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Neven
the extent map from Cryosphere today has more melt ponds and open water than anything I remember seeing in the last 4 years.

Those colours on the CT sea ice concentration map do not necessarily correspond with melt ponds, Philiponfire. I think clouds have something to with that as well, fooling the sensor. If those colours would stay put for a couple of days, there might be something going on, but that are continuously appearing and disappearing from one day to the next.

I just looked at the weatherundergrond GFS model that projects two weeks in the future, and I don't see the return to conditions that led to the rapid July melt.

Indeed, Lord Soth. The AO might go negative, but that's mainly because of a few big highs moving on from Scandinavia and staying in place above Svalbard. With the (big) low on the other side, we now get ice transport form Greenland/CA towards the Laptev Sea.

This is already apparent on the DMI SLP map:

Those isobars between the big yellow and blue blots show the wind direction and thus ice displacement at the moment. If this keeps up for a few days we will start to see holes in the interior of the ice pack, I think. ECMWF is forecasting things to saty as they are now, with a big low and a big high opposite each other, but exactly in the wrong spots for big extent decreases.

On the other hand, I always say that the switching in weather patterns is causing the slowdowns. If things do stay like this for a week or so, we might see an interesting rate of decrease nevertheless. Those waters in the Laptev Sea aren't exactly cool.

But let's not write too much, otherwise I won't have enough material for the next SIE update. :-)

Neven

It can clearly be seen on the PIPS ice displacement map as well:

The ice is transported away from Fram Strait, towards Siberia.

Fascinating...

Artful Dodger

NSIDC News -- 14 July 2011

AMSR-E Sea Ice Drift Data Now Available from NSIDC

NSIDC has released a new sea ice data set, the AMSR-E/Aqua Daily L3 6.25 km Sea Ice Drift Polar Grids. This Level-3 gridded product includes sea ice speed and direction generated by applying the Goddard Space Flight Center (GSFC) wavelet transform algorithm to AMSR-E brightness temperatures. As this is a beta-level product, further development and updates to the algorithm are anticipated. Daily drift data are averaged over five-day intervals and are mapped to a polar stereographic grid at 6.25 km spatial resolution. Data are currently available from 01 June 2011 through the present.
Tzupancic1

A useful website for visualizing the extended forecast for the Northern Hemisphere is this NOAA site:

http://wxmaps.org/pix/hemi.fcst.html

I like it because you can click on "All Times" for 500 mb Geopotential Hieght Vorticity and get a single page where you simply scroll down to see the forecast for the whole week.

There is a lot of additional information for each day that you can see by selecting "All Fields" for an individual time point.

Neven

Thanks for those two links, guys.

Pete Dunkelberg

Thanks for those links, Lodger.
I seem to recall something else as well. Sea water keeps getting denser as it cools toward freezing (at nearly 2 kelvins below the freezing temperature of pure water). So the coldest water keeps sinking until there is enough of a stack of very cold water to slow the sinking enough for the upper water to freeze before it sinks.

On the other hand, if the Arctic surface waters became very fresh for some reason, say a collapsing ice sheet, the Arctic sea might freeze as fresh water does, leading to a much greater extent and a severe winter. I hope the chance of this is below .1.

Chris Biscan

where id the data located for Breman.

L. Hamilton

Chris, the Uni Bremen data are not public yet, though I hope they will become so. Their long-term calibration is not complete. The data at present are said to be valid for day-to-day but not historical comparisons, hence the current UB website's approach of just showing the recent years graphically.

One interesting aspect of the UB time series is that it extends back to 1972 (but with that caveat about not being calibrated). Another is that they have estimates for southern hemisphere ice extent as well.

I try to respect my promise not to publish their data, and the historical cautions, while still occasionally posting a cryptic note here when I see something interesting happen.

Artful Dodger

Hi Pete,

This is what I wrote about salinity on September 11, 2010.

Unless salinity goes below 30 psu, the Arctic does not freeze like a fresh-water lake.

Pete Dunkelberg

aha! Lodger that's the one. Thanks again.

Meanwhile back on the ice, this looks like a good time to study pure melting in place. What is known about the import of heat by ocean currents?

Artful Dodger

Well, there's SHEBA and NAME... and there's this little "Arctic Ocean Heat inflows" chart by Wieslaw Maslowski:

Yes, all those little TW's are terawatts. (a terawatt is equal to one trillion (10^12) watts.)

Chris Biscan

How much do clouds effect the ice sensors

Tzupancic1

As Rob Dekker commented above,

"Now, since 2011 has the same ice area at 2007, it seems reasonable to assume that the enhanced melt will occur again (ice albedo). However, if the transpolar drift does not crank up, then 2011 will have a hard time keeping track of the Aug/Sept decline of 2007.

On the other hand, if PIOMAS is even remotely correct, then ice volume (ice thickness) in 2011 is already more than 2.5 10^3 km3 smaller than it was in 2007, which makes the 2007 Aug/Sept loss of 0.8 10^3 km3 look insignificant.

I think 2011 is a test of various hypotheses and we are observing the data rolling off in real time.

Tzupancic1

"On the other hand, if PIOMAS is even remotely correct..."

Reardless of the weather.

This is the question that currently fascinates me. If the Arctic Sea Ice volume is so reduced, what are the implications?

Andrew Xnn

Implications of reduced volume?

First, that comparisons based on area and extent are fundamentally misleading. In other words, be careful comparing 2007 to 2011.

Second, that there has been no meaningful recovery of arctic sea ice.

Chris Biscan

60K prelim on Jaxa.

Rob Dekker

Chris wrote : How much do clouds effect the ice sensors ?

Not sure how much clouds affect the sensors, but clouds very much affect the melt rate. During July, the sun in the Arctic is still brutal. Clear sky melt rate for insolation alone can easily be 3-5 cm/day for already battered ice. But if the sun is blocked by clouds (having high albedo) ice melt rates will reduce significantly, down to a standstill for thick clouds.

Interestingly enough, at the end of July (July 28 if my calculations are right), the radiative balance of the atmosphere starts to turn negative. That means the atmosphere will loose more heat (to space) than it absorbs from solar irradiance. That means it will cool down. After that, at the surface, cloud cover and sensible heat transfer (warm air blowing in from lower lattitudes) will determine the melt rate and ultimately the point where melting ponds start to freeze over and melting halts.

So clouds (and weather in general) are very important in the Arctic.

If I have a chance, I'll post some results of the radiative balance and melt rate calculations for different surface and weather conditions, which will confirm that conclusion. Credit to Wipneus and others who helped me find the right tools.

Neven

Rob, if you want your efforts to be turned into a blog post, you know where to find me.

Rob Dekker

Thanks Neven. After all the great info I obtained from you and so many excellent posters here, I know that I owe you a blog post with what I've learned. My main problem is time... Don't have enough of it. And some tools to make graphs and pictures for a blog post.

Espen

Disturbing or may I say "Welcome to the USSA"

http://www.guardian.co.uk/world/2011/jul/28/arctic-scientist-polar-bear-oil

Neven

I have turned that Guardian article in a blog post.

My main problem is time... Don't have enough of it.

Tell me about it, Rob. In fact, I feel a bit guilty for not following your lead into this. Things like insolation and bottom/top melt rates are very interesting. Maybe we'll get around to it towards the end of the melting season.

Seke Rob

The "New Polynia" has returned... just noted it in the CT Arctic image North-East tip off Greenland

http://arctic.atmos.uiuc.edu/cryosphere/NEWIMAGES/arctic.seaice.color.000.png

Cstch it while you can.

michael sweet

It looks like a lead is opening up in Arctic Web Cam 1.

Philiponfire

it looks to me as though there is now a North West channel open for small craft as of Modis day 29th july.
I am referring to a route through Prince Regent inlet, Bellot strait, Franklin strait, Rae strait, Simpson strait and Coronation gulf.

nothing more than ice cubes on that route now.

Chris Biscan

Jaxa and UB have diverged themselves some.

So far the extent and area have slowed to a crawl.

I can't expect this to last given it is only July 30th but this a good sign.

R. Gates

I strongly suspect August 2011 will hold a dramatic surprise. Vast amounts of warmer than usual water with a little nudge from a negatively trending AO Index, and the race between 2007 and 2011 will be far more interesting than would appear as of July 30.

Neven

I agree that there is still a lot of potential for extent decrease, but things will have to start changing soon now if 2011 wants to remain record material.

I'm writing a new SIE update tonight and will elaborate some more.

Chris Biscan

I don't get why Jaxa and UB seem to be pretty far apart at this moment.

Philiponfire

If you look at JAXA and UB graphs side by side they never match exactly so there is no reason for them to be identical now.

Lord Soth

Things do look dismal at first glance, however we must remember that we are looking at extent, not area or volume.

Think of the arctic circle as a slice of toast. Think of the volume of ice as the peanut butter. Think of weather conditions as the knife.

The knife has been very effective in spreading the peanut butter over the toast in a nice thin layer.

The only problem with this analogy is that the peanut butter does not melt, like the thin ice.

When looking at the extent chart, one thing that stood out about 2007, was not the depth of the curve but the width. The ice melted early and recovered late. Right now 2011 looks alot more like 2007, more than any other year.

Right now 2011 is within 2% of 2007 for extent, practically tied for area, and way ahead for volume lost.

2007 not only had the lowest extent, but also known for extreme compaction.

August, 2007 showed 4 century breaks at the start of the month, but after the first week, it took 23 days to lose a million km, as it hit the wall on available compaction, and had to depend on in situ melt for it extent losses.

The big question is, can 2011 beat 2007, without the level of compaction that 2007 has.


crandles

I fully agree that 167k or 2.5% more extent than 2007 is only one measure and not all that significant. We should keep area and volume in mind as well as extent.

We have had an area century break putting area 44k below 2007 and below the gompertz fit of 4.383 for the next release. I suggest area is more important than extent.

Volume is the only measure that is way below 2007 but it is difficult to know how to rate the importance of this to this year minimum relative to area and extent measures.

So of extent, area and volume, 2 to 1 measures say 2011 is leading.

We can, however, also say is that these sizes of lead or lag have in the past been relatively unimportant compared to weather.

Maybe at some stage volume will become much more important than it has in the past but there doesn't yet seem much reason to think that will happen this year.

Chris Biscan

even with the slow melt days.


the ice has a large area that is about to compact/melt out.

look at those large areas of low low concentration.

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