[Snow White]

badboy657, on 03 October 2009 - 00:41 , said:

http://in.reuters.co...E5916OP20091002

just found this.

its not good no freeze happening yet worring indeed.

http://arctic.atmos.....region.11.html

As the graph shows sea ice in the Beaufort Sea is doing reasonably well so Id have to treat that report with a pinch of salt.

Edited by Snow White, 03 October 2009 - 06:00 .

[Snow White]

Snow White, on 03 October 2009 - 00:14 , said:

Also - Ice extent seems to be increasing faster now after the lull after the minimum was reached.

http://www.ijis.iarc...aice_extent.htm

[Iceberg]

badboy657, on 03 October 2009 - 00:41 , said:

http://in.reuters.co...E5916OP20091002

just found this.

its not good no freeze happening yet worring indeed.

This is talking about the older thicker multi year ice, which isn't shown in any of the two graphs just posted and along with the decline in extent over the last 5 years is a major issue in the Arctic.

[Snow White]

Iceberg, on 03 October 2009 - 06:42 , said:

This is talking about the older thicker multi year ice, which isn't shown in any of the two graphs just posted and along with the decline in extent over the last 5 years is a major issue in the Arctic.

Yes the downward trend is a major issue, however both of the graphs I gave a link to combine both multi year and and first year ice. I don't think there are any graphs which just show multi year ice however this link gives us some idea of concentration / thickness - http://arctic.atmos....e.color.000.png

After the record loss of 2007 if we were going to see any increase from that minimum (which we have) it would of had to of been first year ice anyhow, and now after a second year of improvement the ice will be even stronger.

Edited by Snow White, 03 October 2009 - 07:03 .

[Iceberg]

Sorry snow white, just to clear it up, neither of those graphs are any good at looking at multi year ice, multi year ice might be 0% or 100% on those graphs or anything in between.

The AMRSE data does give you an idea of concentration but concentration is again of no relavence of ice thickness. You might have a unbroken layer of ice 20 cm thick or broken up ice at 25% with a thickness of 2M.

The only problem is that since 2007 the thick older ice has been in rapid decline, (it was in decline before that as well).

[Snow White]

Iceberg, on 03 October 2009 - 07:13 , said:

Sorry snow white, just to clear it up, neither of those graphs are any good at looking at multi year ice, multi year ice might be 0% or 100% on those graphs or anything in between.

The AMRSE data does give you an idea of concentration but concentration is again of no relavence of ice thickness. You might have a unbroken layer of ice 20 cm thick or broken up ice at 25% with a thickness of 2M.

The only problem is that since 2007 the thick older ice has been in rapid decline, (it was in decline before that as well).

Sorry I don't think you understand, I did not say the graphs were any good for looking at multi year ice, the graphs show sea ice extent / area which is all kinds of ice (1st year, 2nd year, 10th year etc).

If 'since 2007 the the thick older ice has been in rapid decline' why has there been an INCREASE in the minimum for the past two years ?

Am sorry Iceberg but your not making sense and I do not want to clog up the thread trying to get through to you !!!

[Iceberg]

Snow white, your right I am very confused, but 2 posts isn't clogging up a thread and this is an important discussion on the state of the Arctic. People might well look at the extent see it improving and think that everything is OK.

If we take this back to the point I made.
A report on multi year ice by a sea-ice expert with the U.S. National Oceanic and Atmospheric Administration with many years of knowledge can be dismissed in your opinion and you posted up a graph to say that things are going reasonably well as opposed to what he's saying.

You then said that the graphs do show multi year ice and then finally said that the graphs are no good at looking at multi year ice and that I am just not getting what your saying, (If the graphs are no at looking at multi year ice, why mention them with an article on multi year ice saying take it with a pinch of salt)

Ice extent can increase, but ice thickness can go down as can the amount of older ice.(If the amount of first year ice is the ice that is growing.)

On the summer Arctic thread I posted images from NOAA/NSIDC which clearly showed the loss of older ice after the summers of 2007 and 2008, the 2009 data should be out in the next week or so. This data isn't perfect, but if we can't trust the people that fly over the ice in planes year on year examining the ice who can we trust ?.

I am not trying to be argumentative but I really don't get what your saying and why you want to dismiss the report mentioned.
I am happy to leave it here though as I agree that two people going backwards and forwards might be boring for people.

[Jackone]

Iceberg, on 03 October 2009 - 08:08 , said:

On the summer Arctic thread I posted images from NOAA/NSIDC which clearly showed the loss of older ice after the summers of 2007 and 2008, the 2009 data should be out in the next week or so. This data isn't perfect, but if we can't trust the people that fly over the ice in planes year on year examining the ice who can we trust ?.

Certainly looking forward to that.

badboy657, on 03 October 2009 - 00:41 , said:

http://in.reuters.co...E5916OP20091002

To be honest, this report doesn't really say anything that any we didn't know, the important thing which should come out is amount of multi year this year compared to recent years, and this isn't given any data at all.

There is a danger with articles like this in that they spin old data, when the data should be allowed to speak for itself.

[doctormog]

Here's a question. If the ice doesn't melt does it matter what age it is?

If the ice extent minimum continues to increase over the next couple of years the age of the ice will be relatively irrelevant except in terms of statistics. There was AFAIK more ice in the Beaufort Sea area than in the last two years despite the age of the ice.


What seems to be repeated continually is that as well as a record minimum in 2007, there is now significantly more single year ice. The latter information is totally superfluous.

If there is less ice than there has been there will always be more single year ice the next year. There's no point in stating this as extra evidence it's not it's a consequence of the previous year's ice melt not anything else.

[Iceberg]

Michael, the difference between single year and multi year ice does matter for the reasons that the expert gave.

"The one-year ice that accounts for the increase over 2007 and 2008 -- pancake-flat pieces with finger-like surface ridges etched by movements of the water -- is no substitute for the thick multiyear ice, Overland said.

"It's thinner. It's more broken up. And it moves faster," he said. "And all of that contributes to melting earlier in the season."

We are saying that since 2007 there is more single ice, but we are also saying that there is less older ice (not just as a percentage), both myself and GW have been saying this for ages now, with this article we have an ice expert at NOAA saying it as well.

He is talking about a specific are in the Arctic and we certiantly can't extrapolate from this, but his comments about the lack of multi year ice are reinforced by his CURRENT observations from the coast guard plane.

I am not saying there is any earth shattering revelations, just that why can it be taken with a pinch of salt ?.

[doctormog]

With respect that does not answer my question, I know the difference between first year ice and older ice. If the first year ice does not melt in the melt seaosn it doesn't matter what age it is as next year it will be 2 year old ice etc.

If there is more ice at the minimum this year than last there is potentially more second year+ ice too. If not it suggests that that some of the first year ice from the previous year lastted better than some of the older ice. The bottom line is the minimum area/extent not the age. You could use one as the predictor of the other I guess but based on that the 2008 minimum would have been lower than 2007.

Yes, perhaps it's an indicator but it's significantly outweighed by weather conditions as the last 2 years demonstrate.

I've not mentioned taking things with a pinch of salt and I don't especially question the experts' opinion but the data in terms of the last 2 years' minima v the one year ice (i.e. an increase of the former and a increase in the latter) suggest it's not exactly an inversely proportional relational and that other factors may be more dominant.

So ice age is an interesting factor but not the over-riding one and the amounts of single year ice should be reasonably easy to predict based on the extent and location of ice melt combined with the movement from the preceeding season. Not rocket science and not another factor in a downward spiral, just another symptom of the last few years.

[Iceberg]

I completely disagree Michael, Many experts suggest that the reason we have the mass melt in 2007 is that the older ice had been steadily eroded before that date to allow the ice no protection when a good melt year came along.

The age of the ice is sensibly looked at after the summer season as it shows how much older ice is left. Potentially is the important word there there might be there might not be .

The age of the ice is an important indicator as to the fragility of the ice, a Recovery of ice extent without a recovery of older ice can be swept away by a good melt year. This is why it's important.

Of course synoptics are very very important, but I wouldn't want to rely soley on synoptics to improve the ice over the next few years.