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2011 Arctic Sea Ice Thread

Sorry I think I wasn't clearer.

In Ben's post #136, how much of this energy is due to the additional warming from AGW rather that the typical (pre industrial) annual warming? I'm not contesting it, just wanting to be clear if we're talking about gross anual figures or the change to those figures.
 
Mikemcc said:
Sorry I think I wasn't clearer.

In Ben's post #136, how much of this energy is due to the additional warming from AGW rather that the typical (pre industrial) annual warming? I'm not contesting it, just wanting to be clear if we're talking about gross anual figures or the change to those figures.
Click to expand...

Well, we know we had a stable or even cooling situation up to 1850. Ice margins were well known from the search for a Northwest Passage. We saw ice expanding 15th century, corresponding with the failure of the Greenland colony.

We can say with a fair degree of certainty that the ice wasn't melting like this at any time in history (literally) and we have pre-historic proxies that tell us that that say the same thing.

PIOMAS specifically addresses anomaly, that is, we have a 1979-2001 baseline, established by the Satellite record, and we are seeing excursion of the system away from that average on the negative side.

We also see (right-hand graph in post #134) that we have an accelerating diminution of total volume.
 
Some of the pre-historic proxies come from whale genetics and whale parasite genetics. We know that Pacific populations of some whales and Pacific populations of some whale lice show that they have not been in genetic contact with their Atlantic counterparts in thousands of years, but we have very recently observed transits of these whales from one ocean to the other.
 
Mikemcc said:
Sorry I think I wasn't clearer.

In Ben's post #136, how much of this energy is due to the additional warming from AGW rather that the typical (pre industrial) annual warming? I'm not contesting it, just wanting to be clear if we're talking about gross anual figures or the change to those figures.
Click to expand...
Those 3 x 1020 Joules (more like 3.3) come from laws of Physics no matter it is a gain or a loss (only the sign changes), be it normal or abnormal. There is no label you can put on a specific chunk of ice and tell: this one melted because of any kind of warming or just because it's noon. In fact, every year some 15,000 to 17,000 km3 of ice are created and melted (in fact, roughly some 15,500 to 17,500 are melted). Such a process peaks some 140-150 km3 a day, and the source of it will continue to be energy radiated to space or energy got from the sun and low latitudes. Every year some 50 x 1020 J are added or subtracted from the Arctic-sea-ice system. This amount doesn't even reach the change in Earth's energy budget of having some 120 x 1020J more during southern summer, a fact that almost every denier clima____ ignore -as most dilettante warmers also do-. The problem is not 500 or 1000 cubic kilometres less as this is a self regulated system. The problem will be when we reach the ice-free point and the self regulated system changes. It's like having cash in the wallet, money in the bank and real estates that you can sell. Well, ice-free is an empty wallet, a mild example of much harder times that will come. But we still have ice and the system won't change until the fat lady sings.
 
BenBurch said:
Lowest recorded extent for this date;

http://www.iup.uni-bremen.de:8084/amsr/ice_ext_n.png
Click to expand...

That could have been be revised away. For the last 3-4 days I’d noticed a dip in this year’s ice extent that took it below 2007, but it seems to be gone and now looks like we are tracking right with 2007. Possibly very slightly below, but I don’t think the difference would be significant.

http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png
 
lomiller said:
That could have been be revised away. For the last 3-4 days I’d noticed a dip in this year’s ice extent that took it below 2007, but it seems to be gone and now looks like we are tracking right with 2007. Possibly very slightly below, but I don’t think the difference would be significant.

http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png
Click to expand...

The two seem to be around the same magnitude of difference. I think I did look after the revision.
 
BenBurch said:
The two seem to be around the same magnitude of difference. I think I did look after the revision.
Click to expand...

LOL it looks like it's changed again. When I posted the two lines were almost overlapping for the last week or so
 
It's probably because this year sea ice has become fragmented in an exceptional degree. Today just a fraction of it is packed ice. The reason may be a declining average thickness. The apparent thickness (division of sea ice volume by sea ice extension) by June 30th has dropped from 1.65m in 2007 and 1.45m in 2010 to 1.34m this year (and it was losing 2 cm per day by the date). Anyway, part of the area lost in the last 12 days is ice packed by wind. That makes melting more difficult, so this together with cooler weather for the second half of July makes me expect a slower rate of loss so we can be above 2007's curve any day. But fragmented ice at early dates appears to be the scenario for future springs and summers, so a(n almost) ice-free Arctic may be the sudden development to come during next years -by the next ENSO event?- but not this year, thank goodness.

By the way, during next days you may see some tweak in this year's plot and recent trend for instrumental reasons.
 
BenBurch said:
Which direction do you think?
Click to expand...
I think we'll have revised extents up about 200 or 300,000 square kilometers. Last July 11th there were disparities up to 700,000 square kilometers among different sets of values. For instance, we always refer here this figure, but the very same NSIDC has MASIE. If you compare today [14Jul2011] that image with this one, you'll be watching two different Hudson Bays: one with little ice, but bits of packed ice in James Bay; the other one with an ice coverage of at least one fourth of the total area, but with an ice free James Bay. The value from MASIE for July 12th (day #193) for Hudson Bay Area is 444,815.25 Km2 (how they got their values with seven significant figures is a mystery to me). By the way, MASIE shows a growth of the ice extent: from 8415956.72 to 8490688.89 Km2 between July 10th and July 12th (days 191 and 193) and they must be right otherwise the wouldn't write nine significant figures ;).

I didn't look for an explanation about these disparate values, but it is evident to me that we have probably now the maximum extent of sea ice-water borders -I'd say some 20,000 to 30,000 km-, so the resolution of 25 Km to 4 Km and their different techniques to determine what is less than 15% coverage and what's not might be the cause. Everyone look a bit adrift on their own floe and I bet they are trying to solve the puzzle now before it melts below their feet.

A couple of days ago, similar criticism got me the label of diehard malafide denier from one of the writers in one egregious site devoted to promote healthy skepticism and good information. I hope this won't repeat here, because those creatures matching that label will continue to be clueless may I critique or not, what begs the question of how many clueless creatures are this side of the border. Sad but true.
 
I usually check out the maps at Cryosphere Today (University of Illinois)
http://arctic.atmos.uiuc.edu/cryosphere/NEWIMAGES/arctic.seaice.color.000.png
Ice in Hudson Bay has been declining rapidly in the last week, The maps are not as far apart as you think. The one with more ice looks like it’s just a few days older.
http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=07&fd=08&fy=2011&sm=07&sd=10&sy=2011
It’s harder to see in the lower resolution map, but there was a pretty big area of Hudson Bay that was “blue” (~20% ice coverage) just a few days ago and that does count as extent. What I suspect you will see is the melt slow now that Hudson Bay is nearly ice free, but there is still a big area of rapidly melting ice SW of Greenland. (This is what Hudson bay looked like on the larger map just a few days ago.)
 
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