By Steve Goddard
August 16, 2010 offered a great opportunity to put all the Arctic data together in a coherent picture. DMI showed a large drop in extent.
http://ocean.dmi.dk/arctic/icecover.uk.php
You can see the drop between August 15 and August 16 clearly in red in the modified NSIDC map below.
So what happened? Did 300,000 km2 of ice suddenly melt?
Not exactly. There were very strong winds pushing the ice in the Beaufort and Chukchi Seas towards the pole on August 15. This compacted the ice, reducing extent while increasing the average thickness.
You can see the August 15 movement of ice in Beaufort Sea in the satellite blink map below. Note how the ice edge is tightening up and compacting.
Will this continue? Probably not. The weather forecast calls for a return to colder and calmer weather in a couple of days. Look for the DMI graph to flatten out by the weekend.
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Steve,
I don’t know but it looks like some of that multi-year ice north of the Beaufort, Chukchi and East Siberian seas on this map
http://www.treehugger.com/files/2010/08/multi-year-arctic-sea-ice-continues-declines.php
is going bye bye,
Cryosphere is showing some of that as open water, maybe it drifted of somewhere.
I thought the biggest movement was off Franz Josef Land, where ice which has been crowding those islands, suddenly has receded 100 miles to the north. All happened in 1-2 days. Warm ocean currents both pushing back the ice and melting the edge into a straight edge, is my impression.
Jimash said at 10:38 am
….That certain weather is climate while other weather does not count.
and stevengoddard said at 10:44 am
Jimash
Hot weather is climate. Cold weather is weather. El Nino is climate. La Nina is weather.
No, no, no students. You’ve still have not learned your lessons. Now repeat after me; Weather can NOT affect Climate even though Climate is a summary of Weather, but Climate DOES affect Weather even though Climate is a summary of Weather. Got that? Nino, Nina, hot, cold or not. It’s how the energy flows.
Energy in, energy out,
Energy moving all about.
In the ocean, and atmosphere,
CO2 is the thing to fear.
Weather here is not forever,
Climate there is not much better.
More CO2 the culprit be,
As any scientist can see.
Though the weather it changes not,
It makes the climate oh so hot?
It makes no sense you say to me,
And though no expert, I agree.
So here we are for data max,
WUWT, for all the facts.
In 2009 at least the 15 % concentration was quite spread, and dispersion plus melting could cause quite a drop in extent well into Sept. With cold temperatures and compacted ice the minimum is likely to be way early this year. I’ll go with the 5.5. Murray
stevengoddard says:
August 18, 2010 at 10:38 am
R. Gates
You congratulated me on July 1 for calling the “dropping like a rock” flattening – to the day. Remember?
______
I congratulated you on the calling the “turn to the right” or something to that effect, which was a great call, and of course within a week it made a hard turn to back to the left (or down) and has continued down ever since. I wouldn’t call this whole epsisode a “flattening” as the sea ice extent continued to drop afterward. Flattening would imply—flat, I would suppose. These little wiggles left or right though, during the heart of the melt season are really signs of divergence and compaction, as storm systems and high and low pressure centers move across the melting ice in the summer and are not signs that the actual rate of melting of the ice has slowed or accelerated (as you so often try to imply)– it’s simply being distibuted differently. One can even make the argument that a period of divergence might be followed by a period of even more rapid melt as that diverged ice has moved further south over warmer waters. But all of this guessing and speculating is the reason why CryoSat 2 data will be helpful, and measurement of actual sea ice volume will be most useful– especially if it has high enough spatial resolution to look at the open water in-between 15% concentrated ice that has diverged and count it as 0 volume as it should be counted.
stevengoddard says:
August 18, 2010 at 11:46 am
AndyW
Nothing wrong with the word “melt.” The problem is when people use the word “melt” to describe other processes.
_____
Indeed, melt is an actual change in the state of ice from solid to liquid. A slowdown in the melting should not be implied just because ice is diverging, nor should an accleration in melt be implied when the ice is compacting.
The actual melt rate in the Arctic during any season will be determined by the total energy available for melting, delivered by atmosphere, sun, and water, and how the ice is distributed so as to be in contact with one or more of those energy sources for the maximum period of time.
bob
On average, the Arctic loses and gains an equal amount of MYI per year. This year, barring some very weird weather, there will be more gain than loss.
Steve maybe this seems like a dumb question:
From your blink comparator, I can see that ice is moving around, as distinct pieces persist in the two pictures. But by eye, I can’t really tell by looking that one picture is more compacted than the other.
But I understand that you have the raw pixel data for these picures; and assuming that the pixel value is representative of how much light is being received by that pixel, and assuming that open water is basically a black body, so not contributing much to the pixel total, one might deduce that a simple integral of all of the pixels would be a pretty good measure of the total ice area; if one assumes that the compaction has not yet started piling ice on top of ice.
Now I see that one picture seems to have a small cloud intrusion up at the top; and maybe you can replace that area with a black hole in both pictures, with not too much loss.
Do you have a quick routine to simply sum all the pixel values for a single grand total ?
I realize that one is making a lot of assumptions as to obliquity (these are scanned images aren’t they; not whole frame photos ?)
But your contention that the ice is just blowing around looks fairly solid from those two pictures; it would be nice to know if the total light value for the whole damn picture is the same for both.
George
phil.
I think you may be confusing thin clouds with ice in the April 15 picture.
The soot won’t make much difference. Sunshine and temperatures are too low to have much of an effect on the surface of the ice.
Phil. said on August 18, 2010 at 12:21 pm
What steady flow between the Queen Elizabeth Islands and through the Nares Strait? The PIPS Ice Displacement Forecast has shown little movement around there. Match that up with the very high ice concentrations of up to 100%, and consider also the ice thicknesses, and one can see why very little ice would be leaving from around there. It’s too compact and thick to move much at all.
stevengoddard says:
“Loss of ice extent this time of year is primarily due to compaction.”
_____
Steve, you have no proof of this, and it is likely is incorrect. We don’t always get compaction of the ice in the last few weeks of August, and yet the sea ice extent continues to decline in these final weeks of the melt season year after year. Please explain why that could be if it happens in years even when there is not compaction?
It’s because extent loss this time of year also comes from the residual heat in the water that is responsible for most of the melting this late in the summer. Hence the reason that the DMI temps, north of 80 degrees, even if they are accurate, are of little consequence to the melt. The final melt is “already in the cards” so to speak, as it will largely be determined by the amount of heat available in the open waters.
Bottom line, the loss of extent this time of year can be from both compaction and melting, and there is no proof that this year most of it is coming from compaction. A lot of ice has drifted out of the Arctic Basin into open waters further south and is melting in the continued warmer waters there, though there may also be some compaction going on as well. This all goes back to my criticism of some AGW skeptics, who like to credit “compaction” or “wind” being the cause of a speed up or acceleration of the extent drops, or DMI temps falling to be a reason the melt is supposed to be slowing, but it never seems to be heat delivered to the ice from sunlight, atmosphere, or water causing the melting or extent drops.
stevengoddard says:
August 18, 2010 at 1:21 pm
phil.
I think you may be confusing thin clouds with ice in the April 15 picture.
No, take a look at the companion 3-6-7 images, definitely ice not clouds.
R. Gates
You can see with 100% certainty from the blank map, that the loss in ice extent is due primarily to compaction.
George E. Smith
The ice edge is moving radially inwards towards the pole, so by definition it is becoming more concentrated.
The software is about 5,000,000 lines of code and has a GUI.
kadaka (KD Knoebel) says:
August 18, 2010 at 1:27 pm
Phil. said on August 18, 2010 at 12:21 pm
stevengoddard says:
August 18, 2010 at 11:48 am
bob
The only thing which could prevent an increase in MYI (2+ year old ice) would be if a lot of ice blows out the Fram Strait this winter.
And the steady flow of MYI between the QE Islands and through the Nares strait which is happening as we speak. Which is the thickest (oldest) seaice in the Arctic too.
What steady flow between the Queen Elizabeth Islands and through the Nares Strait? The PIPS Ice Displacement Forecast has shown little movement around there. Match that up with the very high ice concentrations of up to 100%, and consider also the ice thicknesses, and one can see why very little ice would be leaving from around there. It’s too compact and thick to move much at all.
Not so the Canadian Ice service and MODIS confirm what I said:
http://ice-glaces.ec.gc.ca/prods/FECN14CWIS/20100818000000_FECN14CWIS_0005142759.txt
http://rapidfire.sci.gsfc.nasa.gov/subsets/?mosaic=Arctic.2010229.terra.1km
From: R. Gates on August 18, 2010 at 1:39 pm
http://polar.ncep.noaa.gov/sst/ophi/color_sst_NPS_ophi0.png
That’s good to know, since where the ice now is the Sea Surface Temperature is practically everywhere running -1.5°C and colder, with the SST otherwise and around the ice running 0 to -1.5°C, thus there sure doesn’t look to be much heat available to melt that mostly freshwater sea ice. And if it stays nice and compacted, it’ll be more resistant to melt than if it was spread out at low concentrations. The rate of loss of extent should soon slow considerably.
Been following this Ice thing since 07 & have been rooting on the comeback as hard as I can But I have thought like R. Gates lately (Last 45 days)…The Ice has been melting due to warm SST & the Low DMI temps cannot faze it…in Fact the DMI is now shooting above Normal at a point where we need to halt this slide to below 09 where unfortuanetly I feel we are going to end up……SO…no 3 year gain ..BUT…I feel like there will be a rapid Ice gain & I Am Hoping & thinking that we will be in for a good year in 2011!
R. Gates, you are correct that heat gained in the ocean during summer continues to melt ice from below even as the air temperatures start to fall below freezing. It is not only wind and compaction that contribute to continued ice loss at this time of year.
AndyW says:
August 18, 2010 at 11:31 am
Thanks for your off topic rant but I don’t see how you have answered my point that “melt” is a dirty word in these parts.
——-
REPLY: You are most welcome. Sea ice melts & re-freezes, it’s the driver for the process that remains unproven. If you think that AGW is “proven” in any classical scientific manner, then I feel sorry for you.
I think the Arctic is doing just fine BTW. With the ongoing solar minimum, we are likely to have a nice, frosty winter with further ice consolidation & thickening. No arctic sea ice death-spiral in the making from everything I’ve seen.
BTW, please explain this to me: http://www.rohlfamily.com/2010/01/snowy-durham-uk/
My Brit friends were sure praying for some “melt” last winter! Hope they don’t get this challenge again this winter, they really aren’t set up to handle it.
DMI Arctic 80N-90N temperature average in melt season for 2010 ended at 0,34 K – all time coldest since 1958:
http://hidethedecline.eu/media/ArcticGISS/DMIis2010.jpg
K.R. Frank
“”” stevengoddard says:
August 18, 2010 at 2:14 pm
George E. Smith
The ice edge is moving radially inwards towards the pole, so by definition it is becoming more concentrated.
The software is about 5,000,000 lines of code and has a GUI. “””
Steve,
Yes I can see that the ice edge IS moving polewards, so as you say it IS compacting. But my question really points to a different question. That compaction could result in simply reduction of the open water (inside the ice field); which ought to keep the actual “ice” area pretty much constant; or at some point, you could have the ice starting to pile up on itself, in which case the are of the ice woule continue to diminish; but the amount of ice wouldn’t.
So I was thinking that if pileup was not (yet) occurring), then the total light returned from the ice ought to remain the same; while the light returned from the diminishing open water isn’t much anyway so the total light from the whole ice conglomeration would be the same for the two pictures. Given the pixel data, it would seem one could grab a nice rectangle that appeared to be all ice from each picture (same general region), and omitting that cloud cover area, and simply total all the pixel numbers to get a total light value which ought to be a quite good representation of the actual ice area and show that it isn’t diminishing even theough the extent is.
But I don’t want to create something that is a lot of work to do.
George E. Smith
The reason I think that the ice is piling up is because PIPS shows a higher average thickness than it did a week ago.
R. Gates:
While cryostat2 _will_ be useful to determine Ice Mass more accurately, the data gathered won’t be useful without a sufficient baseline. cryostat2 will help to establish the baseline over the next few decades; only when a sufficiently long baseline is established will any conclusions about trends be useful. Trends derived from baseline data of less than two AMO/PDO cycles aren’t particularly predictive, IMO.
I don’t have a high confidence in trends derived from paleo data.
Julienne
But what is the primary cause of loss in extent this past week?