Arctic Ice

[Gray-Wolf]

And I think that that's the nub Iceberg.

Last years record losses where put down to a conflagration of differing phenomena that all aided in the record loss.

This year the Arctic has shown more 'average' conditions and yet still we are already looking to be the second lowest amount of sea ice in the Arctic come seasons end.

The switch from a majority perennial ice in the Arctic to majority 'single year' ice is the real killer here.

With a slowed pack re-form in autumn and an ever earlier 'start' to the melt season I can see no way (Barring a nuclear winter!!) of ice re-build in the near future.

Yes the pedant's will argue over lines on graphs but the trend is definitely set and that trend is the continued erosion of perennial ice until it is only located in favoured 'micro-climatic' enclaves and the whole arctic covered in very fragile,mobile single year ice over winter.

By the end of this progression even a 'cold' summer will still leave the Arctic effectively ice free come the start of September.

[osmposm]

It's not worth tearing to bits it's just wrong. But hear are a few graphs that prove how wrong.

BTW the deep NW passage open today, the NE passage will open in the next 4 days and large chunks of the Arctic ice are opening up near the pole.

I think you're jumping the gun again re the deep NW passage, Iceberg, I don't think you can call it properly open yet. I find the zoomed & false-colour version of the Bremen images more useful, it seems to be easier to spot smaller (but still significant) ice areas on it: http://www.iup.uni-bremen.de:8084/amsr/Nor...Passage_nic.png

As I surmised a little while ago, the northern side of the passage has largely cleared as the ice within it has been pushed south up against the shores of Victoria & Prince of Wales Islands. However, there's apparently blocking ice still around in Viscount Melville Sound......and could possibly continue to be, since a stream of ice seems to be drifting down into it, east of Melville Island. There also seems to be more ice around than a day or two ago at the western end of the passage, again apparently because lots of looser ice is also drifting south past the west side of Prince Patrick Island. Here is a zoomed and rotated version of the latest Bremen false-colour image...I've added white arrows to show what I mean:

It would be ironic if the mobility and southwards drift of the ice breaking up north of the passage were to prevent its proper opening!

Edited August 17, 2008 by osmposm

[Chris Knight]

I think you're jumping the gun again re the deep NW passage, Iceberg, I don't think you can call it properly open yet. I find the zoomed & false-colour version of the Bremen images more useful, it seems to be easier to spot smaller (but still significant) ice areas on it: http://www.iup.uni-bremen.de:8084/amsr/Nor...Passage_nic.png

As I surmised a little while ago, the northern side of the passage has largely cleared as the ice within it has been pushed south up against the shores of Victoria & Prince of Wales Islands. However, there's apparently blocking ice still around in Viscount Melville Sound......and could possibly continue to be, since a stream of it seems to be drifting down into it, east of Melville Island. There also seems to be more ice around than a day or two ago at the western end of the passage, again apparently because lots of looser ice is also drifting south past the west side of Prince Patrick Island. Here is a zoomed and rotated version of the latest Bremen false-colour image...I've added white arrows to show what I mean:

It would be ironic if the mobility and southwards drift of the ice breaking up north of the passage were to prevent its proper opening!

The thing is that there is no fast ice anywhere in the Arctic anywhere except the most northerly Ellesmere coastline, and its nearest, northerly islands. All else is drift. With a fast enough boat, not an icebreaker, the north pole could be circumnavigated today, and in the next week or so, surely unprecedented.

Edited August 17, 2008 by Chris Knight

[osmposm]

The thing is that there is no fast ice anywhere in the Arctic anywhere except the most northerly Ellesmere coastline, and its nearest, northerly islands. All else is drift. With a fast enough boat, not an icebreaker, the north pole could be circumnavigated today, and in the next week or so, surely unprecedented.

Absolutely, Chris. But Iceberg generally makes clear that he is talking of clear water and a simple passage for most ships (at least I think I've understood that right). And besides, I'm slightly playing devil's advocate here lest some less objective nitpicker makes too much of it.

I absolutely accept that the situation is extraordinary, almost certainly unprecedented in recent human history, and very worrying. And even if, as I think possible, the broken-up ice drifting down from the north makes the deep NW passage unnavigable for the time being, it merely presages an even more alarmingly ice-free future.

Edited August 17, 2008 by osmposm

[J10]

No there isn't Jackone, sorry.

I posted up the Bremen picture because it's a) the most upto date and :lol: , the highest resolution that I could find.

Here are the CT(although for the day before) and the IJIS(a lower res picture) which show the same thing (I believe this covers most of the sites commonally used here.)

I can only find sites that show it either open or almost open except for a tiny bit of broken up ice.

I spent over an hour looking for a relavent modis,aqua, landsat image and failed to find one.

The problem is that people don't have time to trawl though every piece of evidence, save it down, post it up etc. So it's quite fair to use the sites that we use frequently, i.e Bremen, CT, NSIC and IJIS and report what they are saying.

There are CT's old pictures, but he openly admits that they are not as good as the AMRS-E ones.

I completely understand what your saying and think that you are right you should always try to show balance, or admit that what your reporting is only one view.

Well I have looked at different sites on the internet and even on the same sites Crysosphere today, different charts show different things. So your chart shows mainly Ice free while mine shows a different story even on the same day.

So there are charts which show different things on the internet, and this makes the whole thing confusing.

I am not saying which are the most accurate, and if the old CT ones which you maybe referring to are slightly not "high res", so where are the comparison charts for these new ones, and if these charts are inaccurate then why are they still being used and posted onto the internet.

I am trying to get to the facts in relation to the situation and as a result I am publishing the figures on the Ice regardless on whether they are falling quickly or slowly.

Current Position Based on the figures I have been regularly updating, as on 16th August (Figures in sqkm2)

2003 :6640313

2004 :6611250

2005 :6100156

2006: 6339219

2007: 5241406

2008: 5910000

currently well above 2007, below 2005 and well below every other year. The projection is for the year low figure to be below 2005 but well above 2007, I will continue to update this about twice a week until the year end figure is reached whenever that may be.

[BLAST FROM THE PAST]

And I think that that's the nub Iceberg.

Last years record losses where put down to a conflagration of differing phenomena that all aided in the record loss.

This year the Arctic has shown more 'average' conditions and yet still we are already looking to be the second lowest amount of sea ice in the Arctic come seasons end.

Clearly then that it is AGW, as temps are normal there's more melt? Must be getting warmer :lol:

BFTP

[Roger J Smith]

I think that distribution of currents in the sub-polar seas and the Arctic Ocean where it opens up, have always been at least the equal of temperature regimes, as far as determining how each ice-melt season will actually progress. Wind is also a big factor in redistributing ice as it breaks up.

We'll have to see what happens this next winter season with the rebound effect from what is bound to be a pretty extensive meltdown north of Siberia before October comes with its usual rapid cooling trend north of 60 N.

Last year our speculation proved accurate that there would be consequences and only Europe failed to get in on the rebound dividends, so to speak, if you like your winters cold and snowy, that is.

If the anomaly is centered further west this season, then could the rebound perhaps be less intense in North America and open up some possibility for Europe to share with Asia?

Anyway, this is my orientation towards the question, I am not inherently biased towards large or small ice-melt anomalies because it seems that average ice melt is perhaps the least promising scenario for cold winters in Europe, small ice-melt must be correlated with cold regimes in general, and large ice-melt could bring in the rebound from sudden onset of snowy winter conditions in potential source regions for your arctic highs (up around Nov Zem and the Kara Sea). So fingers crossed, melt all you wish, Siberian ice, it's all good. :lol:

[jethro]

The problem with the debate is that very few of those opposed to the views of Iceberg, Gray-Wulff et al ever post at all, and when they do it is usually very briefly, and with (in my view) no coherent arguments. All too often it's just links to images with little or no proper comment (let alone analysis), to websites with an agenda, or to stories of limited relevance about people who've managed to dodge their way through the NW passage in the past. (The 'hyper-melters' can be guilty of this, too, but not so consistently.)

Ossie

Ahem...Polyakov papers. Not brief, not incoherent, no agenda, propaganda or drivel; no comment from the "hyper-melters".

In my own, ever so humble, personal opinion, there's little point in anything more than observation until the end of the melt season, then and only then can a post mortem be held as to how much ice melted, compared to when, and why.

[acbrixton]

Last years record losses where put down to a conflagration of differing phenomena that all aided in the record loss.

This year the Arctic has shown more 'average' conditions and yet still we are already looking to be the second lowest amount of sea ice in the Arctic come seasons end.

Clearly then that it is AGW, as temps are normal there's more melt? Must be getting warmer :lol:

BFTP

BFTP, is it not plausible that at least part of the explanation for what may well be the second lowest Arctic sea ice minimum is that there was a smaller than average proportion of 'tougher' multi-year ice (and therefore a higher proportion of 'weaker' single year ice) at the start of the 2008 melt season following the record melt of 2007?

In such circumstances one might expect significantly greater melting despite 'average' conditions.

That hypothesis was first set out here about 12 months ago and I cannot recall any attempts to refute it.

BTW: I think you mean 'concatenation' as opposed to 'conflagration'!

regards

ACB

[The Eagle]

As last winter had more ice than the winter before

Yes and if the melt is lower then last year this winter will up that again as seems likely.

[Roger J Smith]

I think it's fair to say that I represent over half the man-ice days of the combined NW forum, and one thing I learned was, it always melts fastest at the end.

[Android]

I reckon 'combination' is the right word.

The (quite intuitive I think) premise is that multi-year ice tends to be thicker on average than single-year ice, therefore less multi-year ice equals thinner ice overall and so a smaller minimum extent is more likely.

Questions that would be very useful to have answers for. At maximum extent:

What is the average thickness of single year ice?

What is the average thickness of two year old ice? three? four?

And importantly what is the variance of all these? At the point of maximum extent you might find two-year old ice at the edge of last year's min extent is only 2% thinner than neighboring one-year old ice.

Maybe ice thickness has a more significant relationship with "distance from last year's min extent boundary" than with it's age. I dunno, this might be completely wrong. I could spend a lot of time hunting all this down, but experts who have done this already have concluded the single-year, multi-year difference is significant so I will stick with that.

Edited August 18, 2008 by Android

[The Eagle]

I think it's fair to say that I represent over half the man-ice days of the combined NW forum, and one thing I learned was, it always melts fastest at the end.

Aye but it wont be lower then last year - thats pretty much certain at this stage. Even after last years big melt the Ice extent was well up on the previous Winter at peak.

[acbrixton]

I reckon 'combination' is the right word.

I think you may be right!

regards

ACB

[LadyPakal]

Some here may find this link interesting (Iposted it in the other thread) - it is a blog written by the crew of a boat sailing through the NW passage. There is new ice forming in places apparently and they are find the maps (from the Canadian Ice Service) they are using pretty accurate.

http://awberrimilla.blogspot.com/2008/08/l...-map-again.html

Note that the bog format cuts the maps off to the right - save to desktop to see the whole thing.

[Gray-Wolf]

The 'multiyear ice' , as I understand things, can be either berg/shelf chunk or ice that has over weathered/grown over many winters. Ice ,we know is 90% submerged so a 3m thick chunk impacts the waters it is submerged in to a greater depth than 90cm, single year ice.

This year's winter ice had a slow start with many 'false starts' in areas as thin ice was smashed by sea swells. I think we can expect more of the same this year.

Another point to reflect upon is the cold end to last winter .Even with this colder than average 6 weeks the melt season still started 6 weeks early and we still find ourselves with the dwindling pack today.

The ice formation/weather link seems to now be unravelling somewhat now with the 'ice type' being the major driver in ice loss with the less durable 'single year ice' melting out to reveal the 'dark waters' below by mid melt season (or the 'dark ice' as we saw this year).

The flip flop from 90% reflection to 80% absorption is the biggest 'swap around' in the energy the north receives.

EDIT: If melting continues at the current rate for the next 3 weeks (no slowdown) then we will excede last years melt min. As RJS pointed out, things melt faster at the end! With small chunks of ice now surrounded by lots of warm (relative) waters you can see why.

Edited August 18, 2008 by Gray-Wolf

[Roger J Smith]

Sorry, my remarks were (a) the usual RJS lame attempt at humour, but also ( :lol: a much more long-term assessment than this season.

My experience with ice melt on Canadian lakes is that the areal extent changes slower than the ice thickness, then you get into a situation where you're losing five or ten per cent a day, it becomes driven more by wind than temperature, and then, boom, one day (or quite often one night) it is gone with a loud noise sometimes accompanying its disappearance.

In the case of the Arctic Ocean, I envisage that if the natural warming trend continues for some number of years (probably 10 to 20), there will come a season where this all happens on a much larger scale. The final end of the ice pack in that season will quite possibly be a hotly debated topic until days before it suddenly breaks up and vanishes.

But that doesn't mean that it will stay that way for any predictable length of time, the ice will be bound to return to some regions seasonally, and then one year will come when it doesn't all melt, and the cycle will be over for the time being.

If this is all that happens (i.e., no big meltdown in Greenland or Ellesmere Island), it may have a more unpredictable effect on climate than the IPCC is saying. It could start a process towards hemispheric cooling. There is so little information available of a conclusive nature on historic climates, this could easily have happened for 5-100 years in such episodes as the Medieval Warm Period and even the end of the relatively warm 16th century before the Little Ice Age set in full blast.

We simply don't know as much as we need to know, to be sure of anything, and then there is this wild card of human activity.

But as a scientific question without political overtones, if the ice does melt for whatever reason, it will go quickly at the mid-way point of some future summer, it won't be a gentle increase over many years. There are critical values of thickness and extent, interacting with wind and temperature advection, that all tend to mutually reinforce towards the warm end of the spectrum in a given situation, and the ice goes boom. Literally. (I heard an ice boom in May, 1975 when thick ice from an unusually cold April finally melted in a heat wave situation on a large lake north of Toronto, and it sounded like a series of explosions from a munitions factory blowing up, but at some distance, it wasn't deafening, and I was only a few hundred feet from the shore. On the final day of this melt, the ice had "candled" and was lying in crumpled sheets like the remains of some cheap warehouse after a tornado has hit -- it was dark too, not grey-white like it had been before, but dark blue and black streaks).

[BLAST FROM THE PAST]

BFTP, is it not plausible that at least part of the explanation for what may well be the second lowest Arctic sea ice minimum is that there was a smaller than average proportion of 'tougher' multi-year ice (and therefore a higher proportion of 'weaker' single year ice) at the start of the 2008 melt season following the record melt of 2007?

In such circumstances one might expect significantly greater melting despite 'average' conditions.

That hypothesis was first set out here about 12 months ago and I cannot recall any attempts to refute it.

BTW: I think you mean 'concatenation' as opposed to 'conflagration'!

regards

ACB

I was being facitious and conflagaration wasn't my quote it was what I was responding to... :lol:

Roger, although Europe missed that real cold there was very high and very early snowfalls for the Alps with incredibly early open season.

BFTP

Edited August 18, 2008 by BLAST FROM THE PAST

[doctormog]

As RJS pointed out, things melt faster at the end! With small chunks of ice now surrounded by lots of warm (relative) waters you can see why.

I think you'll find that, as with any sine type cycle things slow down towards the end befor an upturn

cf. http://nsidc.org/data/seaice_index/images/..._timeseries.png

All things being equal we should be starting to see that slow down begin soon as the polar day shortens. the next couple of weeks will show whether or not that happens - not someone's opinion of what might happen, but the actual melt rate in coming weeks.

Show me a year where the melt rate i.e. decline in ice extent accelerates from mid-August to mid-September in the Arctic when compared with say mid-summer. The period of fastest ice melt is surely June/July into early August before a slow down and reversal at some stage in September or even October but certainly no sign of things melting faster at the end as temperatures decrease.

I'll take that back if someone can show me a graph stating otherwise. Please.

[Iceberg]

I'd agree with that doctormog. Things tend to slow down in August and also become more variable, with occasionally large declines and also some increases if conditions are right. As you go into September the balance equals out with only a slight decline or upturn depending on the conditions and the upturn in October starts proper.

I've got a feeling that the upturn will happen a week or two before last year's, due mainly to the colder SST's and the cooler synoptics. There was a lot of latent heat last year that had to removed from the system before the freezing could start and this is not the case this year.

[trevw]

I'd agree with that doctormog. Things tend to slow down in August and also become more variable, with occasionally large declines and also some increases if conditions are right. As you go into September the balance equals out with only a slight decline or upturn depending on the conditions and the upturn in October starts proper.

I've got a feeling that the upturn will happen a week or two before last year's, due mainly to the colder SST's and the cooler synoptics. There was a lot of latent heat last year that had to removed from the system before the freezing could start and this is not the case this year.

on the other hand, by this time last year there was little to no thin first year ice left I would have thought? Therefore large amounts of melting were required to continue to reduce areas/extents.. Whereas this year there is still a bit of the thin stuff to go so even conditions condusive to mild levels of melting can have an effect on area/extent until later in the season?

[Cycles]

From what I understand about ice melt in the Antarctic is that new ice melts quicker than old ice. This could explain why even though temperatures were more normal in the Arctic this summer, the big warmup duirng the past couple weeks was able to melt a lot of the new ice.

I also understand that deep water currents in the Antarctic is allowing ice to continue melting in areas with a warmer current, and ice accumulate where the current has cooled. It takes deep currents longer to cool than air temperatures, probably a few years lag time in some cases. So perhaps some of the Arctic melt is due to some left over warm currents melting new ice. Overall temperatures have been much cooler across all of Canada this summer, with the exception of the past week or 2.

[trevw]

Doesn't new ice melt quicker in part because it is more saline? Older ice somehow purges itself of salt slowly becoming fresher and thus having a higher melting temp? Or is that wrong..

[doctormog]

on the other hand, by this time last year there was little to no thin first year ice left I would have thought? Therefore large amounts of melting were required to continue to reduce areas/extents.. Whereas this year there is still a bit of the thin stuff to go so even conditions condusive to mild levels of melting can have an effect on area/extent until later in the season?

Have you got a link to back this up (for age and ice thickness) for this year and last) or is it supposition?

[trevw]

Have you got a link to back this up (for age and ice thickness) for this year and last) or is it supposition?

I think supposition (as in assumption) is possibly a bit harsh I would say more of a logical derivation from various sources..which could of course be based on incorrect assumptions (I did say 'I would have thought' in there somewhere to indicate it was speculative..)

Thought processes being:

1) Last year the remaining area was far smaller than ever before.. this would suggest that a lot of the remaining ice was there probably at least the previous year - this ignores ice pack mobility which is where this might fall on its face.

2) This winter we had a large refreeze, everything above last years minimum area (or outside the area of minimum extent) is obviously single year ice.

3) This year we are behind last years melt and so in all likelyhood have not melted all of the single year ice.

simplistic I know and I would not suggest any figures be calculated on this basis due to differences in melt patterns, movement of the ice etc. but surely the basic premise holds?

What do you reckon?

Trev