Arctic Ice Discussion

[stewfox]

If we impact ice melt then even that paper merely reflects the way things used to occur.

ce area seems to be passing other min totals almost daily now and volume sits at the bottom of the pile.

As for the final figure? Not long to go to find that out too!

Any link to volume data ? I thought with the Satalite launch we would be seeing more info on that in this thread ?

[4wd]

Has the melt stopped?

I've been following cryosphere today for a while and the melt seemed to have bottomed out around 3 days ago and now we have a few gains popping up?

Unlikely for at least 3 weeks but the rate slows dramatically now as higher latitudes are starting to refreeze.

If you look at previous years there's often a few days with 'apparent' slight gains by now, but it will almost always keep edging down until September.

You can still get plumes of quite warm air heading north just as at our latitude September can sometimes bring late heat even though the sun strength is like March or April.

[BornFromTheVoid]

Has the melt stopped?

I've been following cryosphere today for a while and the melt seemed to have bottomed out around 3 days ago and now we have a few gains popping up?

You can use this to track the melt rate (in extent) http://www.ijis.iarc...extent/plot.csv

It can be a little awkward with cryosphere today as they don't show previous days figures, but zooming in on the anomaly maps can help a bit. On CT It did slow down and actually increased for 2 days before having a large drop on the 13th, and a smaller drop yesterday.

[4wd]

By the time we hit Sept I imagine a number of folk pleading 'mitigating circumstances' regarding their personal predictions for ice min and a few claiming that those closest to the min figure have 'got their wish'..........

Right.... and what have you predicted every year since 2007?

And what actually happened?

Even Serreze has toned down his death spiral claims putting back the ice free summer another decade (2008 he said originally for ice free north pole but that was a 'mis-quote' when 2008 rebounded signicantly)

I think most guessed it would end up similar to the last year or two, and it will.

There is some evidence of more older ice being retained again.

By definition you can't regain 3 year old plus in one or two years.

The difference this year is currents and winds have not pushed it out - even though it seems to have been a bit warmer than last summer or two.

This looks like weather doesn't it - i.e. not climate change death spiral.

Just as 2007 was weather - as NOAA and more said at the time in their analysis.

[NorthNorfolkWeather]

BFTV, can you point me to where the predictions of the members for this season are? Been an interesting melt season, full of contradictions

[BornFromTheVoid]

BFTV, can you point me to where the predictions of the members for this season are? Been an interesting melt season, full of contradictions

First page on this thread. Here's the current extent 5,588,281km²

[NorthNorfolkWeather]

First page on this thread. Here's the current extent 5,588,281km²

Thanks,

That'll teach me to check the first page :-)

I think my figure may be too low, but I'll be happy if it is

[Snow Leopard]

While reading through the Arctic Sea Ice and Analysis page on NSIDC I came across this paragraph:

Conditions in context

Arctic sea ice loss slowed down in late July through early August; then over the past week, the rate of ice loss sped up. At present there is more ice than at the same time in 2007, which saw the record minimum September extent.

Data from the Advanced Microwave Scanning Radiometer – Earth Observing System (AMSR-E) sensor, processed by the University of Bremen, show ice tracking near 2007 levels. The AMSR-E instrument can detect small but widespread areas of open water within the ice pack in the Beaufort and East Siberian seas, because of its resolution (6.25 kilometers or 3.88 miles). Normally, NSIDC uses data from the Defense Meteorological Satellite Program (DMSP) F17 Special Sensor Microwave Imager/Sounder (SSMIS). F17 provides a longer time series of data, but at a 25-kilometer (15.5-mile) resolution.

Does this mean that they are now using a satellite with a higher resolution and comparing the data with measurements taken from a satellite with a lower resolution. Surely that cannot be correct?

I have emailed the NSIDC asking the same but have not had a response yet.

[BornFromTheVoid]

While reading through the Arctic Sea Ice and Analysis page on NSIDC I came across this paragraph:

Conditions in context

Arctic sea ice loss slowed down in late July through early August; then over the past week, the rate of ice loss sped up. At present there is more ice than at the same time in 2007, which saw the record minimum September extent.

Data from the Advanced Microwave Scanning Radiometer – Earth Observing System (AMSR-E) sensor, processed by the University of Bremen, show ice tracking near 2007 levels. The AMSR-E instrument can detect small but widespread areas of open water within the ice pack in the Beaufort and East Siberian seas, because of its resolution (6.25 kilometers or 3.88 miles). Normally, NSIDC uses data from the Defense Meteorological Satellite Program (DMSP) F17 Special Sensor Microwave Imager/Sounder (SSMIS). F17 provides a longer time series of data, but at a 25-kilometer (15.5-mile) resolution.

Does this mean that they are now using a satellite with a higher resolution and comparing the data with measurements taken from a satellite with a lower resolution. Surely that cannot be correct?

I have emailed the NSIDC asking the same but have not had a response yet.

To me it would seem that they're just making the point that the higher resolution satellites are indicating that we're closer to 2007, where as the lower resolution satellites say we're not that close, due to the pixels representing a larger area they're unable to "see" the small but widespread pockets of open water that hve spread through much of the Pacific and Russian side of the sea ice. I don't think they're indicating a change to different satellites, but that's just what I read from it...

[songster]

Yup. NSIDC (using lower-resolution SSM/I data) shows 2011 as a little above 2007. University of Bremen (using higher resolution AMSR-E data) shows 2011 and 2007 as neck and neck. Resolution isn't the only story though, since JAXA has 2011 slightly above 2007 even though they use AMSR-E. Some of the variation between groups is down to the algorithm they use to translate microwave brightness temperatures into ice concentration: how good they are at filtering out clouds, how well they pick up thinner ice, etc.

Interestingly, all three groups (so far as I'm aware from reading various sites) show 2011 as being neck and neck with 2007 (or even lower than 2007) for area, as distinct from extent. Thus, the remaining ice pack this year is at a lower average concentration than ever before in the satellite record, which suggests melting and/or wind-driven compaction may go on longer this year than most. My finger-in-air prediction is that 2011 will continue to lose ice faster than 2007 and catch up with it on NSIDC/JAXA sites by the end of the month. Thereafter, it's pretty much a toss-up as to whether we get a new record.

[BornFromTheVoid]

Sea ice extent is now at 5,548,906km²

That means we are now past the minima of 2004 and 2006 and this is where we stand with regard to other minima

2005 = +233,750km2

2007 = +1,294,375km2

2008 = +841,092km2

2009 = +299,062km2

2010 = +735,312km2

The melt rate for the last week has been 69,509km2/day, with the average since 1979 for August being 43,561km2/day.

We are just 307,500km2 off where 2007 was at this time of year. 2007 averaged a loss of 45,312km2/day from the 16th 'till months end, so we need to lose close to average to avoid catching up.

[Gray-Wolf]

Are we starting to see a hole in the centre of Kara? I know SST's are pretty hot there but if above 85N can melt out the ice it kinda looks like the ice there is very thin? There are some other areas that look like they are already on their last legs too so bottom melt may now keep melt rates pretty high (for the time of year).

[BornFromTheVoid]

Was working out the average daily increases/decrease in ice extent for each month of the year, and noticed that the average for September is a gain of nearly 14,000km2/day or over 400,000km2 for the month. That seemed kinda high to me so I checked back over the individual years and then the decades and got this:

The average monthly sea-ice extent increase in September

80s - 566,092.2km²

90s - 460,273.4km²

00s - 262,224.0km²

Going year by year, there is an awful lot of variance with some losing ice in Sept, while gaining over 1 million km2 in Sept the next year so general weather does play a big part in it. In no way definite proof of anything, and not a long enough time series to really know if this is particularly exceptional or not, but the trend is clear enough when the decades are averaged and it does seem to be another bit of evidence towards the idea that the Arctic ocean shedding it's "warmth" in early Autumn slows the ice growth a little. It may also points towards a shift in weather patterns resulting in conditions against ice growth in September.

After that I decide to work out the average date for the yearly minimum for each decade and got this

80s - 9th

90s - 12th

00s - 16th

It should be interesting to see how this pattern continues over the next few years

(I tried to do some correlation stuff between the extent change in Sept and the minimum date on open office, but 'tis quite confusing. Seemingly got a correlation coefficient of -0.68 over all the years, but that could be completely wrong. Doesn't matter I suppose, the link seems clear enough anyway!)

[The PIT]

Has the melt stopped?

I've been following cryosphere today for a while and the melt seemed to have bottomed out around 3 days ago and now we have a few gains popping up?

Doesn't seem to have yet looks like we're on for the second lowest ever though.

[Gray-Wolf]

We aeem to be at another odd juncture where ,in the past, ice spread would have slowed decrease. today ice spread just places vulnerable ice into warm water where it now melts (and leads to extent drops).

[BornFromTheVoid]

Cryosphere Today has updated and we're now at 3.228 million km2 http://arctic.atmos....cent.arctic.png

Only 3 years minima left to beat (2010,2008 and 2007) with only about 275,000km2 more ice loss needed to beat them. With all the fragmented ice around the Pacific and, increasingly, the Russian side of the Arctic, it say the chances are 50/50 that we'll have a new record sea ice minima in September.

[Gray-Wolf]

Cryosphere Today has updated and we're now at 3.228 million km2 http://arctic.atmos....cent.arctic.png

Only 3 years minima left to beat (2010,2008 and 2007) with only about 275,000km2 more ice loss needed to beat them. With all the fragmented ice around the Pacific and, increasingly, the Russian side of the Arctic, it say the chances are 50/50 that we'll have a new record sea ice minima in September.

My main concern, BFTV, is that folk will expect the same kind of 'finish' to the season as the JAXA plots show but , to me, we've had a big change since 07'. With a big thick spine of old ice plastered across the n.Of Greenland/C.A. and off into Beaufort there was no chance of it melted out by mid sept. The ice sloping off toward Fram seems pretty shattered (small floes) and not much of the old stuff left to fend off the warmer waters around them.

Even 80n is showing weakness and it is now the time that the thinner ice will melt out in the warm water. as for the Pacific side and off Siberia we know we have a lot of warm water and lots of 'slush Puppy ice' sat in it.

If we had no wind and drift then I'd still expect a lot of ice to give up the ghost over the next 3 weeks (balanced with new gains in the high north) so i can see us crawling towards the other mins. If weather comes into play we could see even more loss over those weeks (even the NW passage 'Deep Channel' is now warm enough to do away with ice drifting that way.

Bottom line is my 3.5 mill extent looks a lost cause now. Things would have to take a major turn from the worst to see the ice waste in that way but 07'? 07' is a maybe but with no 'perfect storm' involved (just another 'mixed year') how can we find ourselves in such a position.

The continuation of the recent low trend in final ice figures has to mean something to us all surely? Does it not say we are now into this level of ice no matter what the winter brings (extent wise...kinda like snow levels growing but still being gone earlier than ever?) summer will take 1/3 more extent that it used to (in the sat era).

Anyhoo's , I'm sure the same old same old will start to creep out of the woodwork as the next 3 weeks and try and point to some kind of 'recovery'.....

Let us not forget the 'perfect storm'. Let us try and imagine that year and how the modern ice pack will respond to such synoptics?

[Gray-Wolf]

Odd large drop (in extent) today? sat issues or a sign of how weak the ice is when hit with a windy L.P.?

[Gray-Wolf]

Another large drop (provis) today? Do we look to be heading back to the 07' plot?

[SteveB]

I am gutted we are still seeing large drops in ice volume. Really thought we had turned a corner, but alas the Artic is still in trouble.

Our only hope is if we see an early re-freeze.

Edited August 24, 2011 by SteveB

[BornFromTheVoid]

On the IJIS site, this is where we stand extent-wise as of today 5,121,563km2 and the average daily melt has been 61,000km2/day over the last week.

Since the last update I posted, we've passed the minima of 2005 and 2009.

That leaves us with just 2007 (+867,032km2), 2008 (+413,750km2) and 2010 (+307,969km2) left to pass.

On CT, the ice area has also dropped, to 3,161,000km2, which looks about 200,000km2 of lowest on record.

[Gray-Wolf]

I (think?) I've posted before that now the 'spine' of ice is gone the end of the season is now an 'unknown' as 're-freeze' will impact the high Arctic but a lot of ice , in warm water, will still melt out/compact (if synoptic's allow) as this occurs.

Any open water above 80N will not impact figures but the 'slush puppy ice' around the pacific/siberian side looks to be dissappearing in big amounts now?

Edited August 24, 2011 by jethro
removed inflammatory comments

[scotty_boy_winter]

Yeah the science doesn't lie, very worrying, we need a plan as a world

I (think?) I've posted before that now the 'spine' of ice is gone the end of the season is now an 'unknown' as 're-freeze' will impact the high Arctic but a lot of ice , in warm water, will still melt out/compact (if synoptic's allow) as this occurs.

Any open water above 80N will not impact figures but the 'slush puppy ice' around the pacific/siberian side looks to be dissappearing in big amounts now?

[Alan Robinson]

we need a plan as a world

I doubt you'll see one in your lifetime.

[jethro]

Yeah the science doesn't lie, very worrying, we need a plan as a world

Why? What do you intend to plan for?