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Patrice Pustavrh

Hi Neven. First, I'd like to congratulate on your nice, well documented effort. But on the other hand, I have a question about weather charts and their correlation to ice movement. Since it is known, that areas of low presure circulate air in anti clock-wise direction and areas of high pressure do this just opposite, could these images be useful for ice displacement prediction ?

Neven

Patrice, welcome.

I'm no expert, far from it, but yes, I believe sea level pressure systems are elemental for ice displacement. I'm sure that PIPS or AARI (unfortunately still down and not answering my mails) ice displacement forecasts are based primarily on such weather forecasts as described in this SIE update.

But there has to be a stable situation for circulations like the Beaufort Gyre to get going. Perhaps we will see it again if that high pressure area forms over the Beaufort Sea.

Of course, as ice gets thinner, it can be moved around more easily and is thus more susceptible to winds caused by cyclones and anti-cyclones.

Other people probably know more about this, so feel free to weigh in.

Kevin McKinney

Color me crazy, Neven, but I'm not so sure about the decline in melt rate throughout the month, since the measure in question is actually extent.

Surely the volume melting will decrease as daylight hours shorten--but with concentrations relatively low, I wonder if extent may continue to decline relatively quickly for a bit longer? I guess my imagination "thinks" that the extent/area ratio is due to "normalize" a bit, as the season winds down.

A muddled comment, I'm afraid, but perhaps you see what I'm wondering about.

Neven

Kevin, always nice to have you commenting, muddled or not.

Of course in theory the melt rate could remain high, but 2008 had the highest rate, I believe, with over 70K per day. It will be very difficult to top that.

I think - but I'm wrong all the time, so... - that if we get that high pressure cell going over the Beaufort Sea we will see some major compaction and thus a high extent melt rate until all the ice is pushed together (possibly as high as 2008). If the high doesn't get produced, there could still be a extent rate considerable enough to end below 5 million square km, but it will more difficult.

We'll see, day from day.

Neven

BTW, the weather models are forecasting the high-pressure area to start a day earlier, on Monday August 9th. ECMWF in particular is expecting the anti-cyclone to be fairly strong, with a SLP of 1035 hPa by this time next week. Exciting.

Neven

Things have slowed down again somewhat. Preliminary melt of 67,343 square km reported by IJIS.

Kevin McKinney

I haven't checked the various basins on CT, but the Archipelago has been rather cool last couple of days, so that presumably has cut into melt there. (IIRC, there was even some snowfall.)

But that's due to change again, with several very warm sunny days in the forecast for most of the Archipelago.

siili

Zhang has updated his forecast based on the PIOMAS model, and he's holding steady at 4.8M(km^2) http://psc.apl.washington.edu/zhang/IDAO/seasonal_outlook.html and since the forcing is historical averages from the latest seven years, and i assume that the forcing this year has been rather week, to keep the estimate, the starting state of the ice must have been worse than he thought before.

siili

For a few days i have been following a moving station reporting wind direction on Kölns weather map above the New Siberian islands, and today it arrived at the last obstacle remaining in the northen searoute outside Taimyr, and when i checked the shipstracker it turned out to be Mother Russia herself, the atomic icebreaker.

Maybe this will help the russian yacht which has been held up there for over a week in an attempt to be the first to circumnavigate the arctic in one year, and if the Norse are quick they can follow?

But it seams that both Russia and China are keeping secret about what they are doing in the arctic ocean since neither Yamal with Academic Fedorov out on a 100day exploration nor the Snow Dragon are reporting positions to
http://www.sailwx.info/shiptrack/shiplocations.phtml at least.

siili

Sorry to use up the bandwidth with garbage( the commodity, not the band), but on the other side of the mirror, the lead story at the moment is that the find of HMS Investigator demonstrates that in the NWP nothing has changed in 157 years! If only Franklin, McClure & followers would have lived in the twilight zone, things would have been so much easier.

FrankD

Just looking at Ron Lindsay's prediction - this has been dropping every month since April, while the error has been tightening:
End of:
April: 5.12 +/-0.42 (R2 = 0.84)
May: 4.44 +/- 0.39 (R2 = 0.84)
June: 3.96 +/- 0.34 (R2 = 0.79)
July: 3.7 +/- 0.3 (R2 = 0.76)

His statistical model is strongly dependent on G0.4 and G1.0 (the area of ice that is <0.4m and <1.0m thick, respectively). Like several of us here, he concludes that while extent improved over July, the ice has significantly thinned. For his model that means a large area vulnerable to melting, export or compression, all of which will drop the final extent.

The key areas for him are:
the Kara Sea - virtually ice free now, when it typically has 250,000 sq km at this time,
the Beaufort Sea - with half the usual ice cover for this time,
and the area in and north of the Canadian Archipelago - which on paper isn't doing too badly, but when you look at the satellite pix is in bad shape, I think.

His prediction has at or around the lowest of the ensemble gathered by SEARCH, and I'm pretty sure will be again when their August report comes out.

Neven

Bets are being hedged and the hoi polloi prepared for the eventuality minimum ice extent happens to fall below 5 million square km after all. I have already discussed this with Patrick (Lockerby) at the start of the melting season.

There is a strong correlation between melt rate and article rate on the other side of the mirror. When the ice is doing what they want it to do, ie melt slowly, they limit themselves to weekly updates that shows how right they have been (even though their narrowly focussed analysis rests mostly on PIPS ice thickness figures, DMI temps above 80N and the CT comparison page). Once melt rates pick up, they intersperse their updates with shoddily written and thought out articles questioning the way data is processed etc. The behaviour gets more frantic as the ice melts more heavily.

If extent starts to fall rapidly, we will soon hear about how the Chinese already sailed the NWP in the 15th century. Mark my words. If extent falls below 5 million square km, we will see a seamless transition/retreat towards historical records and 'it's all cyclical, AMO/NAO switch will soon kick in, La Niña will bring more recovery'-blahblah.

Neven

Holy mother of God, I didn't expect to be proven right so fast.

Neven

There, Patrick says it too. :-p

logicman

Some pseudo-skeptics go a step too far:
http://www.science20.com/chatter_box/blog/spitting_graves

btw - your " I didn't expect to be proven right so fast" hyperlink shows rel="nofollow" instead of http= or whatever.

Neven

Patrick, I didn't link that properly, and perhaps it's for the best. It was leading to a commenter on a recent 'NWP open-HAHAHA'-article on WUWT, saying:

"Didn’t a Chinese Admiral [+ massive fleet] pass through the North West Passage in the mid 1400′s?"

FrankD

Oopsie!

Just noticed that in my posst above, the R2 values for Ron Lindsays predictions are in reverse order. Lindsay examines several variables seperately and then uses whichever has the highest R2 to generate the final prediction. The correct details are:
April: 5.12 +/-0.42 (R2 = 0.76)
May: 4.44 +/- 0.39 (R2 = 0.79)
June: 3.96 +/- 0.34 (R2 = 0.84)
July: 3.7 +/- 0.3 (R2 = 0.84)

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