This is a continuation of the previous (and now unwieldy) post on the current Arctic situation. We’ll have a proper round up in a few weeks.
kfr wrote in 443:
Re the telegraph, there does certainly seem to be an agenda being pushed there (from the guardian)
I went ahead and looked up the link:
Here is a cautionary tale for anyone working in research. “Captain Cook and Lord Nelson seem unlikely figureheads in the fight against climate change alarmists,” said the Sun. “Lord Nelson and Captain Cook’s ship logs question climate change theories,” announced the Telegraph….
Don’t let the facts spoil a good story
by Ben Goldacre
The Guardian, Saturday September 13 2008
Here is a cautionary tale for anyone working in research. “Captain Cook and Lord Nelson seem unlikely figureheads in the fight against climate change alarmists,” said the Sun. “Lord Nelson and Captain Cook’s ship logs question climate change theories,” announced the Telegraph….
Don’t let the facts spoil a good story
by Ben Goldacre
The Guardian, Saturday September 13 2008
#448 “From the negative snow depth I’d guess that the ice was less than 50 cm thick last year and the ice temperature plot suggests about 20 cm now.”
I strongly disagree with your analysis, but since we’re all guessing it’s rather pointless to go into too much detail.
But factors I would consider:
- The buoy is on multiyear ice
- The stated initial ice thickness is 290 cm (corresponds to green line exactly, not red minus green)
- The buoy has drifted towards the North Pole
- Compare buoy data to corresponding IceSAT thickness estimates
- Note shorter peak in summer temperatures
- Note lack of downward red curve in thickness data from other buoys
- Flattening out of green line starts in late Aug/Sep both years
- Possible effects of surface melt puddles
- Even NSIDC map shows thickness as 1.35m on 20th Aug.
Even though we’re all guessing, I would be inclined to stick my neck out and say “20cm – no chance”. If nothing else, consider where the buoy is in the Arctic
and consider where Lewis Pugh had to turn back due to first year ice “only” 1m thick, or where the Russians recently set up their new station on a floe that was up to 2.8m thick. Do you really think the ice in what is normally the Arctic’s thickest ice area is currently 1/5th to 1/15th the thickness of the floes on the periphery?
Perhaps it would be better if I simply let some people posting on here believe the Arctic has already passed a tipping point in the way you seem to be assuming. That way, you’re happy, and I’m saved a lot of effort. Goodbye, and good luck.
Chris; Either you know the ice or not? I have my doubts about your motives. But I will explain to the wider audience, as this kind of Journalism has gone long enough without immediate responses. I am still laughing at how poorly crafted and ignorant this piece of contrarianism reads…
The image given by the Telegraph is:
1- It was warmer in 1896
2- So much warmer that Nansen paddled his Kayak from Spitzbergen to 82 degrees North
3- Not unlike that British chap who barely managed 80.5 degrees in much cooler conditions in so called Global Warming times. Direction of paddling had huge meaning here (BTW Pugh was brave but not well advised)
Isn’t that lying? This article is not OTT , it gives a faulse image, written on purpose to fit an agenda, made amply clear when reading below. The agenda is : destroy AGW theory or delay its acceptance by the wider public, by undermining the most senior scientists supporting it. They failed, in this case, by showing outright Polar ignorance.
82 degrees North is close to the average summer ice extent limit around Spitzbergen. All that ice faced recently by the modern kayaker further South is loose pack ice quickly flowing from a very fluid disintegrating ice cap. Nansen sailing Southwards at 82 N from a failed attempt to sledge to the Pole is normal for a consolidated “average” year. http://www.fram.nl/faq/name/map_fram_voyage.jpg Again an omission, to say the least. The Fram itself would not have been beset at the same location North of Siberia, and not stuck for 2 to 3 years on pack ice given this years and last years wide open water events, besides Nansen and crew would have jumped on the occasion to make history and circle the Pole in less than no time , doing the complete NE and NW passage in less than one summer season. But that was not the case in 1893-6, the Fram was stuck in formidable ice, as it was then, therefore the Telegraph transposed another faulse image by omitting the true nature of the Polar ice cap then, by suggesting that there was more water at 82 N…..
Defending this article, then calling it OTT is meaningless! The Telegraph should apologize, otherwise they will be trapped by their own pack of mean ice, beset in their own fabrications and lies.
#450 Terry, Full moon effects are always fascinating to watch.
A few additions, the Fram was stuck in the ice sep 22 1893 (not 1894 as on a website I used) , near the New Siberian Islands , completely ice free now. it drifted for 35 months ending up amongst 10 meter ice ( non existent or extinct today). Much further North Its drift track followed closely to the ice edge of now in 2008, there would have been no drift track in 2007. I think it completely unforgivable to use the efforts of man trying to expose Global Warming, risking his life for the effort, and twist it around by claiming no such thing. Journalism has hit an all time low with respect to this subject….
> Goodbye, and good luck.
He’ll be back under a new name from the same old IP address, I bet.
Comparison of the Bremen map to MODIS Rapid Response System photo
Strange overnight ice at Hudson bay
I’m not sure about Chris’ motives either, but it’s always good to have someone with a different perspective to further a discussion (and Chris’ asides show he’s not 100% denialist or anything). Myself, I’m a 100% alarmist layman and I enjoy reading all comments here. If it weren’t for Chris this comment thread would probably have died off silently, and where would I go then? There haven’t been any new comments on Tamino’s blog for a week now (on the ‘more less ice’-thread I mean) and the comments on WattsUpWithThat or ClimateAudit make one very, very tired (because of their one-sidedness and 95% ignorance). I come and read here almost every day and find the comments even more interesting than the articles themselves.
I don’t have the knowledge or intelligence to comprehend the science so I have to go on other people’s opinions. The content of their texts and their writing styles reveal a lot about their motives and level of knowledge. This is what I go on and it helps me decide about what is more probable.
I for one hope Chris is right and that the North Pole Ice hasn’t passed a tipping point, though it perhaps might help in making people more aware of the gravity of the situation and the causes behind it. I long to be a ‘contrarian’ or ‘denialist’, but AGW as a hoax or conspiracy just doesn’t cut it for me. I would sooner think AGW is real and part of a greater conspiracy.
#453 Wayne: “I have my doubts about your motives.”
I wasn’t going to say any more on this thread. However, I will say this, you don’t know how wrong you are. I am an ordinary guy, a citizen of the world, sitting at my computer with every right to take part in a balanced debate. I am very interested in meteorology and climatology, so much so that I am doing a Masters in the subject. I find the consensus theory on AGW quite convincing, and as such I am concerned about what may be happening to the earth’s climate, and in particular in the Arctic in the last couple of years.
Believe I’ve got some kind of bad motives if you like, and insinuate this to the “wider audience” as you have already done. You’re absolutely wrong – I tell you categorically, there is nothing wrong with my motives! I find your insinuation offensive (as should be obvious).
If you really want to convince the “wider audience” of your views, I suggest you think about the best way to achieve this. It seems to me that it’s the kind of attitude you’ve been taking which drives people to skepticism who would otherwise pay more attention to the warnings of climate scientists re: AGW.
Your portrayal of the image given by the Telegraph re: Pugh/Nansen is false. The journalist is pointing out that Pugh’s expedition provided little evidence of “unprecedented global warming” – this is correct. You’re insulting the readers of the Telegraph to suggest they would necessarily read into a comparison of ice in one specific part of the Arctic that the world (or indeed the Arctic as a whole) was warmer in the 1890s. As for the article in general, yes it is full of spin (which I don’t approve of). But not lies.
Re: the ice to the north of Spitzbergen, consider the following extract from Nansen’s account from earlier the same summer.
… Friday, May 24th … While we were having breakfast today I went out and took — altitude, which, to our delight, made us 82° 52′ N …
Sunday, May 26th … I reckon that we did 20 miles … yesterday, and should thus be now in latitude 82° 40′ N … I am in a continual state of — at the ice we are now travelling over. It is flat and good, with only smallish pieces of broken-up ice lying about, and a
large mound or small ridge here and there, but all of it
is ice which can hardly be winter-old, or at any rate has
been formed since last summer. It is quite a rarity to
come across a small tract of older ice, or even a single
old floe which has lain the summer through so rare, in
fact, that at our last camping-place it was impossible to
find any ice which had been exposed to the summer sun,
and consequently freed from salt. We were obliged to
be content with snow for our drinking-water. Certain
it is that where these great expanses of flat ice come
from there was open water last summer or autumn, and
that of no little extent, as we have passed over many
miles of this compact ice the whole day yesterday and
a good part of the previous day, besides which there
were formerly a considerable number of such tracts in
between older, summer-old ice …
Friday, May 31st … The ice we are now travelling over is almost entirely new ice with occasional older floes in between. It continues to grow thinner, here it is for the greater part not more than 3 feet in thickness, and the floes are as flat as when they were frozen … Took a — altitude today, and we should be in 82° 21′ N …
Sunday, June 22nd … The lane which stopped us yesterday did not close, but opened wider until there was a big sea to the west of us, and we were living on a floe in the midst of it without a passage across anywhere. So, at last, what we
have so often been threatened with has come to pass:
we must set to work and make our kayaks seaworthy…
Keeping a sense of perspective (as I’m trying to do) does NOT imply bad motives, nor detract from the AGW case – if anything, it can help strengthen it.
(And by the way I don’t think the Telegraph article is in perspective, it seems to be an OTT polemic against “alarmism”. But not lies.)
Of course, the Booker article isn’t all that Telegraph readers get to read about climate change – see e.g. the following article from yesterday (the day after the Booker article)
“Polar bears and other rare species are in danger of dying out, scientists fear, as latest figures show the Artic sea ice is at record lows”
“Scientists from the World Wildlife Fund, who are recording the ice cover over the North Pole, said less ice is predicted in the Arctic this year than in any other.”
“The area of ice that is at least five years old has dramatically fallen by more than half since 1985. It comes as the Northwest Passage, over the top of North America and the Northeast Passage, in Russia, are both free of ice for the first time.”
“The worrying trend in Arctic sea ice loss provides the clearest evidence yet for the need to decisively tackle climate change now, both at a national and a global level.”
Wayne Davidson: “They failed, in this case, by showing outright Polar ignorance.”
Oh, would that that were so. The goal is to give comfort to likeminded individual in the denialist community. Since such individuals will never read anything published in the Guardian, they will cleave to the Telegraph as a bastion against “Mainstream Media” or “MSM”. Never before have people had such free access to information. Yet, they persist in (to paraphrase Andrew Lang) use information as a drunkard uses a lamp post: more for support than illumination.
Are you serious? Are there such things? The ice is stretching out in wide gaps.
btw, it is “Tenney” not “Terry.”
Sorry Tenney! Yes there is such a thing, was expecting a rotation of the entire ice pack as on about Sept 1, but winds may play havoc with the ice just as much. Will need to wait a bit to see what happened. Lunar spring tides play a major role on creating leads some 20 to 40 miles wide (if combined with other physical ice vectors).
Chris, You are delightfully hopeless, enjoy believing the Telegraph! Neven, we can do better than defend a paper which writes garbage.
Ray, I dont think people should cling to falsehoods, reality hold nothing on science fiction. Current ice conditions are so far the beaten track it may be considered as fiction, but describing it otherwise as “normal” or worse “cooler” is a perspective off the cuckoo train.
Thank you, Wayne, I didn’t know that.
The discussion here has been worrying the issue of ice minimums, but the Hansen papers on sea level rise have focused on changes in spring albedo. At least that’s the way it looks to me. Has there been a large change in ice extent in the spring?
The NSIDC ice thickness data don’t show 1.35 m for buoy #07413 (2006C). That buoy has been at 84.85° N, 134° W on 2008-08-20, about the position where the NSIDC map has a measurement of 0.43 m (and 1.83 m at the beginning of the melt season). That would match the approximate ice thickness that I can derive from the ice temperature plots of buoy #07413. 1.83 m also match the ICESat thickness estimates for Feb-Mar 2008.
“Ice temperature” has been at +3 °C down to “depths” of ~ 70 cm on some days during summer, that doesn’t look like ice (nor melt ponds).
The ice floe hasn’t been real multi-year ice a few months ago. It barely survived 2007 and most of its thickness has been new ice that formed last winter. I don’t expect such ice to behave like multi-year ice (but I don’t know; what is left now might be real multi-year ice).
In 2007, the floe has been quite south in the Beaufort Sea (I posted animations of its track in the first part of this thread: Full lifetime, weekly (2.3 MB), 2007 melting season, daily (4.1 MB)). Of course, the temperatures tend to be higher there than in its current location. But last year the amount of ice melted was much more than this year, and most of it was real multi-year ice. So the data look very consistent to me.
The current location of the floe isn’t the area of the Arctic’s thickest ice (that’s more close to the Canadian Archipelago and Greenland). It’s an area where ice typically comes from the Beaufort or Chukchi Sea, where some ice may have melted in the season before, just like it happend with this floe.
Note that I do not claim that this ice floe is typical for a larger region. Even the buoy data isn’t necessarily typical for the floe it is on. The latest NIC ice analysis shows 90+% thick (> 120 cm) first-year ice there (same as the area around the North Pole during the last months) and 30% multi-year (> 200 cm) / 60% thick first-year ice directly west of it. NP-36 is near the border of 30% multi-year / 60% thick first-year ice and 40% multi-year / 40% thick first-year ice (a region with 90+% thick first-year ice and traces of multi-year ice is not far to the south-east).
#456 Hank Roberts “He’ll be back under a new name from the same old IP address, I bet.”
#463 Wayne “Chris, You are delightfully hopeless”
#455 Wayne “A few additions, the Fram was stuck in the ice sep 22 1893 (not 1894 as on a website I used) , near the New Siberian Islands , completely ice free now. it drifted for 35 months ending up amongst 10 meter ice ( non existent or extinct today).”
Nansen: “We were frozen in north of Kotelnoi at about 78° 43′ north latitude, September 22, 1893.”
i.e. current ice edge at that location is ~78N
APPENDIX REPORT OF CAPTAIN OTTO SVERDRUP ON THE DRIFTING OF THE “FRAM” FROM MARCH 14, 1895 CHAPTER I March 15 to June 22, 1895
At the time when the sledge expedition started the Fram lay in 84° north latitude and 102° east longitude. The situation was briefly as follows : The vessel was ice-bound in about 25 feet of ice, with a slight list to starboard. She had thus a layer of ice, several feet in thickness, underneath her keel. Piled high against the vessel’s side, to port, along her entire length, there extended from S.S.E. to N.N.W. a pressure-ridge reaching up to about the height of the rail on the half-deck aft and slanting slightly eastward from the ship.
by June 8th we again had an easterly wind with a good drift to the west, so that on the 22d we were at 84° 31.7′ north latitude and 80° 58′ east longitude
In the evening of August 8th our floe cracked on the port … I feared that the small floe in which we were now embedded might drift off down the channel … half an hour later the Frain was already drifting down through the channel.
Once or twice it seemed as though the Frant would be afloat again before the winter finally chained her in its icy fetters. On October 25th, for instance, it slackened so much in the lane nearest us that the ship lay free from the stern right to the fore- chains ; but soon the ice packed together again, so that she was once more frozen quite fast.
On April 13th Scott-Hansen and I took an observation … the latitude was 84° 11.5′
So when the sledge expedition had started i.e. mid-March 1895, the Fram was “ice-bound in about 25 feet of ice”. This is the closest I can find to the “10 meter ice” Wayne refers to. It is somewhat ambiguous what the “25 feet” refers to i.e. was the ice floe (as it adjoined each side of the ship) 25 feet from top surface to bottom surface, or does the “25 feet” include the “pressure-ridge” that was “piled high against the vessel’s side” ?
Let’s assume that the ice floe itself really was a full 25 feet thick. That’s 7.6 metres.
Well, consider the following buoy installed in a second-year ridge in the Beaufort Sea in 1997
Note the initial ice thickness of 8 metres. In other words, it appears that it’s only 11 years since a second-year ridge was able to reach a greater thickness than the ice the Fram was stuck in, at a lower latitude than the Fram.
It was fascinating to research, but it took a big chunk out of my time – please stop saying things which keep dragging me back :)
Ray Ladbury’s comment:
“Never before have people had such free access to information. Yet, they persist in (to paraphrase Andrew Lang) us[ing] information as a drunkard uses a lamp post: more for support than illumination.”
A delightful and apt turn of phrase. (Though the phenomenon itself is not so delightful.)
The NSIDC has tentatively declared a sea ice extent minima for the year of 4.52 million square kilometers set on September 12, 2008.
Click the link above for their analysis.
Captcha fortune cookie: and entirely
And I have concerns about your motives. I have concerns about your ability and about your intelligence.
However, I do not post messages about those concerns.
Until you started it.
Oracle Knows: captcha: relations rifle
The NSIDC just declared a preliminary minimun of 4.52 million sq. km. on Sep 12, 2008.
Final results will be released in early October.
So we had two totally different years weather wise, and we got virtually the same ice lost.
#470, LG, but we have not heard any word on volume. Clarence was kind enough to give us a rough estimate for this year. Would really appreciate to hear about volume numbers, get use to them.
You are totally right about the weather, the ice is leaving a footprint from the season just past, of this years weather dominated by Low pressures, at least or the most initial period of the melt season.
Many apologies I took the wrong buoy on this occasion re: NSIDC map. And thus the tone of my post was misplaced, and I picked the wrong occasion to make my comment about “some people posting on here” (which wasn’t really aimed at you by the way).
Having said all that, I don’t agree with the inferences you make from the “Ice temperature” data, but it’s quite hard to explain why. Perhaps the best thing I can do is take the example of buoy 2008F, since this was installed on 8th Aug 08 and has “Ice temperature” data available for 6 days afterwards i.e. 14th Aug 08 – when we know from looking at the snow-ice thickness plot and air temperatures that there couldn’t have been more than ~10cm melt, indeed if anything surface snow level increased (air temperatures were consistently below zero, mostly around -1C during this period).
Yet buoy 2008F “Ice temperature” data for 14th Aug show temperatures of up to +1C down to ~60cm depth.
Compare buoy 2006C, which you are claiming to be currently in only ~20cm thick ice. The maximum its “Ice temperature” reached was comparable i.e. +1C, down to a couple dozen cms lower. Now, of course, it is showing about -11C down to ~90cm, then a jump to a consistent -2C from ~110cm (just like other buoys which we know to be in relatively thick ice).
To me this all suggests that there is not much that can be inferred from the 2006C buoy’s “Ice temperature” data, especially since we know that the surface level of the ice had probably already dropped significantly following the summer of 2007. Thus I would still take its snow-ice thickness plot at face value (i.e. ice thickness of over 1m plausible)
Of course, given the mistake I made, I take your other points, including:
“The current location of the floe isn’t the area of the Arctic’s thickest ice…”
“Note that I do not claim that this ice floe is typical for a larger region…”
The fact that end of season area/extent are similar to last year leaves out the thought that – with the documented thinning – the total volume/mass of ice in the artic ocean is well down from last year. How does that work out – pixel by pixel?
Thus is it likely that the energy used this year to reach the same extent was less than last year, which means (the global energy input being roughly the same 2007-2008) that there is more energy ‘left over’ to heat water, air and ice elsewhere?
The fewer the sinks the faster the warming? The spiral gets steeper?
#474 Nigel, Unless volume accounting is done, there are some questions not giving easy answers.
If volume can’t be measured accurately, then I suggest looking at atmospheric Density Weighted Temperatures of the Polar region. My local readings are quite formal, there was no temperature cooling for the troposphere as a whole, therefore quite similar ice shrinkage results despite much greater clouds and unfavorable winds. All it takes is to crunch the numbers.
#464 Tenney, Your curiosity deserves this observation:
Load the last 15 days, look at the coast off Ellesmere, water shows when the moon was roughly full.
THe Buoy just North of Ellesmere is moving at an incredible pace as well.
#471, NSIDC declaration is surely tentative all right, but the ice is still disappearing in some parts.
load last 5 days
as an example; watch that once , now small ice disappear between Wardle and New Siberian Islands on Russian side.
NSIDC Arctic sea ice extent has dropped again by 42’000 km² (unsmoothed daily values). The 5-day running mean (F15 data) used by NSIDC is now at 4.520 million km², compared to the 4.524 million km² 2 days ago at the tentatively declared minimum.
Tomorrow (today’s data) it is likely to rise again, because the lowest single day value (4.501 million km² on 2008-09-12) leaves the running mean (unsmoothed data available here).
I don’t think that the upper ice edge has ever been at zero for buoy 2008F either. Note that the axis is labeled “relative depth”. But the bottom ice edge is hard to see there. You need a more pronounced temperature gradient to see it in the plot and watch its behavior for a few days to be sure.
Tenney Naumer (and Wayne),
I disagree with Wayne’s assertion that the cracking you have observed is related to lunar effects. As far as I have read and seen wind forcing is the cause.
Ynestad 2006 “The influence of the lunar nodal cycle on Arctic climate.” [ICES Journal of Marine Science, 63: 401-420 (2006)] finds multi annual cycles of lunar impact on the Arctic atmosphere/ocean system, the strongest being 18.6 years. He also notes:
Why are the lunar cycles so dominant? The polar movement is only 3 to 15 m, and the lunar nodal tide represents only a small fraction of daily sea-level changes, so why are there dominant lunar nodal cycles in the time-series? The
answer lies in the fundamental difference between stationary and random cycles. Small changes in stationary cycles have great influence when they are integrated in time and space. Hence there would not be a fixed signal-to-noise ratio: the ratio, it would increase over time and space.
So it does not seem to me that lunar effects are likely at small timescales (days/weeks).
Indeed I have not found mention of lunar effects in ice movement off the Archipelago in all that I have read. I have read something suggesting lunar effects on ocean stratification, I accept that may affect the circum polar flaw lead (CPFL) – the “cracking” between landfast and sea ice. But once again I have consistently found that researchers refer to the impact of wind forcing in the CPFL.
I have personally noted that the movement away from the Canadian Arctic Archipelago that causes the sort of stress fractures Tenney has pointed to happens at times of the Arctic Oscillation having dropped to a low index – typically at the end of such a period. NOAA-CPC AO Index projection. As you can see from that link, the AO is currently negative and projected to go positive.
If you have counter-arguments, particularly references I’ve obviously missed that support your lunar hypothesis, please feel free to inform me.
#474 Nigel Williams,
There wouldn’t be substantial ‘left over energy’ as you suggest because this year there weren’t the unusual clear skies causing greater surface insolation, as there were last year. For myself what this year shows is that there has been no rebound from last year. Not in the sense of anything supporting hope of last year being a blip.
Compare and contrast the SST anomalies for Sept 2007
chosen words and Sept 2008. I know we’re only halfway through Sept 2008 but we’re now into the freeze season, it won’t get any warmer now.
I don´t understand why the difference between the NSIDC(SSMI) and IARC/JAXA(AMSR-E) extent data is growing each year, from 20.000 square km. in 2006 to 200.000 square km. in 2008:
NSIDC (SSMI) AMSR-E
2008: 4.520.000 km2 4.707.813 km2
2007: 4.140.000 km2 4.254.531 km2
2006: 5.758.000 km2 5.781.719 km2
#457 Eyal Morag,
Thanks for pointing that out.
Such a 24 hour appearance/disappearance of ice thick enough to register like that on AMSRE seems very unlikely to me (inherently improbable?).
I guess it’s something Bremmem AMSRE is “seeing” that isn’t there. QuikSCAT shows nothing (21/8/08 is day 234) and QuikSCAT is using radar not passive microwave. Cryosphere Today doesn’t show it in either their images or the Hudson Bay area graph. I can’t find any relevant images on
Your blog looks interesting. One question: What’s the difference between 21/8/08 A & B?
Another note of interest. If you have been following the drift of the North Pole web cam, it has been stuck between 83 and 84 north at the entrance to the Fram strait since mid July.
Basically little ice has been pushed out of the Fram strait this summer. This would explain the lack of ice off of North Eastern Greenland, as the ice there was melting in place without getting replaced with the floe from the strait.
So can we take it we saw a similar-to-last-year reduction in ice extent with significantly lower energy input due to ‘unfavourable’ cloud and wind conditions? More with less – not always good eh!
477 Cobbly, an existential question!
“Why are the lunar cycles so dominant?”
The paper perhaps acknowledges their existence .. Refer to my website http://www.EH2r.com
news section Realclimate article, you must scroll down the news section to look back at a full moon tidal wave. Captured but surely strange. Its ultimate effect was to push back the ice away from shore. I have many of such examples on a CD. Always captured at the full or new moon. Its easier now to see them with the link I suggested above. Ellesmere and Axel Heiberg NW coast got another ice push back at the full moon on about the 15th. I estimate them to be a wave with a strong current, perhaps raised from below the surface when there is a certain gravitational alignment. The wave effects appeared when ice movement (none or synergism) conditions were apt. They are predictable, made me a local prophet a few times. They are repeatable, and they are most certainly real (deadly).
I am not surprised that there is very few references about them, less than a handful of people watch them, now is the time to make them more popular. It will take a massive effort
to measure an track them closely, a paper fit for a big outfit. Mean time references? Basically most of the recent North Pole expeditions, I recommend Ousland, Alan Chambers (Royal Navy), and so many more out there, some have kept online journals. On frequent occasions full moon wave effects were noted pretty much from shore to Pole, but they can be really devastating on shore.
During winter leads show up like veins at most full and new moons as well.
Nigel, I would say, same melt with same heat, but the heat is not necessarily at 2 meters above the surface. The atmosphere is a 3d temporal challenge, Phil’s 300 watts/m2 IR radiation from buoy data intrigues. Was thinking about it last few days, that is a significant number, perhaps capable of having an effect on partially canceling the cooler surface temperatures due to summer clouds?
But not having volume data is really not helpful. Clarence’s 4400 km3 is the first I heard….
Re “NSIDC declaration is surely tentative all right”
How did NSIDC arctic sea ice news
on 16 September claim that
“However, we have now seen five days of gains in extent.” ?
In the F15 data linked by Clarence (see 478 and 448) which seems to agree to the 4.52 minimum announced, there only appear to be 3 days of increases after minimum on 12 September. If you count increases before the minimum on 12th there are at least 6 daily increases. If you use the 5 day average there is only one increase.
The only way I see of getting an answer of 5 from the F15 data is to count daily increases in the last 11 days which would seem a bit bizare.
JAXA data has 4 consecutive increases before the minimum in 2007 so I doubt that can be all that unusual. So I would have thought you would want at least 6 increases that have not reversed before calling a minimum which was earlier than the middle of September.
I am not sure that it needs a massive effort to to track the Arctic tides. You may know the following already, but I am sure others do not.
We tend to think of tides of waves of water flowing linearly backwards and forwards to and from the shore, but in fact they flow in circles in tidal gyres within tidal basins. See http://en.wikipedia.org/wiki/Image:M2_tidal_constituent.jpg
Since the Arctic ocean is a “closed circular basin” then an approximate tidal map could be produced by assuming that the centre of the Arctic ocean is an amphidromic point and drawing the maximum tide hour lines as lines radiating from that point every 15 degrees using your data for Ellesmere Island as a fixed point.
What do you think?
Thanks Alastair, well at least you acknowledge their existence :) . But this by-monthly tide surge appears to change location at times, peaking along the SW to NE side of the archipelago coast. The one I display on my website hits the SW corner the energy involved is absolutely huge. The effort needed would be to map it more reliably, and to measure its strength, they show incredible powerful destruction at times. Keep in mind the latest huge pieces of ice shelves leaving Ellesmere’s coast, to the amazement of the few scientists who observe them, and you begin to see that these mere tidal events hitting the same coast take more importance. Your map in essence shows the problem, the Arctic is barely displayed , may be there is a better map showing the Arctic Ocean. My curiosity is rather with ice dynamics, as to whether less coastal pack ice means a higher energy tidal impact.
Re your video: I cannot find a daily AO index for the period around 20 March 2000, the 3-month average from NOAA would be no good. However based on what I’ve seen I expect a negative AO index in the days around 20 March 2000.
What I see from the image sequence you referred me to are winds offshore from the Canadian Archipelago at the time the lead opens and cracks perpendicular to the coastal lead (parallel with the wind direction). Those offshore winds are from a low pressure system that passes from south of Banks Island. At the same time a lead further out from Banks Island (parallel to the coastal lead) opens and closes due to winds from a low pressure system passing on it’s Siberian side.
If I keep studying the Arctic (and I may not) I’ll collect more data this winter. From what I have to actually review this (I’ve not been deliberately following it before January):
All of these are approximate dates when the ice off the Candian Arctic Archipelgean coast moves away from the coast (lifting) instead of moving along it (shifting). The last is from AMSRE. The others from QuikSCAT timeseries, I prefer QS because it’s easier to see the movement from the perennial ice mass and in winter it’s less likely to be opening by melt, or complicated by melt widening a small initial opening.
7 January 2008, AO -ve
19 February 2008, AO +ve but on an upswing from -ve to a high +ve
4 April 2008, AO -ve
9 May 2008, AO -ve
18 May 2008 AO continuing -ve from 9 May.
3 July 2008, AO -ve.
In drawing up that list I’ve first got the dates of “lifting” movement, then checked to AO index.
In reviewing from the AO index to timeseries of QS and AMSRE the only -ve deviation of the AO below -1 not listed above is around 23 Jul to about 10 August, there is a possible ice-pack movement as in the above list, but the widest opening is 12 August, which again doesn’t fit. Otherwise I can’t find convincing incidents of “lifting” during period when the AO is +ve sustained or +ve falling.
If I were serious about this I’d use buoy vectors and do it properly. But I’ll leave the serious studies to the experts.
PS with regards Tenney Naumer’s image (dated 15/9/08) that sparked this debate off: the AO was also -ve from about 7 to 16 Sept.
Re: #484, #486
Arctic Tides are not as simple as they appear, as the astromical effect is enhanced by shelf waters.
The model you have suggested has been done, and the following article covers this.
There’s some ice volume data in IPCC AR4 WG1 4.4, but the time series of sea ice volume in the Arctic Basin is also just model-based (however a better model than the simple GDAS/GFS ice model) and ends in 1998. Table 4.1 says 19’000 km³ at the annual minimum and 25’000 km³ at the maximum. 4.4.1 states that nearly half of the total ice volume of the Arctic is in ridges.
Some GDAS ice data (every 5 days) is now available at http://seaice.bplaced.net/thickness/ . Note the anomalous values on 2008-04-03. Much ice has been destroyed in the model by data failure. Area and extent have been restored by the ice concentration data of the next day, but volume rebuilds slowly in the model, and some is still missing.
Re IR radiation: I think most of the downward IR is just upward IR reflected by clouds. That will distribute ocean heat from open water and leads to adjacent ice, but doesn’t add heat to the system. At least, downward IR is almost always less than upward IR in the GFS model. To display the data, go to http://nomad1.ncep.noaa.gov/cgi-bin/pdisp_gfs0.5.sh , select a run (forecast, not analysis), check “multiple variables”, then select “DLWRFsfc” as variable 1 and “ULWRFsfc” as variable 2 (both near the bottom of the list), select a time later than the initialization time (first values are undefined), choose “n hemi” as map projection and maybe a larger plot size than the default. The resulting plot shows downward long wave flux as colored map and upward long wave flux as labeled contours.
Thanks Clarence! I’ve calculated a 500 cubic kilometer difference between last years and this years melt. Although your number needs corrections as you have mentioned, I consider this the first tangible volume measurement in a near live scenario, so congratulations for the effort. Since there is 500 cubic kilometer less volume which has melted compared to last year, this estimate is not close enough to make it easy to say much. Another model must be used to see if last years extra sunshine, warmer seas and less albedo is responsible for the greater melt, in a formal physical “accounting” of all energies involved in the melts. Its never easy!
Looking back at both seasons, I would guess that there was way more heat energy
placed in the system than this year, another likewise comparison would evaluate the ratio of energies would be equal to the ratio of melts.
Downward IR is of course from clouds and will tinker with the model… I believe that there was some energy flux feedback which somewhat partially compensated for the lack of sun light directly heating the sea, but that remains to be proven. Many thanks…
LG I am not a member of AGU, sorry I cant read…..
The abstract is here
The authors have a web page at http://www.ims.uaf.edu/tide/ where Figure 4 shows the type of map I described.
There is also a paper describing a more sophisticated version of my model here http://www.esr.org/documents/padman/padman_erofeeva_04/2003GL019003.pdf :-?
Thanks Alastair, I printed out 1993 paper years ago but did not know about the 2003 one. I dont believe they relate to the specific full and new moon events. If you look at my web pages animation. that wave in particular does not happen at every tide. THe 93 paper misses the event all together and therefore the mystery continues.
Can you give me a URL for your web page animation? I could not find it when I quickly scanned your web pages.
I am making this up “on the hoof” so I won’t be surprised if I am proved wrong but here goes.
Looking at Figure 4, the tides to the north of Ellesmere Island are only about 10 cm high, but to the west the lines are closely spaced so the rate of change of water level will be higher there than else where.
Also as L.G, Norton mentioned tides are enhanced by a shelving sea bed. The best example of that is the Severn Bore where there is a surge at high tide caused by the narrowing effect of the estuary adding to the shelving sea bed. I wonder whether the fast ice near the shore will amplify the tide beneath it.
Lunar tides are caused by the difference between the gravitational force of the moon and the centrifugal force that exists and the earth and moon rotate about their barycentre. Within the Arctic circle this can result in only one high tide per day, and there and elsewhere with maximum tides during the equinoxes when the sun and moon are both pulling along the ecliptic plane.
That may account for your wave not happening at every tide, but if it is a bore, then it might be worth finding out about the Severn Bore’s periodicity which has been fully investigated.
Alastair, on website you scroll down EH2r news look for the title:
2008 Vertical disk diameters just reached 2nd place
there are 2 sun disk pictures displayed, the URL in question is on the “Real Climate” article which is just below. Is all right to try to figure this one out, a few have tried , actually not enough have tried!
Imagine the force capable of displacing about 10 cubic Kilometers of ice within a mere few hours.
Look for the tidal wave in black.
Wayne, when I click on that link (here) it just loops me back to the main page.
It works alright for me, but I am using Mozilla and it uses Quicktime which I have installed. You probably need to install that.
BTW this is the URL (here) points to:
I see that the next, and last this year, “Prospect”s for a 2 star (**) Severn Bore is on 29th and 30th September.
You wrote that some full moons do not create these surges. Do the missing ones correspond with the small bores on that chart?
Alastair, Right, sometimes they hit at the same place, sometimes higher up the coast, and at times the entire coast. In this case there was a hIgh pressure North of Alaska, a strong one, leaving an Imprint at its center, and a roving low pressure through blizzard system to the South, Moving towards the NE. The winds from the High Pressure favored closing leads off the coast, so the 5 to 10 mile opening is even more impressive.
The implication of these waves may be by considering how much impact they cause when the ice is thinner and smoother, or when there is no ice at all.
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