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How does CO2 explain what Bill pointed out?Could something else be involved - natural cycles perhaps
Originally Posted by: four
What a bizarre post Four? Bill's post demonstrates exactly my point. Where in that table do you see CO2 levels anywhere near the current level? This is most emphatically abnormal.
Weird....
Mabey I should have been clearer Gandalf.I did'nt mean remaining at the peak.The melt curve is rather flat in comparison to recent years don't you think.I would show a number of graphs here but I am having some problems with pasting at the moment.could be my recent IE9 Download.
Originally Posted by: AIMSIR
Hi.
The decline since the peak is not far out of line with other years, slightly less to date but not that significant. Because the date of peak ice extent varies by about 3 weeks it is difficult to be definitive without more work but we have lost approaching 500k since the peak this year and the normal rate would be nearer 600k.
It may have something to do with the thinning ice breaking up - as ice extent is measuring areas with at least 15% coverage you can see how the extent might rise if a large piece fragmented.
Originally Posted by: Gandalf The White
I'll try to post some graphs.
I really think this year is a tad unusual as the curve seems to be flattened.
Can you not see this?.
Hi AIMSIR,No, I haven't missed the point; I thought I had answered it? The rate of decline isn't very much different to normal - just slightly slower.
Mabey I was reading too much into it.
Like a dog with a bone, comes to mind.
Thanks for your explainations.I'll take them on board.
http://www.arctic.noaa.gov/gallery_np.html
Pole cam up and running.
Originally Posted by: Gray-Wolf
Cheers.
It's taken a lot longer to drop below 13 million (than I thought) but we are now about to enter the melt season properly. The Russian side is looking like the area to start showing major drops but the ice is not in good shape across the basin really. Some areas are already looking weak and ready to beak apart?
As for the plug across Nares? well what can I say! it's been doing a fine job since the front fell away leaving a concave ice front but it must fail soon esp with the temps warming up now across Canada/Greenland?
It's taken a lot longer to drop below 13 million (than I thought)
Yes, the melt seaon so far has been slower than I was expecting too. I suspect this might have been due to unfavourable synoptics. We had very positive AO in March and much of this month - a pattern that brought persistent warmth to the UK. The pattern has now changed so I suspect the ice melt will be greater in the coming weeks.
Our first 100k+ melt day from IJIS yesterday (pre adj. 112k). now we have AO-ve again and temps rising on the canadian /Greenland side of the basin I'd expect more to follow?. Nares 'ice bridge' also looks to be failing over the next few days(?) with plenty of melt to it's rear? The measured increases in fresh water flow in the Canadian Archipelago and northern sector of Nares may mean that the bridge comprises of a lot more 'fresh water#' making it stronger than F.Y. sea ice and it's cargo of salt?
We are now 3rd in the series on the IJIS plots and I can see us dropping to lowest by mid-May (going by the state of the Siberian side of the Basin and the rear of Bering). With the temps now rising across the rest of the basin I cannot envisage us rising above lowest in the series thereafter.
I can see us dropping to lowest by mid-May
Yes, I would think that is likely looking at this chart. We have now caught up with 2007, but 2007 had a very steep decline from mid-June to early August so it will be interesting to see whether we stay below 2007.
www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
Hi John!
It depends whether that 'steep decline' was merely a product of weather favourable to melt or whether it reflected ice age/thickness? They say this years ice is slightly 'older' than last years but none is over 5 years old (when most of the salt has gone from the ice) and most all of the ice is sub 2.5m thick.
My concern is that we saw what a 'skimpy pack' acts like under average melt conditions. If we see this again this year without any major help from weather (ie in-situ melt under average conditions) then I wonder about the late July /Aug melt. We know that ,last year, we had a 'slow down' in melt rates but we also saw the last of the Beaufort sea paleocryistic melt out over this period. Weaker ice would have secumbed quicker leading to higher melt (more open water warming more ice etc) and this year we only have 'weaker ice'.
Nares ice bridge seem to be crumbling slowly on the southernmost contact with Baffin also. Yesterdays/this mornings images show less of a 'scallop' and more of a 'V' shape? Odd that, I truely expected a catastrophic collapse (like we saw last year in the western end of the NW Passage?). Once this impasse is cleared ice losses will pick up again even with cool weather.
Originally Posted by: John S2
I have a feeling as long as it stays cold(might not) around Hudson the drop off could be a bit slower this year.
Last year it(Hudson) melted like an icecream on a hot sunday and we saw a rapid drop off only to slow down when things got to the serious ice.
Still, it was a big blow for Beaufort when it did, and a lot of damage done.
Some interesting points on the Nares bridge, Gray Wolf btw.
The extent figure still looks OK but the ice looks very thin over large areas.
I'd agree on both points Ulric!
I'm pleasantly surprised by the slow rate of loss so far this year but , and it's a big 'but' , with such a low start point and ice already looking 'stretched' and patchy I have concerns about both high and late summer.
We should have the U.S. 'icebridge data soon enough but the little snippets we've had from them suggest that the Beaufort ice is down in thickness (again) and so will take less to melt it all out (again).
And empty Beaufort provides room for the remainder of the Paleocrystic (currently stuck to the north of the Canadian Archipelago) to be pushed out into open ocean by the Beaufort Gyre and we saw what became of the 'babies arm' of ice that did that last year!
With poor ice formation over on the Russian side of the basin (unlike last years thick ice there) we can expect a rapid melt out there also.
All we can hold out for are those touting low solar /Nino/PDO-ve to come up trumps and slow the pace of ice loss over the summer months?
Hi Grey wolf.Have you any ideas on the Fram Strait export,this year.
Nares still looks to be holding.Albeit barely.
The ice is thin in places as Ulric says.
How will it get out to melt this year do you think?.Mabey the Canadian side.But it's remaining quite cold there this year.
I'm pleasantly surprised by the slow rate of loss so far this year
Yes I am surprised too. I did notice that in the AO index table published by NOAA the April figure was by far the most positive for April in a record going back to 1950. This will surely have slowed the melt compared to what we would have seen with average synoptics. I would be interested if anyone has any alternative explanation/information for the slower than expected rate of melt.
Also ,it has been particularilly cold on the Canadian side.
There are many explainations for this.To pick one could be difficult.
I get the distinct feeling that we will all continue to be surprised by this years 'melt season'? Last year saw the Canadian Archipelago 'scraped clean' of all it's channel/land fast ice and so this year it looks like it could clear out the main channels by mid July(ish). This raises the prospect of another 'exit' from the Arctic basin coming into play for the first time (at least for this 'melt').
The new exit would be over 4 times the dimension of Nares (still ice bridged) but making the old 'ice retaining' weather setups turn into 'ice export' synoptics. Not a good turn of events.
Last year we saw the Beaufort Gyre export multiyear ice into the rear of Bering (where it all melted) so we have seen the 'old Arctic' turned onto it's head with the old 'positive for ice retention' synoptics now favouring ice loss. With the NW Passage seep channel now likely to become an ice exit into Baffin any ice pushed up against the Canadian Archipelago coasts will not over-ride/compress into the thick multiyear but flow into the N/S channels of the Archipelago into the deep channel and out of the Basin.
As such I'm watching both the 'ice bridge' across Nares and the NW Passage deep channel (now near 2/3 broken ice already!) to see how fast they both clear.
C.T. today also shows some very thin and patchy ice near the pole so maybe this year we will see an ice free geographical pole? Keep watching the North pole cam come July!!!
Originally Posted by: Solar Cycles
I think this is a hard one to nail.
The melt is not going as some expected this year.
Still, it should be an interesting summer.
Might get busy here over the next few weeks.It's a funny old place up there.
I agree, I think its complicated. The extent line is still meandering about in the midst of previous values and there is less year on year variability during May anyway. I am a little concerned about how thin the ice is towards the Pole though.
Originally Posted by: Ulric
Massive amounts, volume wise where shifted early last year, towards the Beaufort, chuckchi area where it melted.Unfortuneately.
There is an increase in volume overall this year and so far, some retention. hopefully, this will continue.
We are on thin ice though, Cycles .excuse the pun.
Hi Ulric, I think the graph can be somewhat misleading. The 1979-2000 mean for ice extent for this stage in the melt season is around 13.2 million sq km: the current value is around 11.6 million.
We have yet to see the first 100k loss in a day this year. Every year since 2004 has seen several such days by early June. It will be interesting to see how the next couple of weeks shapes up - if we get any sort of acceleration we will be close to new lows this decade.