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Messages - nukefix

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I'd be interested in seeing the study and whether they have sufficient statistics over several El Nino/La Nina events to claim causality.

What is the scientific basis for claiming that La Nina directly affects ice stream dynamics in the Amundsen sector?

The attached figure showing the average snowfall accumulation across Antarctica from 1955 to 2005.  This data clearly indicates..
What data is that? RACMO2 or similar?

Arctic sea ice / Re: Piomas vs. CryoSat
« on: November 28, 2013, 05:34:31 PM »
I wonder if it would not have been wiser to build in a laser altimeter instead of this radar, which measures the height of a plane somewhere within the snow layer, as I read somewhere.
So absolute values from CryoSat2 have to be taken with great care , it seems to me.
Lasers work well until they fail, which has been a big problem with IceSat. The big benefit of a radar altimeter is that it does not require cloud-free conditions..

I'm looking fonrward to Sentinel-1a SAR-satellite that will be launched in 2014 - with it monthly tracking of the calving fronts in Greenland will be possible in all weather conditions + the data will available to anyone.

Antarctica / Re: Antarctic Tectonics
« on: September 16, 2013, 03:02:37 PM »
I've been told that models of the lithosphere will improve a lot within a decade as some of the newer GPS-series will become long enough.

You're probably right on the wave-backscatter. If so, I'm puzzled why the ocean NE of Frantsa Yosefa is almost black. It should be rough, too, given the winds from the SW.
one logical conclusion could be that it's covered by a thin layer of new ice that is preventing wave-formation. Either that or it's almost dead calm water due to low winds.

OK here's ASCAT for today, enhanced, mid-tones suppressed. Showing some important aspects of ice-quality. Probably not easy comparable to other years FI because water vapour content gives very different refraction of the signal.
Thanks! The differences in backscatter are caused by liquid water content (wet/dry snow) and surface roughness, not changes in water vapor (C-band intensity is almost immune to atmospheric water vapor).

ps. where do you get the data from?

Arctic sea ice / Re: HELP! Are Ob Gulf and Yenisey Gulf frozen in September?
« on: September 05, 2013, 03:02:02 PM »
How about ASCAT, 25km experimental resolution:

Arctic sea ice / Re: IJIS/JAXA
« on: August 30, 2013, 11:13:41 AM »
A drop of -89k4, but it is based on few 3 swaths:
It's interesting to compare that image to the ASCAT-based classification from the same day:

They seem to be seeing practically the same thing, at least in the Laptev and Kara seas. 

Arctic sea ice / Re: EUMETSAT Sea Ice products?
« on: August 30, 2013, 11:02:06 AM »
Neven, could you add links to the sea ice concentration from OSI SAF onto the Graphs Page?

Antarctica / Re: Potential Collapse Scenario for the WAIS
« on: August 29, 2013, 03:27:59 PM »
How would one stop the potential collapse from happening? I have the feeling that even stopping greenhouse-gas emissions completely doesn't necessarily stop it. That leaves us with terraforming.

Antarctica / Re: Glaciology Basics and Risks - Uncertainties
« on: August 25, 2013, 04:23:08 PM »
Agreed on convergence of the sliding streams. For some detail compare surface velocities in the attached figure 1 from  Rignot(2008, doi:10.1038/ngeo102).
Rignot's group has produced a new map with much improved coverage, see here:

Arctic sea ice / Re: EUMETSAT Sea Ice products?
« on: August 24, 2013, 08:02:17 PM »
I gave the same link one hour and 5 min. earlier in "the canary in the coal mine". Just curious, How did you happen on the link?
Pure coincidence, I'm a satellite-guy and was wondering why Metop was underrepresented. :o

Clouds should have only a negligible effect at C-band - something else is going on.
Then why are clouds plainly visible over open water areas on the images?
That must be the effect of winds on sea-surface roughness (at centimeter-scale), the main product from ASCAT is sea-surface winds after all. High winds -> high surface roughness -> high backscatter.

edit: so very low backscatter means either dead calm open water or a very thin layer of new ice, both of which create very smooth surfaces.

Now as I understand, ASCAT operates on moisture content reflectivity. You can clearly see the reflective “mesh-pack” stand out, the Pole-hole on the fringe, the bleak FYI into the ESAS.
It's a C-band scatterometer, so moisture content and surface roughness affect the backscatter a great deal.
Quote from: werther
To the south (right), two long loops of clouds stand out; one over the Fram, another over the Barentsz Sea. The mid-tone suppression faded almost all other clouds, so you can imagine the water vapour content these bands contain to appear on this pic.
Clouds should have only a negligible effect at C-band - something else is going on.

Arctic sea ice / EUMETSAT Sea Ice products?
« on: August 24, 2013, 12:07:51 PM »

I did not see Eumetsat sea ice products in the Daily Graphs page, I think some of them should add value:

I think ASCAT should be used more in daily analysis, after all it images through clouds, albeit at a rather low resolution.

edit: here's the 12.5km product from today from KNMI:

and main page:

Antarctica / Re: Active destabilization of WAIS?
« on: March 03, 2013, 11:26:11 AM »
So let's say one explosion breaks one cubic kilometer of ice (probably an understatement due to the generated shockwaves). Would such a disturbance in an "optimal" location cause runaway grounding-line retreat, or is such an insult too small by an order of magnitude or two? I guess this is something only modellers can answer.

Antarctica / Active destabilization of WAIS?
« on: March 01, 2013, 10:38:07 AM »
I know this is a scenario from a Bond-film but I've been wondering about the following:

- Would it be possible to destabilize WAIS (at least partly) and cause an acceleration of SLR with a couple of well places nukes?

- Penetrator-missiles could place the nukes at the rock-ice interface at suitable locations upstream of the grounding lines of the Pine Island and Thwaites glaciers.

- Could the ice-stream recover balance after this insult or would this trigger dynamic instabilities and destabilization?

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