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Those maps are difficult to understand. Melt pond fraction is reported only for very specific locations, including a strange place in the middle of the Atlantic

Rob Dekker

Thank you Neven, for a well thought out, balanced overview of the situation in the Arctic at this point.

I appreciate David Schröder's team melting pond assessment this year

There is no doubt that melting ponds greatly affect the melting season locally, and thus his data is important and very well appreciated.

Did you obtain any information on how David Schröder's team determines this info ?


NSIDC sea ice concentration has dropped substantially today. That will not be reflected in Cryosphere Today Area numbers until Wednesday when it will drop by a massive 340k.

The first sign of this was an explosion of melt area in today's ADS-NIPR Jaxa thickness/melting maps (https://ads.nipr.ac.jp/vishop/vishop-monitor.html). A sequence was posted at the forum (http://forum.arctic-sea-ice.net/index.php/topic,1112.msg54089.html#msg54089). This is also the place to look at tomorrows and the day after tomorrows CT numbers.

Since extent did "only" drop by about 75k, the compactness calculated from NSIDC concentration has taken a plunge as well and is now at similar levels as 2013 and 2014.

To stay there (at 2103/14 levels), let alone get into record territory area will have to keep falling in the next few days. Today has shown it is possible.


340K? Wow, that's massive. A quick look at my CT SIA spreadsheet shows a drop that big hasn't happened since 2008.

Kevin McKinney

Thanks again for a nice summary, Neven.

Another 'interesting' moment, I'd say--hard to predict what turn will happen next, especially with that prospective 340k Wipneus is talking about.

Susan Anderson

Dumb question time for me. I had noticed that the spectacular early start for extent and area was returning to earlier (still lower) norms, so how does the above-mentioned concentration figure into that (not too technical, please, if possible).

Meanwhile, Wipneus's earlier link needs to be edited to remove ")." or use this, stolen/done:

Chris Reynolds


It's a melt pond model augmentation to CICE which is driven by NCEP/NCAR atmospheric forcing.


Those are anomaly plots, or difference from the long term mean. Where they are white the difference from the long term mean is too small to display.


Thanks, Susan. Links fixed.

I had noticed that the spectacular early start for extent and area was returning to earlier (still lower) norms, so how does the above-mentioned concentration figure into that (not too technical, please, if possible).

Are you referring to the low (and early) maximums? Compactness is usually high for most of the year, around 95%. It doesn't tell us much then. It's when the melting season gets going, and melt ponds start to form and/or the ice pack gets dispersed (open water between floes), that area will go down faster than extent, and the compactness percentage follows (see explanation in the post).

Is that what you mean?

Chris Reynolds


The arctic region is covered by a grid, you can see the NSIDC 25km grid by going to cryosphere today, the regions map there is a grid, each pixcel represents one grid box.

Satellite microwave brightness is used to work out the concentration of ice in each grid box. And concentration is given in a table of numbers, one for each box.

Wipneus uses this gridded data to work out area and extent. You know what they are I presume?

Basically, if concentration drops away from the ice edge within the pack area will drop. But unless concentration goes below 15% extent won't drop. In that case Neven's CAPIE index will fall, and we'd say that the pack becomes more dispersed. Where most of the loss of concentration is from the region around the ice edge both area and extent fall at the same rate. In such a situation Neven' CAPIE index would remain roughly level.

I use compactness, area divided by extent, that has been fairly average all June so far. this suggests that through June so far the loss of ice concentration within the pack has bee normal.

In years like 2007 & 2012, there was a lot of loss of concentration from within the pack, so by this time in June CAPIE (and compactness) were falling faster than normal.

Hope this helps, if not just ask.


I think as Wipneus' post indicates - a triple century on Wednesday - we do not possess information about all of the forces currently at work.

We are dealing with a moving target, and I'm not sure that assumptions based on a previous years events will translate accurately into what will transpire in 2015.

I suspect that Dr. Schröder's estimate is far, far to conservative. Based on the 2015 Maxima, it would require that the net melt would be less by nearly 1 million KM2 than has happened in the last 5 years.

Since 2007 every year has had more than 10 Million KM2 of melt; considering 2015's maximum was slightly over 14 million KM2, a 5 Million KM2 minimum demands less melt than has happened since 2006.

IF current weather conditions were on a par with 2013, I *might* think that possible; however, in the face of conditions which are highly unfavorable for retention of ice, I find that highly unlikely.

I'm not yet certain that we will reach a new minimum, but I am confident in spite of good Dr. Schröder's prediction, that we will pass 5 Million KM2 by a wide margin.


Modest re-statement;

SIA losses have been consistently 10M KM2 since 2006.

Looking at IJIS data, there have been sub 10M KM2 years, but none less than 9.5 M KM2 (2014); the average annual extent loss from 2007 forward is approximately 10M KM2.

Even considering this oversight on my part, the upshot of this is, Dr. Schröder is low by at least 500K KM2; and that is only if the melt season is on a par with 2014. So far, it shows no sign of cooperating with our desire to preserve the ice.

Rob Dekker

According to Wipneus' concentration maps :

the 'course' (25 km^2) NSIDC concentration dropped very quickly to normal levels, but the high resolution (3.125 km^2) concentration is still anomalously high.

What I make of that (Wipneus please correct me if I'm wrong) is that there is a lot of thin ice at the edges turning to slush rather quickly, but the interior of the pack is still quite "white" and resilient.

I think the jury is still out there on where 2015's minimum will end up.

Yvan Dutil

Andrew Slater projection have just collapsed in the last few days.


Susan Anderson

Thanks Neven and Chris Reynolds, that is kind and helpful as well. (Yes, I meant the very early maximums and subsequent deviation from previous years.) There are so many different weird things going on everywhere, it's hard to tolerate the general embrace of blindness, but getting ahead of ourselves doesn't help either.

And since I'm always boring on about these, here's a better link for the polar view of the water vapor animation (because you can slow it down):

I continue to be fascinated by earth's venting systems, in particular the way all that cyclonic activity in the Pacific is sending heat north, while at least some of Alaska continues ridiculously hot.

the 'course' (25 km^2) NSIDC concentration dropped very quickly to normal levels, but the high resolution (3.125 km^2) concentration is still anomalously high.

Yes and it is a bit of a puzzle. Compactness is depending on resolution, but melt ponds are small (I think) compared even with the 3km resolution. So in this case resolution should not matter. At the very least some response should be seen.
The SIC product differ in more aspects than resolution, the microwave bands and calculations (known as "algorithms") are all different. The NSIDC uses the NT (NASA Team) algorithm, that is known to underestimate concentration especially during melting conditions. More than other algorithms.
Melt ponds that deserve the name "pond" should affect all algorithms equally, the microwave bands used cannot distinguish ponds from open water.
Therefore I think that the melt effect we are seeing is not melt ponding yet but rather the change from dry ice to wet ice, dry snow to wet snow, ice covered with snow to bare ice.

So will this melting effect continue? Will ponds form and affect the other ice algorithm as well?

FYI, I posted this on the forum today:

From today's NSIDC sea ice concentration data update, I calculate the CT-area updates of the coming few day's:

Mon 9.106157
Tue -119.6 8.986600
Wed -340.2 8.646372
Thu -71.6 8.574772

After Wednesday the drop on Thursday will be much smaller. Regarding the small extent uptick of (NSIDC calculation +4k6), the melting effect is still very much active.

Colorado Bob

Acidification takes toll on Beaufort Sea; threats loom in Chukchi and Bering

With their low temperatures that hold onto the carbon dioxide absorbed from the atmosphere, their shallow depths, their rich supply of marine life and carbon dioxide carried in by currents from elsewhere in the world, and their increasing supply of runoff from melting glaciers and glacier-fed rivers, Alaska’s ocean waters are known to be highly vulnerable to acidification.

Now comes a finding that the Beaufort Sea has already crossed an ominous ocean acidification threshold, and the Chukchi Sea and Bering Sea will follow in the foreseeable future, with water conditions that would be corrosive enough to cause many marine species to struggle. ..................................

The Beaufort Sea has already reached a state where its surface waters, on average throughout the year, hold too little calcium to fully support shell-building organisms, according to the new findings.

Based on measurements made during research cruises in 2011 and 2012 aboard the U.S. Coast Guard icebreaker Healy, that threshold was crossed in 2001, the scientists found.

Alaska Dispatch News


Lots of new melt ponds over the last few days

Esp for buoys 10,11 and 12


And like Susan I've been watching the huge swirls in the Pacific sending warm air north and cold air out seemingly pushed out the other side ( so to speak :)

I think melting will be pretty significant this year, maybe not a record but worryingly close.


Kate wrote:

buoys 10,11 and 12

Me thinks it could be handy to have them all into one and the same page. Feel free to download the file by right clicking onto the bold ecc... ecc...

- Obuoys 3 and 13 are still “grounded”, but still, its good to have them pronti.

- As a bonus both the cams 1 & 2 from Washington.edu

Hank Roberts

Question -- sanity check on this?

The story is, vaguely, attributed to Neven's Sea Ice site, but I haven't found the source here yet.


See comment on this same post,(Wipneus)

Sources are there.
However the story is written in a pretty sensationalist way. He forgets to mention that such drop is not only ice gone but also ponds fooling the satellite sensor and making believe it is open water and ice is gone.
No, a piece of ice cap of the size of New Mexico did not disappear overnight.
Plus, there have been a few days of slow area decline as well, before and after that monster drop


I was talking about Robert Scribbler's story, not Wipneus' :)


Navigante wrote:

sensationalist way.

To put it mildly. I rather would say it's misleading as the published Cryosphere (not Cyrosphere!) chart shows SIE, not Sea Ice Concentration what the 340.000 Square kilometer are about - so it has nothing to do with Neven's ''centuries''.
And that it solely is about concentration can easely be monitered at the UNI-Bremen maps
from yesterday and the days before.
Bottom line, we can miss that kind of input as much as Cincinattus' contributions.

Incidentally, yesterday ADS-NIPR showed a drop of only 20 square km in extent.


Confirmation,today, for the 19th of Juin ADS-NIPR states only a minus of 14 square km in extent, in respect to the 18th.
Whereas UNI-Bremen shows a massive drop in concentration.

Me thinks it's a phenomena we haven't seen hitherto ...


Right now there is massive melt ponding and significant open water over quite an area. Checking the Barrow website shows temperatures at 10C and checking the landfast monitoring station


shows the same plus the fact that the shallow land fast water is now at around 0C.

So it's not going to be long as ice.

As ever, it will depend on the weather and the insolation it provides....

That; is yet to be seen.

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