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Rob Dekker

Paul Beckwith,
I'm as concerned (if not more) than you are about a collapse of Arctic sea ice on the very short term, and have the deepest respect for Prof. Wadhams to speak out about this risk.
My bet with William Connolley should attest to that
http://scienceblogs.com/stoat/2011/06/26/betting-on-sea-ice-10000/

Even though I respect your position, I have not seen any scientific publication from you that explains why the Arctic sea ice is declining as fast as it does, nor where it is going in the future. So, I don't think you have enough scientific evidence to validate an attitude of "I told you so", such as in this post :
http://econnexus.org/met-office-admit-our-climate-is-being-disrupted-by-the-warming-of-the-arctic/

And since there is not enough scientific evidence yet to even explain what is happening in the Arctic, nor where it is going nor how fast this may go, I feel that AMEG's standpoint that there is a 'solution' is inappropriate. From your web site :
http://www.ameg.me/

Fortunately there are several ways of cooling the Arctic. AMEG's preferred cooling method involves brightening marine clouds to cool surface currents flowing into the Arctic.

In fact, since we don't understand what is happening in the Arctic, statements like this by AMEG may are premature and since neither the economics nor the logistics nor the effectiveness of such ideas have been properly scientifically evaluated, this rhetoric will create false hope at best, and thus I feel they are counter productive at this point.

Neven

And there's the danger that it will be seized as an opportunity to continue BAU. I'm 100% against geo-engineering if it isn't preceded by systemic changes to the way we fit our economy into the ecology, if like little children we refuse to see there are limits to what we do.

BTW, one thing I know for sure, Rob, and that's that you're not going to lose that bet. :-)

Erimaassa.blogspot.com

Trying to make sense of the NW passage ice... The NW passage is under 100m deep on locations, shallower than Nares. the bathymetry forces any warmish water entering it to rise in these locations and clear it pretty fast once the sea ice on both ends have melted. The remaining shallow bit of the Parry Channel (Barrow Strait) near Resolute gets ice from the north and the currents here would then go to opposite directions. Anyway it's been the last place to clear in recent years. As to which water mass (the Pacific or the Atlantic goes into the Parry doesn't really much matter for the shallowness of the strait. AABW doesn't enter in Arctic Ocean anywhere AFAIK.

OldLeatherneck

Quoting Neven:

..... I'm 100% against geo-engineering if it isn't preceded by systemic changes to the way we fit our economy into the ecology......

I am equally opposed to geo-engineering for a number of reasons:

1. We currently have no ability to accurately model what is currently occurring in the Arctic and predict any reasonable timeline for a variety of climatological, meteorological, economical and societal impacts. What makes us think we can introduce another variable into an already complex system with any degree of confidence.
2. I greatly fear that the risks of unintended consequences of geo-engineering far outweigh any perceived benefits.
3. Any solution that does not curtail CO2 emissions is a non-starter. What is the benefit of slowing down the warming of the planet if we continue to kill the marine life in the oceans??

Artful Dodger

Furthermore, what makes you think the group of people that set out this plan 50 years ago to remove the Arctic ice cap will LET you restore it?

Remember, "Corporations are people my friend".

Cheers,
Lodger

OldLeatherneck

Quoting Lodger

Remember, "Corporations are people my friend".

Not only are they "people", they are such caring friends. It's so nice to curl up in bed with friends like Exxon-Mobil and Walmart, while they read you "Fairy Tales" as you drift of to sleep!!

Jim Hunt

IARC-JAXA extent is now down to 13,252,656 km2. The lowest for April 16th since 2007, which was 12,970,313 km2.

Jim Hunt

I note Rob has linked to one of my own blog posts on recent events in the Far North. Perhaps I should restate my own views on "geo-engineering"?

To be brief, I figure both economists and geo-engineers don't have the proverbial snowball's chance in hell of successfully controlling a complex system that includes long time delays. As Rob perhaps implies, if you can't even model what's actually going on in the real world, how can you possibly expect to be able to control it?

A-Team

Lieber Wipneus, could you please add a few explanatory details as to what you have plotted on concentration vs thickness? I'm not quite understanding the use of individual symbol variation, how June lumps daily sea ice concentration, statistical definition of the blue line, where the individual 5 years are contributing, the sharp slanting line on the left and so on -- thanks!

https://sites.google.com/site/arctischepinguin/home/piomas/grf/pm_thick_conc_6_31-35.png

 photo wipneusPlot_zpsa205b94d.png

If I am following your thinking on "thinner ice in PIOMAS comes with lower concentrations", the lion's share of Piomas output is largely anticipatable from concentration. Since sea ice concentration is little more than Ascat radar, we might be better off just using radar directly (with one-time calibration from IceBridge, Piomass, embedded thermister trains, etc).

Then the simplest way to get accurate daily ice thickness (and the forward trend line) at the most interesting time, winter and spring, is just to mask the Arctic basin, posterize (bin grayscales, possibly non-linearly for thinner multi-year ice slices) to the desired number of ice thickness classes, count pixels and plot.

Four years of Ascat data -- very manageable. However there is a big assumption here that has to be checked, namely that satellite, instrument and signal processing nitty-gritty leading to the posted daily Ascat image does not drift or get renormalized from day to day or year to year (like AVHRR).

And Ascat ice thickness is only the bridge to even better Jaxa ice thickness. There's much more information in 3 channels than 1, but increasing complexity of analysis comes with that. Beyond that, we actually have 5 combinable channels including the 89ghz. That gets us into optimal dimensional reduction, a well-trodden path in remote sensing.

Piomass grid cells seem to include all sorts of ice irrelevant to main basin evolution -- in the CAA channels, Hudson Bay, Fram, seas of northern Europe with wildly fluctuating conditions and so forth. I don't know if the single volume number excludes these, which are nothing but (loud) noise.

If not, more sensible masking of the radar would get at the 2013 melt issue much more sensitively. Not to mention far better ground resolution.

Finally, I should say Wayne is doing excellent work with his optical horizon monitoring -- he is getting actual local melt season onset, and quantitatively too.


Wipneus

A-Team:

PIOMAS gridded data comes as rectangle arrays, sized 360x120, when appropriate with added dimensions for month (12) and year (35).

One array is the average thickness, another the concentration per grid cell.
The plot is simply a scatter plot with x the thickness and y the concentration.

I chose for one month, as I suspect any relation between thickness and concentration may depend on the melt/freezing state of the ice. I choose for 5 years to make those boundaries nicely visible.

Those lines, sharp edge as you call the one on the left, are in the data. Some of them must be modeling artifacts.

Blue line is a smooth curve. Normally I use the default from the plotting library that I use (ggplot2) which is a Loess, smooth. This time I got a warning, that because of the large number of data points, a "gam" smooth was used. I have no experience with "gam" smooths, but forcing the method to "Loess" did give after twenty minutes of calculation a very similar plot. So I left it at that.

BTW, the dots are plotted with transparent color (so the ink won't blot the image) enabled. I do not know how the alpha channel survives until you have come to dissect the image.

A-Team

Thanks, Wipneus. Below i binned (posterized) Ascat radar every 4th day from 01 Jan 13 to 17 Apr 13 that was masked to the Arctic Ocean. The number of grayscale bins was taken as 10, which enough to put the multi-year ice into 3 categories of declining backscatter which were chosen to just capture the goat's head feature over the full range of dates.

I then entered the pixel count for each class into a spreadsheet. The fourth category is first and second year ice; the ice lying outside these groups were consolidated into a minor 5th category. Pixel counts are readily converted into sq km since the known area of the basin corresponds to 90,118 pixels for Ascat native resolution and the masking chosen.

Total multi-year ice, the sum of the first three categories, peaked in early February and has been declining about 1% per week ever since (last frame), modulo a bump around Apr 10th that may reflect lateral thinning as warming multi-year ice can spread out. The ice is notably more mobile than in past years.

It is running at about 83% of the multi-year ice of the same date in 2012. Years could also be lined up by date lag, ie when in 2012 (Feb, Mar?) did we have the same amount of multi-year ice?

Here I may revisit the masking to exclude more of the ice north of Svalbard or restrict to contiguous bin areas going north from the CAA. I have not yet varied bin number to check the sensitivity to that choice. Posterizing also needs to work consistently from 2010-2013, the years that Ascar data is available.

While pixel counts are nominally just areas, ice-penetrating radar is actually measuring something proportional to thickness. So once IceBridge or Piomass or on-the-ice data have provided the calibration, we discard them and just use Ascat for daily thickness and its trends (rather than some lagging indicator), at least for the rest of the spring.

 photo 2013AscatPoster_zps61830d0c.gif

 photo Ascat1213Comp_zps7b696301.jpg

Fairfax Climate Watch

I've just put the PIOMAS data set from Wipneus into a continuous time-series here:

http://www.fairfaxclimatewatch.com/blog/2013/04/arctic-sea-ice-concentration-hides-volume-plunge.html

...along with an array of Cryo Today images for April 22 side by side

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