Polar Ice Extent

[Gray-Wolf]

Hi Stew!

Well I'd expect to see the 'slowdown' in ice loss delayed and the seasonal melt extend (if I'm on the right track about how the collapsing ice used to 'prop up' final ice extent figures) so the 'rate of ice loss' may continue quite quickly throughout Aug/early Sept?

Edited July 20, 2010 by Gray-Wolf

[VillagePlank]

We now have good access to sub data back into the 50's (since the end of the cold war) and instrumental data back to the turn of the 20th century (I'm led to believe)

Yes - but the data before 1950, I read somewhere today, is meant to be, ahem, dodgy and unreliable.

[Gray-Wolf]

So then , V.P., I start to listen to the 'changes' that indigenous folk are witnessing (along with mainstream science these days it seems?) as they rely on their knowledge to survive so I'd expect tales of times when similar conditions were met and how to deal with them?

If they have no 'folk law' about wasps (and so need the U.S. Govt. to educate them as to their dangers) then you have to ask 'why?'

The same with their winter ice hunting and how they are now finding it impossible to get out on the ice (arctic sea smoke tells them there's open water out there etc.)

Or weather itself with changes that once took a couple of days to occur so the 'signs' gave them plenty of warning of approaching weather 'types' now happening within hours of seeing the 'signs'.

As you know I'm fully convinced (and so is the majority of the 'science' I've read) that these are 'novel' changes in the Arctic. I believe we have not seen this in many thousands of years (which makes us very fortunate/unfortunate to be able to witness it!).

[Devonian]

Yes - but the data before 1950, I read somewhere today, is meant to be, ahem, dodgy and unreliable.

Less complete are better words? I don't see why it would be dodgy - though it depends what you mean by dodgy...

[VillagePlank]

Less complete are better words? I don't see why it would be dodgy - though it depends what you mean by dodgy...

I've looked for it - but for the life of me I kind find where I read it. I must retract that comment then - until (and if) I find where the source is.

EDIT: Found it - the premise is that before the satellite record (1979) data gets sparse but there is a reasonable amount of shipping data and ice records to go back to the 1950s (1953) Before that 'the historical record is less reliable'

Here

So ... yes, 'less complete' is a better way of putting it - but 'dodgy' seems just a good, to me

Edited July 20, 2010 by VillagePlank

[Gray-Wolf]

I've looked for it - but for the life of me I kind find where I read it. I must retract that comment then - until (and if) I find where the source is.

Welcome to my world!!!!

[sunny starry skies]

"Less reliable" is fair enough, but don't conflate that term with "unreliable" - there is a reliability spectrum out there! My take would be that we have observations, maps, documentary sources including reports from various expeditions in the 19th Century and early 20th Century (for example Northwest Passage), as well as traditional knowledge. All point to an extensive thick pack, similar to the 1939 sea ice minimum map below:

Taken from Patrick Lockerby's latest post - what is notable is that the map is for summer minimum extent, and there are gradations from 'permanent pack' through 'perennial pack' (what we now have only in the central basin). This is the largely sound mass of ice that remained coherent, throughout the year barring temporary leads and polynyas, and was many metres thick. The maximum extent was rather larger than that, and according to historical sources periodically, and quite often, reached Iceland during the previous centuries (see Astrid Ogilvie's work). Taken all together, we can see that while we don't have nice detailed annual maps of sea ice extent (certainly the maps would be 'less reliable'), we have absolutely no evidence for less than a substantial, coherent body of sea ice, similar to that mapped in the 1930s, in any of the past two centuries.

http://www.science20...2010_update_3_0 [Lockerby's post]

What we have now is nothing like that, and the late 20th Century observations of decline coherently fit the transition from a strong multi-metre thick cap down to the shattered brash of floes that now exists, and is wildly sensitive to large melts or ice exports, given favourable weather. Nothing to do with fabled ocean cycles (oceans are warming as recorded by rising heat content and by sea level rise from thermal expansion), but the pattern fits neatly with the observed rise in ocean temperatures and rise in Arctic air temperature.

sss

Edited July 20, 2010 by sunny starry skies

[Gray-Wolf]

Thanks for that SSS!

I can understand why we wouldn't want to see the Arctic decline as we do but you cannot live your life out on hopes alone?

We are seeing a remarkable change in the North and it promises to spread it's influence throughout the globe over time.

I believe we will all wonder why we quibbled about the amounts that this world has altered over the past 100yrs once these Arctic feed down impacts begin to properly manifest.

Sadly ,before we can figure what impacts may arise we need accept that this scale of change is really on the way!

[jethro]

The latest from Igor Polyakov:

http://soa.arcus.org/sites/soa.arcus.org/files/sessions/2-1-observations-arctic-change/pdf/2-1-4-polykov-igor.pdf

"The temperature of Atlantic Water of the Arctic Ocean was, on average, 0.24°C warmer in 2007 than in the 1990s. Recent observations suggest that the eastern Arctic Ocean is in transition towards a cooler state."

[Yorkshiresnows]

Over recent years it's become apparent that we have a reasonable picture of Arctic decline running back over 100yrs? I think Oxford Uni are the folk that have the papers using this data(?) so we shouldn't be limiting ourselves to merely the Sat. era.

We now have good access to sub data back into the 50's (since the end of the cold war) and instrumental data back to the turn of the 20th century (I'm led to believe)

If you need more info on our 'info' why not approach Mark Serreze at NSIDC ?

I'm sure (though very busy!) he'd be pleased to bring you up to speed on how much we 'know' and why we have such concerns for the future.:lol:

No need dude, ....... nobody has accurate data prior to 1979, lots of suppositions, but little else .... as you well know.

Arguably the 1930-s to 40s could be classed as poor for arctic ice ...... big increase peaking in the late 70's .... decrease and then rapid decrease recently...... but lets not go through all this again.

Lets see what happens with the turn of the PDO. I see that arctic temperatures are now hovering around freezing and remain below normal for the time of year and Global tempeartures have now dipped below last year for the first time. Is this the beginning of a second half trend ...... guess we'll soon find out.

(links to the above on Accuweather, or The AQUA satellite area).

Y.S

Edited July 20, 2010 by Yorkshiresnows

[Gray-Wolf]

No need dude, ....... nobody has accurate data prior to 1979, lots of suppositions, but little else .... as you well know.

Arguably the 1930-s to 40s could be classed as poor for arctic ice ...... big increase peaking in the late 70's .... decrease and then rapid decrease recently...... but lets not go through all this again.

Lets see what happens with the turn of the PDO. I see that arctic temperatures are now hovering around freezing and remain below normal for the time of year and Global tempeartures have now dipped below last year for the first time. Is this the beginning of a second half trend ...... guess we'll soon find out.

(links to the above on Accuweather, or The AQUA satellite area).

Y.S

Here's some accurate data then y.s., JAXA's provisional melt figure for today is 131,719!!!

I know we posted some 30,000 last week but that was with the pack 'stable' with the synoptics keep ice on station across the basin. I said at the time that the ice was now degraded and in small chunks and not large plate floes so some of the past 2 days losses are just that and not ice compression or loss through the 'exits'.

If central ice is now able to free up over 85% of the waters around then what of the rest of the season's melt?

EDIT:

http://nsidc.org/arcticseaicenews/

above is the second 'report' of the month explaining the 'slow up' in melt rates . They also highlight the low concentrations of ice I've been pointing out and ,guess what???, they use MODIS to show it as real and not the microwave sensors picking up sea ice melt!

EDIT,EDIT;

http://ocean.dmi.dk/...te/index.uk.php

and for those in a love in with 2m air temps here's what the ice is sat in! ( remember ,about -5c for sea water to 'freeze')

Edited July 21, 2010 by Gray-Wolf

[jethro]

Don't you all think it's fantastic that Polyakov (one of the leading Arctic experts) thinks that the warming looks to have peaked and that we're now heading towards a cooler period?

[Devonian]

Don't you all think it's fantastic that Polyakov (one of the leading Arctic experts) thinks that the warming looks to have peaked and that we're now heading towards a cooler period?

It's good news if he's right. However, I think the physics, as I understand it, is right and thus I think we'll continue to see ice decline in the Arctic (and other climate effects due to human activity).

[noggin]

Don't you all think it's fantastic that Polyakov (one of the leading Arctic experts) thinks that the warming looks to have peaked and that we're now heading towards a cooler period?

I DO, JETHRO. I AM SHOUTING BECAUSE I AM DEAFENED BY THE SILENCE!

[jethro]

It's good news if he's right. However, I think the physics, as I understand it, is right and thus I think we'll continue to see ice decline in the Arctic (and other climate effects due to human activity).

Well he was accepted as the expert voice by the IPCC so I tend to accept his findings, plus only a relatively small portion of the Arctic warming has ever been attributed to humans. Things are looking up

[Devonian]

I DO, JETHRO. I AM SHOUTING BECAUSE I AM DEAFENED BY THE SILENCE!

What silence?

I'm here, I replied. Who else is here to reply? Have a bit of patience...

[Gray-Wolf]

I take it you just ignored the current SST anoms across the region he's talking about that I posted up for us all? I make it 5c above normal at the mo and I ain't putting any flags out on the strength of that.

Not to be dismissive but how have the arctic systems been working over the past 5 years? (on the back of 15-30yrs of oddness) I seem to remember a record AO in Feb and high ones in Jan / Dec too! Seeing as the AO will/is the most obvious 'start point' for the A.A. to impact I think Igor is a little behind the times. The 'surprises' science has been dealt by the Arctic over the noughties has me thinking we're a little behind the game in both research and modelling?

Should the PDO-ve ever get into gear any intensification of the AO in the same period will merely add to the problems in the basin with ice thickness pegged and ice losses throughout winter (though glorious for snow lovers here!!).

Edited July 21, 2010 by Gray-Wolf

[Yorkshiresnows]

Well he was accepted as the expert voice by the IPCC so I tend to accept his findings, plus only a relatively small portion of the Arctic warming has ever been attributed to humans. Things are looking up

Hi Jethro,

Yes, I am pleased with this news. As you know, I am a believer in the cyclical nature of oceanic phases coupled to an atmospheric response and the possibility that like waves, certain cycles can peak together to provide a notable effect on climate. This I believe is the cause of much of the 20th century warming.

As the cycels turn, we should see an effect at the polar region, that is most affected by predominant PDO states (at the turn of the last 30 year PDO cycle Alaska prety much warmed up immediately) ...... but, .... as ever, time will tell.

Y.S

[Gray-Wolf]

1990 -0.30 -0.65 -0.62 0.27 0.44 0.44 0.27 0.11 0.38 -0.69 -1.69 -2.23

1991 -2.02 -1.19 -0.74 -1.01 -0.51 -1.47 -0.10 0.36 0.65 0.49 0.42 0.09

1992 0.05 0.31 0.67 0.75 1.54 1.26 1.90 1.44 0.83 0.93 0.93 0.53

1993 0.05 0.19 0.76 1.21 2.13 2.34 2.35 2.69 1.56 1.41 1.24 1.07

1994 1.21 0.59 0.80 1.05 1.23 0.46 0.06 -0.79 -1.36 -1.32 -1.96 -1.79

1995 -0.49 0.46 0.75 0.83 1.46 1.27 1.71 0.21 1.16 0.47 -0.28 0.16

1996 0.59 0.75 1.01 1.46 2.18 1.10 0.77 -0.14 0.24 -0.33 0.09 -0.03

1997 0.23 0.28 0.65 1.05 1.83 2.76 2.35 2.79 2.19 1.61 1.12 0.67

1998 0.83 1.56 2.01 1.27 0.70 0.40 -0.04 -0.22 -1.21 -1.39 -0.52 -0.44

1999 -0.32 -0.66 -0.33 -0.41 -0.68 -1.30 -0.66 -0.96 -1.53 -2.23 -2.05 -1.63

2000 -2.00 -0.83 0.29 0.35 -0.05 -0.44 -0.66 -1.19 -1.24 -1.30 -0.53 0.52

2001 .60 .29 0.45 -0.31 -0.30 -0.47 -1.31 -0.77 -1.37 -1.37 -1.26 -0.93

2002** 0.27 -0.64 -0.43 -0.32 -0.63 -0.35 -0.31 0.60 0.43 0.42 1.51 2.10

2003** 2.09 1.75 1.51 1.18 0.89 0.68 0.96 0.88 0.01 0.83 0.52 0.33

2004** 0.43 0.48 0.61 0.57 0.88 0.04 0.44 0.85 0.75 -0.11 -0.63 -0.17

2005** 0.44 0.81 1.36 1.03 1.86 1.17 0.66 0.25 -0.46 -1.32 -1.50 0.20

2006** 1.03 0.66 0.05 0.40 0.48 1.04 0.35 -0.65 -0.94 -0.05 -0.22 0.14

2007** 0.01 0.04 -0.36 0.16 -0.10 0.09 0.78 0.50 -0.36 -1.45 -1.08 -0.58

2008** -1.00 -0.77 -0.71 -1.52 -1.37 -1.34 -1.67 -1.70 -1.55 -1.76 -1.25 -0.87

2009** -1.40 -1.55 -1.59 -1.65 -0.88 -0.31 -0.53 0.09 0.52 0.27 -0.40 0.08

2010** 0.83 0.82 0.44 0.78 0.62 -0.22

I'm still awaiting the major flip into PDO negative and you can see from the above the impact of those record AO's this past Dec/Jan/Feb.........

Hold onto your dream by all means but keep a little bit of you based in reality Y.S. eh?

EDIT: As you know PDO-ve has been being 'called ' since 2000 (certainly for those who used the old 'Beeb' board will remember this) but NOAA didn't 'call it until 08' (as it was 'expected and the figures had become -ve) but then it 'milded out' again.

It seems the same folk who hammered NASA about the timing/length of the current solar min are using the same 'goalpost manoeuvres' as they criticised NASA for using with there 'updates'!!!

PDO is altering (milding out) so the type of PDO-ve folk are calling for does not exist any more......I blame the Arctic Amplification for this (since it was first measured/confirmed back in the early noughties........just when PDO-ve failed to arrive!!!).

If I am correct we should be deep into the PDO-ve 'phase' but most of this has been 'milded out' with only the big dips showing as negatives. As such we could already be 1/2 way through the current PDO-ve phase and all we have seen is the decimation of the ice volumes and perennial pack. Why should I expect anything different as we enter the declining phase of PDO-ve and see A.A. ramp up and drive 'extreme A.O. swings over winter?

Edited July 21, 2010 by Gray-Wolf

[stewfox]

1 ? snip

I notice we are not allowed a Antartica thread

However In a recent report the word RECORD was used eleven times in describing the Arctic sea ice loss. Whereas the June record HIGH in the Antarctic got not one mention. Instead there was a lecture about greenhouse gasses, models and unsubstantiated information about the ozone layer, all unsubstantiated.

I would have thought post the AGW fallout we would expect some reason debate , it appears not.

You won’t see any mention of Antartica sea ice being the third highest in the satellite records in the media.

Please to see CryoSat-2 Returns First Data

http://www.redorbit....rns_first_data/

I hope this

--------------

Around 150 scientists from about 40 research institutes now have access to the data. As part of the calibration and validation procedure, it is their job to help ensure these measurements meet the mission's exacting standards before the data are released to the wider scientific community later this year.

--------------

Doesnt take too long any hold ups will just feed the conspiracy camp

I can see it now ice volumes 30% greater then expected , data needs 'tweaking' says scientists'

Edited July 21, 2010 by stewfox

[Gray-Wolf]

Nah stew, there's a 'Trick' for that!!!

[bush]

If I am correct we should be deep into the PDO-ve 'phase' but most of this has been 'milded out'

GW if you have a look at http://jisao.washington.edu/pdo/ you will notice that the cyle does not remain consistently cold but can even move into a warm state for short periods.

[Gray-Wolf]

I do understand this bush but if you look at the 2 notable PDO-ve's (since 1900) you'll see a good run of -ves for sustained periods. My concern is the A.A.'s impacts on the AO Esp. if we get a lot of dark water exposed from here on in (as it's looking increasingly likely to be!).

You explain our understanding of an another large A.A.'s impact on the A.O. and it's teleconnection to the PDO-ve and I'll show mine!

[noggin]

What silence?

I'm here, I replied. Who else is here to reply? Have a bit of patience...

We posted at the same time. Don't be such a wet blanket.....

[sunny starry skies]

Difficult to read Polyakov's crucial slide where he suggests a 'peak', interesting if true, however I'd be awfully cautious about declaring a peak only two years after the event. His second-last slide is disingenuous if he spoke to it about a post-2007 cooling, as the data on the slide ends in 2002. But all that said, it would be good news if he's right. However, as Dev said, the physics is not in his favour, and are Atlantic SST anomalies not high at the moment - surely they'll feed more warm water into the Arctic, similar to the pulse post-1990?

G-W, I think you're right about the nature of the PDO and other cyclicities in ocean temps. It seems that we're well into the latest PDO -ve phase now, but it's well worth noting that the SST anomalies that are used to calculate the PDO are higher now than at any time during the previous positive phase! Specifically, the North Pacific has been warmer than in the last PDO positive phase since 1996, during which time we've been led to believe in a PDO negative phase for much of the time. See the graph in the link below:

http://bobtisdale.blogspot.com/2009/04/misunderstandings-about-pdo-revised.html

PDO: index relating to the spatial pattern of North Pacific temperatures. It is not remotely related to total heat gained or lost by the North Pacific. [if I have referred to it before as detrended temperature anomalies, it isn't that either as I have learned, and as Bob Tisdale explains above]. So if you hope that -ve PDO means global cooling, you're hoping wrong.

AMO: is a detrended temperature anomaly.

Maybe this is more relevant on the ocean page, but the clear observation is that absolute overall ocean temperatures are rising. Oscillations about that rising trend don't mask the fact that the trend is a rising one, and that the oscillations favourable for more Arctic sea ice occur at higher temperatures (therefore less favourable for sea ice) than they did during previous manifestations of those oscillations.

Interesting NSIDC post G-W!

sss