Polar Ice Extent

[bush]

There are some really peculiar trends developing now with extent and area in the arctic. Could this be a reflection of cooler temperatures up north and a portent of a bad winter to come?. Check out the rather scary drop in the sea surface temperatures (specifically the rapid developement of La Nina and the cooling waters in the region affected by the PDO. The northern Atlantic is also cooling down now. Could be a serious problem for the northern hemisphere this coming winter.

[BornFromTheVoid]

There are some really peculiar trends developing now with extent and area in the arctic. Could this be a reflection of cooler temperatures up north and a portent of a bad winter to come?. Check out the rather scary drop in the sea surface temperatures (specifically the rapid developement of La Nina and the cooling waters in the region affected by the PDO. The northern Atlantic is also cooling down now. Could be a serious problem for the northern hemisphere this coming winter.

It is true that the Arctic is looking quite chilly this July, at leat compared to the last few, but that might not be enough to prevent a near record melt this summer. You only have to look at the modis images to see what a bad shape the Arctic is in http://rapidfire.sci.gsfc.nasa.gov/subsets/?mosaic=Arctic.

La Nina is developing very quickly this year and a clear negative PDO is visible but the negative PDO has failed to establish itself for any decent length of time for quite a while, even during the last -ve ENSO event.

The north Atlantic has cooled a little recently but the north Pacific has warmed a bit, look particularly at the central north Pacific and around Japan and the Kamchatka peninsula.

A postive would be that the Nares strait has become blocked recently and the cool 850s around the Arctic are fairly low, but these will need to keep going as they are for the next 6 weeks to prevent a very large melt IMO.

Welcome to Netweather by the way!

[Gray-Wolf]

I wouldn't say blocked DMS, look here;

http://neven1.typepad.com/.a/6a0133f03a1e37970b0134855c9016970c-pi

Running in reverse into the Lincoln sea???

Very Strange!

[parmenides3]

Useful reference tool:

http://www.ec.gc.ca/glaces-ice/default.asp?lang=En&n=4CE72415-1

or: http://www.ec.gc.ca/glaces-ice/4CE72415-E22F-4872-9C3E-8DC170BBFB3D/ar_breakup.gif

Context is everything.

Check out what is happening at the Fram Strait; if there is a lot of North-South flow there, then older ice can be flushed out of the Arctic and lost, which is bad.

P

Oh, and this... http://ice-glaces.ec.gc.ca/prods/WIS56DPTCT/20100705180000_WIS56DPTCT_0005069498.gif

Edited July 12, 2010 by parmenides3

[Gray-Wolf]

Useful reference tool:

http://www.ec.gc.ca/...En&n=4CE72415-1

or: http://www.ec.gc.ca/.../ar_breakup.gif

Context is everything.

Check out what is happening at the Fram Strait; if there is a lot of North-South flow there, then older ice can be flushed out of the Arctic and lost, which is bad.

P

Oh, and this... http://ice-glaces.ec..._0005069498.gif

Hi P3!, looks like minimal traffic out of Fram at the moment and you can see the lone arrow in Baffin showing the northerly movement there

Thanks for the links but I'm having difficulties applying them .They show breakup for Viscount Melville/McClure sound as sept 10th (or is that just ice min?) yet the ice there is well fragmented as I type?

With the current synoptics across the high arctic we appear to be in a holding pattern which will aide ice retention.Let's hope the waters are cold and we don't see too much ice melt in situ (as we are seeing on the 'pole cam'

If we could guarantee another 8 weeks of the same I'd be revising my 'min' guess up to 5 million!!!

[jethro]

Morning P3, long time no see around these parts, good to see you back.

[parmenides3]

Morning P3, long time no see around these parts, good to see you back.

Cheers J. Hi GW. Check out this forecast:

FECN16 CWIS 011800

THIRTY DAY ICE FORECASTS FOR THE EASTERN AND NORTHERN ARCTIC FOR JULY

ISSUED BY ENVIRONMENT CANADA ON 01 JULY 2010.

THE NEXT 30 DAY FORECAST WILL BE ISSUED ON 15 JULY 2010.

Air temperatures in the Eastern and Northern Arctic were above

normal during the second half of June, except in Committee Bay where they

were below normal. As a result, the retreat and melt of the ice along the

eastern margin of the pack ice in Davis Strait and Baffin Bay is

proceeding at a faster pace than normal and ice concentrations are

currently below normal in this area. The eastern margin of this pack ice

lies approximately 150 nautical miles further west than its normal

position at the end of June. Ice concentrations over most of Cumberland

Sound are also currently below normal. However, as a result of the Arctic

sea ice influx through Nares Strait, which did not consolidate this past

winter, and due to a recent period of easterly winds over Lancaster

Sound, ice concentrations in parts of northwestern Baffin Bay and in

Lancaster Sound are currently greater than normal. Old ice concentrations

in Nares Strait, Baffin Bay, the mouth of Lancaster Sound and in Davis

Strait are also greater than normal. Because of the above, the "open

drift or less" and the bergy water routes across northern Baffin Bay,

which were forecast to develop in mid-June, have not yet developed. The

"open drift or less" and bergy water routes to Thule, however, did

develop by the end of June (1 week later than forecast but still

approximately 3 weeks ahead of normal). Small openings in the sea ice

have developed in Eureka Sound and in Belcher Channel on the southwest

side of Norwegian Bay and ice melt in these areas is proceeding normally.

Forecast ice conditions for July 1st to July 15th.

Air temperatures for the first half of July are forecast to be

above normal over the Eastern and Northern Arctic and no significant

storms are forecast to affect the region during this period. As a result,

ice across the region is expected to continue melting at a greater rate

than normal. A brief period of moderate westerly winds associated with a

low pressure system crossing northern Ellesmere Island is forecast to

affect Jones Sound and Lancaster Sound on the 5th and 6th of July. This

event will cause some flushing of areas of fractured fast ice from Jones

Sound into northwest Baffin Bay and also cause flushing of the mobile

pack ice in Lancaster Sound towards Baffin Bay during this time. As a

result of this, as well as due to the continued influx of sea ice from

the Arctic Ocean through Nares Strait, ice concentrations in northwest

Baffin Bay are expected to remain greater than normal during the first

half of July, delaying the development of the bergy water route across

northern Baffin Bay by another 1 to 2 weeks. At the same time, these

winds will help fracture the fast ice in Jones Sound by mid-July, in

keeping with the forecast date for this event. Fracture of the fast ice

in Norwegian Bay, Pond Inlet, the northern half of Admiralty Inlet,

Wellington Channel and in McDougall Sound is still expected to occur near

mid-July, 2 to 3 weeks ahead of normal. In southern regions, ice

concentrations along the southern edge of the ice pack in Davis Strait

will continue to decrease and the remaining ice in Cumberland Sound will

flush out of the region. In Nares Strait, fast ice in adjacent bays and

fiords will continue to break off, adding to the old ice floes descending

from the Arctic Ocean and to the bergy water in the area.

Forecast ice conditions for July 15th to July 31st.

While air temperatures over southwestern and western Baffin Island,

the Gulf of Boothia and eastern Barrow Strait are forecast to remain

above normal during the period, air temperatures over the Northern

Arctic, Jones Sound, eastern Lancaster Sound and along eastern Baffin

Island are forecast to drop to below normal towards the end of July. This

may impact the fast ice fracture in Eureka Sound, the clearing of Pond

Inlet and the development of the "open drift or less" route to Cape Dyer,

all of which are forecast to occur by the end of the month. However,

due to the rapid melt and retreat of the ice that will take place during

the first half of July in these areas, fast ice fracturing and clearing

in these areas will likely still occur as forecast. The main ice pack in

east-central Baffin Bay will continue to shrink and by the end of the

period, the ice concentrations in that area will resemble conditions

normally seen in the first or second week of August.

END

GW, if my links aren't working, Google the Canadian Ice Service and navigate through the extensive products. Or try this link: http://www.ec.gc.ca/glaces-ice/default.asp?lang=En&n=D32C361E-1

[BornFromTheVoid]

Thanks for the links P3.

GW, I'm guessing those first 2 links for the Canadian archipelago are just showing the ice breakup date based on the 71-00 average?

Could definitely do with things remaining as they are for a while. It looks like high pressure will be building over Greenland in the coming days, could that accelerate ice loss through the Fram Strait?

[Gray-Wolf]

They are working P3 it's just that the Parry Channel,Viscount Melviliie Sound and McClure Straight are now fragmented. We've gone from this;

to this;

over the past 5 days and , to me, this looks like fragmented pack?

EDIT: Thanks DMS! that's probably it!

A return to the H..P. over Greenland (and northerlies through Fram and over us) will start the 'flush out' again but ,unlike previous years, there is little of the large ,older ice to flow out .We just have a slush puppy sea which may act like oil on water(?) and calm the surface down??

Without large floes (and their freeboard for the wind to blow on like a sail) how do we get the slush moveing?

Edited July 12, 2010 by Gray-Wolf

[parmenides3]

Thanks for the links P3.

GW, I'm guessing those first 2 links for the Canadian archipelago are just showing the ice breakup date based on the 71-00 average?

Could definitely do with things remaining as they are for a while. It looks like high pressure will be building over Greenland in the coming days, could that accelerate ice loss through the Fram Strait?

NADS: apparently, the Fram outflux is more a function of the Dipole Anomaly. This was supposed to produce Northerlies during July but current suggestions are that there more of an Easterly element than expected. The Russian sea ice service has good short-term current and wind flow forecast maps, if you're interested.

The perennial problem of the Arctic is its immense natural variability, which makes fools of forecasters. Its generally safer to make use of trends and tendencies over periods than look at synoptics, but the best you can do is gather the evidence on current and recent conditions from every possible source and then make inferences about what they might be indicating.

Current indication seem to be that the seasonal sea ice level is about three-four weeks ahead on long term average. Impossible to talk about records, really, but it's a surefire bet that the Summer low point will be very low, and the trend of long-term decline will be fortified, if not slightly worse than anticipated.

P

Are thos ehtr Rapidfire images, GW ? http://rapidfire.sci.gsfc.nasa.gov/

Edited July 12, 2010 by parmenides3

[Gray-Wolf]

I'd agree with all of that P3 but would add that we are in a 'different' Arctic today with a lot less of the old perennial to serve as a 'backstop' around the North of Greenland and North of the Archipelago. We are not seeing the ice 'piling up' in these areas (and thickening by the crush of ice ploughing into it from the North) but rather flowing around the old 'perennial maker' regions.

How we factor this into the trend of ice loss, and whether it makes a little or a large difference, is what I struggle with.

I do know that the loss of the pack's ability to 'thicken' over summer adds to the thin pack over winter and leads to the type of drop off we saw in ice extent through May/June. This , in turn, allows for a longer period of 'dark water' in the areas low in ice and so feeds the Arctic Amplification come re-freeze.

We have folk on here forecasting an early start to winter (and a cooling globe). We might see how, should the synoptics materialise, the Arctic Amplification impacts this 'coming cold' come Sept/Oct/Nov?

EDIT: Yes , sorry P3 ,images courtesy of MODIS AQUA and TERRA:oops:

Edited July 12, 2010 by Gray-Wolf

[CJWRC]

Hi ,

First post here .

Just have a look at this please: Latest Ice Extent + Area

It's a bit confusing , is that the ice refreezing?

Also , I think it is a bit propoganda like to post pictures of where ice has melted. Which in all likelyhood is nothing out of the ordinary for the time of year , maybe all those posts should state what is extrodinary melt and what is not!

[Gray-Wolf]

Hi CJWRC!

This is the confusion of the "15%+" measure of ice extent. If we have a solid pack with open waters around the coast then when that pack fragments ,and drifts into the open water (covering 15% or more of it) then the 'extent' figure goes up. We have had a recent wind reversal across sections of the Arctic Basin so there's a lot of jostling of the fragmented pack right now.The odds are that the new 'direction' of flow has enabled ice to drift into open ocean and this will increase the extent figure. This is ,of course, a fleeting thing as the ice flowing into these waters is placing itself in a strong melt environment.

As for the last two images I posted this is incredibly rare with only 07' having such access through the straight (and in 07' it took until late Aug/Early Sept for the channel to clear). If things continue as they are the channel will clear by the start of Aug! Remember the first passage through the NW Passage took 2 years (2 winter lay ups) and now it would take a few days to do the same!!!

As for the 'ice' do check out both the 'near real time images' and the Arctic Mosaic (go back a day to see the whole Arctic);

http://rapidfire.sci.gsfc.nasa.gov/

then you will know for yourself how the ice is doing!

Edited July 12, 2010 by Gray-Wolf

[parmenides3]

Hi ,

First post here .

Just have a look at this please: Latest Ice Extent + Area

It's a bit confusing , is that the ice refreezing?

Also , I think it is a bit propoganda like to post pictures of where ice has melted. Which in all likelyhood is nothing out of the ordinary for the time of year , maybe all those posts should state what is extrodinary melt and what is not!

Hi CJWRC & welcome. No, it's mostly the ice being shifted around. Sometimes, given the weather up there, there might some surface ice formed during the melt season, but generally, once it starts melting, it carries on melting till the end of the season (roughly, September). There are lots of things to know about arctic sea ice, so simple snapshots can be confusing.

I'm not sure how it can be propaganda-like to post pictures showing what is; this is simple observation of fact. What the image means, and how it is interpreted, can be subject to bias in the person doing the interpreting, but generally, if there's not much ice there, then it's not there. Is it propaganda-like to show a long-term trend? Surely, propaganda is manipulation of fact ( or disinformation, or straight-out lying) for political purposes. Do you believe that the images shown, or the graphics/facts, are inaccurate? If so, do you have a basis for this belief?

P

[CJWRC]

This is the confusion of the "15%+" measure of ice extent. If we have a solid pack with open waters around the coast then when that pack fragments ,and drifts into the open water (covering 15% or more of it) then the 'extent' figure goes up. We have had a recent wind reversal across sections of the Arctic Basin so there's a lot of jostling of the fragmented pack right now.The odds are that the new 'direction' of flow has enabled ice to drift into open ocean and this will increase the extent figure. This is ,of course, a fleeting thing as the ice flowing into these waters is placing itself in a strong melt environment.

Thanks GW,

But is this also true for earlier in the season when winds were the opposite , was the wind compacting the ice and hence totally exagerating the melt?

I'm not sure how it can be propaganda-like to post pictures showing what is; this is simple observation of fact. What the image means, and how it is interpreted, can be subject to bias in the person doing the interpreting, but generally, if there's not much ice there, then it's not there. Is it propaganda-like to show a long-term trend? Surely, propaganda is manipulation of fact ( or disinformation, or straight-out lying) for political purposes. Do you believe that the images shown, or the graphics/facts, are inaccurate? If so, do you have a basis for this belief?

Thanks , but I was just wondering was it along the same lines , as when the news shows pictures of ice melting , ok , but if its during the summer on the edge ice pack well then whats special about that? I was thinking along thos lines , you could go back to the ice age and see similar scenes fo melting ice. See what I mean?

[Gray-Wolf]

Once ,CJWRC, we had a lot of 'perennial' ice which was plenty thick and would slow down ice loss from Fram and Nares and would 'trap' single year ice which was driven into it further thickening this ice. Sadly this year we have so little ice that even whilst the wind has been driving it towards Greenland/Canadian Archipelago this has not occured and the small, thin ice fragments have flowed south (not even beaching on Greenland's north shore!!!) to melt.

Though new it was a predicted phase of the 'death spiral' and further compromises the packs ability to maintain.

I do believe that we have crossed a 'tipping point' and that we now have no way back (apart from another ice age!) to the pack that used to exist across the Arctic. I would not care to predict when the first 'seasonal' pack would emerge but even with the most conservative extension of the current trend it will not be long.

The past 2 summers have been 'average' summers yet we saw 2 of the lowest 3 ice extents ever recorded. This year we went into summer with even less ice volume (i.e. for the 'extent' we saw the ice must have been spread pretty thinly) so you'd expect another 'average summer' to bring about another top 4 low come Sept. Of course the trend in ice volume loss will also continue.........and on it goes.

If the Dipole ,that we saw in 07', does continue for the next 8 weeks then we will break the 07' record low as we have less ice and a 'similar' synoptic (seeing as some folk like to blame 07' on weather alone!!!) as in 07'.

At some point you will have to accept that most of all you read about the Arctic decline is accurate measurement/observation with no spin. Why would folk seek to deceive about something so important?

Edited July 12, 2010 by Gray-Wolf

[songster]

Thanks for the links but I'm having difficulties applying them .They show breakup for Viscount Melville/McClure sound as sept 10th (or is that just ice min?) yet the ice there is well fragmented as I type?

EDIT: I really should read the whole thread before replying :-)

Edited July 12, 2010 by songster

[CJWRC]

Once ,CJWRC, we had a lot of 'perennial' ice which was plenty thick and would slow down ice loss from Fram and Nares and would 'trap' single year ice which was driven into it further thickening this ice. Sadly this year we have so little ice that even whilst the wind has been driving it towards Greenland/Canadian Archipelago this has not occured and the small, thin ice fragments have flowed south (not even beaching on Greenland's north shore!!!) to melt.

Though new it was a predicted phase of the 'death spiral' and further compromises the packs ability to maintain.

I do believe that we have crossed a 'tipping point' and that we now have no way back (apart from another ice age!) to the pack that used to exist across the Arctic. I would not care to predict when the first 'seasonal' pack would emerge but even with the most conservative extension of the current trend it will not be long.

The past 2 summers have been 'average' summers yet we saw 2 of the lowest 3 ice extents ever recorded. This year we went into summer with even less ice volume (i.e. for the 'extent' we saw the ice must have been spread pretty thinly) so you'd expect another 'average summer' to bring about another top 4 low come Sept. Of course the trend in ice volume loss will also continue.........and on it goes.

If the Dipole ,that we saw in 07', does continue for the next 8 weeks then we will break the 07' record low as we have less ice and a 'similar' synoptic (seeing as some folk like to blame 07' on weather alone!!!) as in 07'.

At some point you will have to accept that most of all you read about the Arctic decline is accurate measurement/observation with no spin. Why would folk seek to deceive about something so important?

Right ok,

But can you awnser my question. You say that this slow in melt is due to a reversal in the wind direction. So is it also true that southerly winds compacted the ice , casuing the ice extent and area graphs to exagerate the ice melt?

What else could be the cause since temperatures have been below normal up there for ost of the summer?

And surely the ice was thicker this year than in 08 and 09? so that cant be the awnser.

[parmenides3]

Thanks GW,

But is this also true for earlier in the season when winds were the opposite , was the wind compacting the ice and hence totally exagerating the melt?

Thanks , but I was just wondering was it along the same lines , as when the news shows pictures of ice melting , ok , but if its during the summer on the edge ice pack well then whats special about that? I was thinking along thos lines , you could go back to the ice age and see similar scenes fo melting ice. See what I mean?

When TV shows glaciers calving during reports about climate change it is doing so for 'dramatic effect'. Lots of ice melts every year, lots of water freezes every year (in quantities which are hard to comprehend, they are so vast). The important thing to look for is the difference between the average amount which is recorded as coming and going, and the current situation; the anomaly. The anomaly can be positive or negative, meaning more or less ice than average is melting/freezing. A big anomaly (two or more standard deviations from the 'norm') is a cause for concern if it is part of a trend; in reality, the range of variability every year is so vast that one 'extreme' year may or may not carry a larger signal.

What is unusual about the Arctic sea ice is that there has been a consistent trend of decline for a long time now, that this trend appears to be accelerating, and that there hasn't been a positive anomaly in ice area or extent since 2003, which is unusual in itself. These are indicators that the pattern of things is changing. The pattern of things changing is, in other words, a 'climate change'.

What is worrying to a lot of scientists is that many of the world's natural systems exist in fine balances, which are vulnerable to even small changes. Long term, large scale changes are a source of concern for two main reasons; firstly, they will have a knock-on effect, wherein the disruption to one part of a system will have an impact on another, and secondly, that the process of change may have a 'quantum' element, ie, at certain 'tipping points', a change may become more or less permanent, or a trend of decline or growth becomes 'fixed' and irrecoverable. In such a case, it is clear that there will be substantial consequences, but how long they will take to manifest, and what they will mean for the infrastructure of human societies, is very unclear, and, if you don't like the idea of mass extinctions or population crises, somewhat alarming.

Try to ignore the 'scary' stuff the TV/papers show and say; this is not science and it is often barely even based on fact; worry about what the evidence and observations show; this is less spectacular but more important.

P

Right ok,

But can you awnser my question. You say that this slow in melt is due to a reversal in the wind direction. So is it also true that southerly winds compacted the ice , casuing the ice extent and area graphs to exagerate the ice melt?

What else could be the cause since temperatures have been below normal up there for ost of the summer?

And surely the ice was thicker this year than in 08 and 09? so that cant be the awnser.

Don't confuse the measurement of sea ice area with the rate of melting; they are not the same thing. We use such terms as shorthand, but what the data shows is sea ice area/extent, which can be seen and measured, to a degree. Sea ice depth has been measured occasionally over recent years but this is much harder to do for such a large area, so inferences have to be made from whatever measurements are taken.

Again, look at the pattern rather than the detail; it is the trend which matters, which is why the measurers work on the basis of five or seven day averages, or even longer ones; statistically, the accuracy of a longer pattern is more reliable than the accuracy of a subset.

P

[Gray-Wolf]

Don't forget P3 we are over 1/2 way to having Cryosat2 fully comissioned and the results so far have been above expectations (both for Antarctica and the 'rifting it's been showing whilst overflying 'Ross' and across the Arctic) so we will have basin wide ,week by week (day by day if useful) thickness measures. We also have the U.S. IceBridge missions over the years they don't have their own sat info for thickness/volume so we will have both sets of data.

CJWRC, they tell us that '1st year ice' (2 to3m thick) easily melts out in a season esp. if drifted into warmer waters so the majority of the ice across the Arctic is of a vulnerable thickness

so we just have to hope for favourable winds to keep the ice tight packed in the central arctic. That said we all await this years data on the flow through Bering into the basin as this warm water can work it's way into the central arctic areas

[CJWRC]

Don't confuse the measurement of sea ice area with the rate of melting; they are not the same thing. We use such terms as shorthand, but what the data shows is sea ice area/extent, which can be seen and measured, to a degree. Sea ice depth has been measured occasionally over recent years but this is much harder to do for such a large area, so inferences have to be made from whatever measurements are taken.

Again, look at the pattern rather than the detail; it is the trend which matters, which is why the measurers work on the basis of five or seven day averages, or even longer ones; statistically, the accuracy of a longer pattern is more reliable than the accuracy of a subset.

P

If that's the case then , ice area and extent can't be used to say that there was big ice melt this year , which there was , but you cant have it both ways.

[Gray-Wolf]

If that's the case then , ice area and extent can't be used to say that there was big ice melt this year , which there was , but you cant have it both ways.

I've been trying to tell folk to wait for the volume data these past 2 melt seasons but many have preferred to 'cock-a-doodle-do' about 'ice extent' being greater than the 07' melt even though the ice volume has declined to lower levels than 07' on both melt years (and will again this year).

Once we have the depth measurements as a standard then ice area and depth should form the backbone of any study into ice gain/loss in future so we will be spared that silliness:)

[quest4peace]

I've been trying to tell folk to wait for the volume data these past 2 melt seasons but many have preferred to 'cock-a-doodle-do' about 'ice extent' being greater than the 07' melt even though the ice volume has declined to lower levels than 07' on both melt years (and will again this year).

Once we have the depth measurements as a standard then ice area and depth should form the backbone of any study into ice gain/loss in future so we will be spared that silliness:)

Total Novice to all this but is there any significance to the fact the positive anomaly in the antarctic is the the same figure difference more or less as the arctic negative ice level? (Compared to the norm) If that makes sense

Cryosphere today.

Northern Hemisphere 1.4 million below 1979-2008

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.arctic.png

Southern Hemisphere 1.3 million above

http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.recent.antarctic.png

Edited July 12, 2010 by quest4peace

[kold weather]

Conditions look fairly zonal this summer thus far, though in Europe we've been lucky enough to mainly shielded away from the jets so far.

Still a huge amount of heat locked in the Atlantic and I am worried that this will add even more juice to the fire come September but we shall see.

[Gray-Wolf]

Total Novice to all this but is there any significance to the fact the positive anomaly in the antarctic is the the same figure difference more or less as the arctic negative ice level? (Compared to the norm) If that makes sense

Cryosphere today.

Northern Hemisphere 1.4 million below 1979-2008

http://arctic.atmos....cent.arctic.png

Southern Hemisphere 1.3 million above

http://arctic.atmos....t.antarctic.png

Not really Quest. Though many folk in the 'dinialsphere' like to see it this way both ends of the globe have very different properties. The southern polar region is a mountainous continent and the north is all at sea level.

Also be aware the the 'screen' used to map land and ice is now including all the areas of lost ice shelf, that used to be plotted as land , as ocean so large areas snuggled up against the coast are now part of the 'sea ice' extent. If you think of the size of the glacier snout that was rammed off it's glacier over the southern summer you can see how this works.you get an area the size of Belgium added to the sea ice area plus a berg ,the size of Belgium, now classed as sea ice. When you think of the size of the berg that calved of Ross a few years back (whose remnant piece knocked off the glacier snout!!!) then you can see there is a lot of 'instant ice' in the form of the collapsed shelf and 'instant area' that can then freeze to add to the 'extent' figure.

When I spoke with Bob Grumbine about how this works he assured me that the screen is regularly updated so the 'coast' is nearly always up to date (the glacier loss will have been updated by now etc.) and the extra area then available to freeze helps 'plump up the figures'.

When we then look at the research into the impacts of the man made ozone hole on the weather we see another reason why Antarctica has shown anoms over the past 15-20yrs.

If we can blame SSW events (Sudden Stratospheric Warming) on cold outbreaks up here imagine what impacts the continuous extra warming that the ozone bring to the Strat means down there!!! Recent papers have outlined how both the Droughts in SW Australia and the increased precipitation on Antarctic Peninsula, along with the increase in speed of the circumpolar wind /currents flowing around Antarctica (this wind/current has placed Antarctic in a position of splendid isolation as thus far has escaped the worst of the warming the rest of the planet has seen) are all manifestations from our ozone depletion. Once we 'heal' the ozone hole both the warm waters and air masses from the rest of the globe will flood into the continent (which is a worry) normalising things.

Edited July 13, 2010 by Gray-Wolf