http://arctic.atmos.uiuc.edu/cryosphere/

http://nsidc.org/news/press/2006_seaiceminimum/20060816_arcticseaicenews.html

http://www.abmcdonald.freeserve.co.uk/north.htm

http://www.uni-koeln.de/math-nat-fak/geomet/meteo/winfos/arcisoTTPPWW.gif

http://nsidc.org/data/docs/daac/nsidc0046_nh_ease_snow_seaice/browse/viewer.html

http://www.arctic.noaa.gov/gallery_np.html

http://www.ncdc.noaa.gov/oa/climate/research/2007/apr/global.html#Introduction

Please keep this thread on topic

We are currently in the period of fastest melt in the Arctic, though the melt is never a linear process, as the amounts in the Arctic basin clearly show. Then difficulties of seperating slushy ice from other ice types often explains the changes. Amounts of ice are running, just about, neck and neck with last year and the anomaly is at the lowest ever. If we do not get the same kind of unusual, stormy conditions as last year, I feel we will get a record low.

http://arctic.atmos.uiuc.edu/cryosphere/

SWZ

I'm not entirely convinced by the data over the last few days as it would imply an increase in the Arctic Basin in the last 2-3 days. I suspect the big drop was anomalous and the current levels shown are accurate (i.e. a steady downward trend ratherthan a massive overnight drop and then recovery). That is however pure conjecture on my part!

I think you were right Michael. As I've said before, during the melt season (or freezing season, for that matter) any anomalies during the season have to be taken with an enormous spoonful of salt. Arctic conditions vary through the seasons and what happens, on a weekly, or a monthly, basis, during the seasons only has local effects. The outcome at the end of the melt, or freeze seasons, for the whole Arctic is what counts. talking about current conditions speculating on the final figure, is fun though, as is figuring out why local areas are above, or below the average.

To bring us up to date and speculate; Arctic Sea ice levels are below what they were this time last year. The overall anomaly must be close to record figures and, unless we get exceptionally cold summer temperatures, or particularly stormy conditions, I'd expect there to be lowest amount of Acrtic Sea ice ever reporded by early September, when the freezing season will begin again. With the potential for this record low, I also expect the NW passage to be open this year.

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.365.jpg

SWZ

 

Is it true that june07 saw the largest loss of sea ice ever recorded in a single month?

The negative anomaly has turned close to record-breaking and the drop in ice area steepened during June, from a situation where the ice was above last year's comparative levels, to a situation where is it presently below last year's levels, therefore the amount of ice that melted was high. I don't know whether is was record-breaking, rc1.

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.365.jpg

Ice-thickness comes into this as well and not just ice area. To estimate ice thickness, scientists have relied on submarine measurements in the past, but the sampling of these thicknesses was not as systematic, or as regular as would be liked, for obvious reasons.

Launched in 2003, Icesat, a NASA instrument, already sends back some satellite information, but CryoSat-2, scheduled for launch in March 2009 will help further with this (fingers crossed that it doesn't suffer the same fate as CryoSat which was lost after a launch failure!).

http://www.sciencedaily.com/releases/2007/03/070312111341.htm

Presently, judgements of the amount of Arctic Ice are made mainly with reference to extent. 

SWZ

There seem to be contradictions again between the sea ice index score on NSIDC for June, and the cryosphere today charts. They're not strictly a like-for-like comparison but even so the difference appears large.

http://nsidc.org/data/seaice_index/images/n_plot_hires.png (you may need to refresh to bring up June)

versus:

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.anom.jpg

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.365.jpg

Best wait until the end of season to make any judgments, I think.

I'm still baffled by the relatively high (and increasing) ice concentration in the Canadian archipelago in conditions that are up to 10C above average and well above freezing. Must be local circulation anomalies piling the stuff up.

SW Zephyr:

The negative anomaly has turned close to record-breaking and the drop in ice area steepened during June, from a situation where the ice was above last year's comparative levels, to a situation where is it presently below last year's levels, therefore the amount of ice that melted was high. I don't know whether is was record-breaking, rc1.

SWZ

I thought it was record breaking because it was said here and a chart was also shown:

http://www.netweather.tv/forum/index.php?showtopic=38352&st=153&start=153

Read the bottom of the page on that link.

 

rc1:

SW Zephyr:

The negative anomaly has turned close to record-breaking and the drop in ice area steepened during June, from a situation where the ice was above last year's comparative levels, to a situation where is it presently below last year's levels, therefore the amount of ice that melted was high. I don't know whether is was record-breaking, rc1.

SWZ

I thought it was record breaking because it was said here and a chart was also shown:

http://www.netweather.tv/forum/index.php?showtopic=38352&st=153&start=153

Read the bottom of the page on that link.

It could be, rc1, but the graphs posted on there show the anomaly from the mean, not the amount of ice that melted during June. The two are probably linked, but the record-breaking anomaly does not in itself, point to a record-breaking loss of ice in June. The change, over the month, in the comparison to last year's levels is a better indicator, but even that is not conclusive. I don't know where the poster Iceberg, got that statement from; it may well be correct, but without a link I can't yet judge and I haven't found anything to confirm it - though I suspect it may be true.

SWZ 

The cryosphere today charts continue to show steady ice loss, at about the rate you'd expect for the time of year (but from an abnormally low base). Can't seem to get the page up to link it now.

The 2m temperature forecasts for the Arctic basin over the next week show any large patches of sub-zero temperatures around the Siberian islands shrinking and dissipating, and the heat continuing in the Canadian archipelago. I expect quite a rapid shrinkage over the next week. Despite the current heavy ice over the Canad. arch. it looks odds on that the NW passage will open again this year. Look at the 10-day temp forecast:

http://www.wxmaps.org/pix/temp2.html

Parts of the NW territories and islands are, depressingly, warmer than most of the UK.

 

Tim S:

Parts of the NW territories and islands are, depressingly, warmer than most of the UK.

 

Yes, on the shore of the arctic ocean in northern canada temps got into the high twenties according to this:

http://www.accuweather.com/news-top-headline.asp?partner=accuweather&traveler=0&date=2007-07-12_16:22&month=7&year=2007

Read to the end of that article where it mentions it.

rc1:

Tim S:

Parts of the NW territories and islands are, depressingly, warmer than most of the UK.

 

Yes, on the shore of the arctic ocean in northern canada temps got into the high twenties according to this:

http://www.accuweather.com/news-top-headline.asp?partner=accuweather&traveler=0&date=2007-07-12_16:22&month=7&year=2007

Read to the end of that article where it mentions it.

It's not unheard of though. With continental air masses NWT gets very large temperature ranges with many parts of it being consistently warmer than here at least during the summer.

When they get warmer than average and the south of the UK get cooler than average conditions in summer I'd be surprise not to see it being warmer there. The mean maximum in Fort Smith in southern NWT (where I spent Christmas) is 24ºC at this time of the year comapred with 22.5 or so in London.

Even futher north in the likes of Tuktoyaktuk (great name eh? ) such high temperatures aren't as rare as you'd think (although it has been anomalously warm I think in the region of Sachs Harbour)

True Michael and I believe 100F has been recorded within the Arctic Circle in northern Sweden.

SWZ

There was a piece on N24 yesterday about some chap that swam in open water 'at the North Pole' for a distance of 1 KM, is that likely? I know there's only a limited number of stellite images of the pole but from what I've seen it looks fairly well iced up to me. I do wonder if the Beeb have been a bit loose with the term 'North Pole'.

No, he's been in the news a lot. A pretty incredible achievement, recognised by the Guiness Book of Records. 18+ minutes in water at -1.8C! We'd die very, very, quickly!

There is often open water at the North Pole these days. The cracks in the ice are not easily picked up on lower resolution Satellite photos. The real difficulty is in saying how much open water there is now, compared to years gone by. I suspect there is more, but that would be hard to verify.

SWZ

Peter:

There was a piece on N24 yesterday about some chap that swam in open water 'at the North Pole' for a distance of 1 KM, is that likely? I know there's only a limited number of stellite images of the pole but from what I've seen it looks fairly well iced up to me. I do wonder if the Beeb have been a bit loose with the term 'North Pole'.

I'm not sure Peter. To be honest in a vast sea of ice being constantly moved around are cracks really that unusual or even a sign of warming? The ice hasn't melted as such but broken:

"Throughout the region within the Arctic Circle leads are continually opening and closing due to the direction and intensity of shifting wind and ocean currents. Leads are particularly common during the summer, when temperatures are higher and the ice is thinner."

For example: http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/modis_north_pole_lrg.jpg

 

And also:

"The wind stress which drives the sea ice through frictional drag is integrated over a large area - it has been estimated that in concentrated pack ice a piece of sea ice responds to wind fields integrated over a distance of 400 km upwind. Therefore a large-scale divergent wind field, created by an appropriate pressure pattern, can also create a divergent stress over a large area of icefield. Since ice has little strength under tension, this divergence can open up cracks which widen to form leads. In winter leads rapidly refreeze because of the enormous temperature difference between the atmosphere (typically -30°C) and the ocean (-1.8°C). "

http://www.arctic.noaa.gov/essay_wadhams.html

So basically the cracks are not unusual although as Paul suggests the extent may have changed but I have no way of verifying that. It just seems that the cracks caused by pressure freeze up again in winter after they form whereas in summer they don't (unsurprisingly!)

Thanks both, very interesting, I didn't think about the cracks in the ice rather than wholesale melting.

The whole gist of the news items was that being able to swim at the North Pole now was solely down to global warming and the melting ice, it would be interesting to know if these cracks used to appear in the colder 60's, 70's and 80's.

It may be a little subjective but the following excerpt from an aricle in the LA Times in 2000 discusses this very issue:

"The sea ice that waxes and wanes with the seasons at the poles has long been seen as a window into the Earth's complex climate system. Any global changes are likely to be most visible--and extreme--on the frozen edges of the Earth that are most vulnerable to warming.
     But that ice has long frustrated legions of scientists trying to capture its vagaries. Icebreakers moving through the region and taking measurements are rare, and nonexistent in the winter when the pack ice freezes tight.
     Submarines that once traversed the pole and measured ice thickness from below have largely been decommissioned since the end of the Cold War. And satellites have long been stymied by thick, white Arctic clouds that look, from space, so much like the ice itself.
     But a powerful new satellite is giving scientists at the Jet Propulsion Laboratory their first close-up view of the tortured surface of the Arctic Ocean. And the initial images released this week are already causing a stir: They confirm scientists' notions that while warming appears to be affecting the entire Arctic region, cracks exposing water at the North Pole are not a clear-cut result of global warming.
     The satellite sees through clouds and the long polar night, takes images with a resolution of less than an inch, and allows scientists to view sequential images of the ice like time-lapse films.
     "It gives you a picture of how the ice cover is moving about," said Drew Rothrock, a sea ice researcher at the University of Washington's Applied Physics Laboratory. "It's amazing what you can figure out looking down from space."
     What do they see? Cracks. Lots and lots of cracks. Some more than 1,200 miles long and most several miles wide. "They go from one part of the Arctic to another," said Ron Kwok, who heads the polar remote sensing group at JPL. "There are thousands of them all over the place."
     Though dramatic and longer than previously believed, the cracks are not clear evidence that global warming is occurring, he said. Scientists have long known that such cracks fracture the Arctic ice, a skin that ranges from a few inches to 10 feet in thickness.
     Knowledge of the cracks has many oceanographers this week pooh-poohing recent eyewitness reports of open water at the North Pole. The reports gained widespread media attention and were presented as evidence that the effects of global warming are now extensive.
     Passengers on a tour ship returning from the North Pole last week reported a mile-wide patch of open ocean at the very top of the Earth. The open water prevented the tourists from having their pictures snapped at the geographic North Pole, and astonished the veteran Russian captain piloting the icebreaker carrying the tourists.
     But scientists who have been studying North Pole ice and its vagaries for decades found nothing astonishing in the report.
     "There are mile-wide cracks all over the Arctic in the summer," said Rothrock.
     JPL's Kwok said there is "nothing special" about cracks at the North Pole, because they can occur anywhere within the Arctic ice. Members of his group had not seen current satellite images of an opening at the pole this summer because they had not yet processed recent images. They hope to check the new images in coming weeks.
     Kwok's team will continue monitoring changes in the sea ice, particularly patterns of cracks, to look for evidence of global warming. He hopes the time-lapse images of ice forming will allow his team, for the first time, to estimate ice thickness from space. Although the polar oceans may seem static, they are actually violent places with ice shifting, groaning, breaking and piling up on a daily basis.
     "If there are any changes in the global climate, it's going to be reflected in the sea ice--at the poles," he said. In turn, those changes in sea ice greatly alter climate.
     Open areas within the ice, or polynyas, allow the ocean's heat to escape into the atmosphere. They also mean that less solar radiation is reflected away from Earth.
     Though the new images are not proof of any change, Arctic temperatures have been rising steadily. A review of 40 years of polar research published last month shows that temperatures in some parts of the Arctic have risen by 11 degrees in the past 30 years. In addition, snow and sea ice cover have dropped and many glaciers have shrunk.
     In contrast to the cracks, this overall warming and shrinking is thought to have its roots in global warming. "

Peter:

Thanks both, very interesting, I didn't think about the cracks in the ice rather than wholesale melting.

The whole gist of the news items was that being able to swim at the North Pole now was solely down to global warming and the melting ice, it would be interesting to know if these cracks used to appear in the colder 60's, 70's and 80's.

Ice thickness is known to have declined, the Arctic has also warmed. I can't see how there could have been as many large leads/polynyas in the recent past. However, I suspect the answer is unknowable since few people would have visited/observed the North pole even as late as the 60's?

But, I better say no more for fear of being accused of dragging the thread in the direction of a certain topic   

I agree with all of you; it is probably going to remain an unknown. As far as the influence of GW goes, the declining ice minimum over the whole Arctic in the last 20 years is the key, not the cracks at the North Pole, even though the swim was done to highlight GW. It still doesn't take away this guy's achievement though. Ikm in water that cold was a life threatening swim!

SWZ