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Laurent

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What's new in the Arctic ?
« on: October 09, 2013, 04:11:00 PM »
About svalbard bears...
Just to point the heat flux coming north of svalbard !
It doesn't seem to be an upwelling but a move of the atlantic !
Comments are welcome !

Despite the giant protests worldwide, the russians tighten the grip...
http://www.bbc.co.uk/news/world-europe-24461644

Laurent

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Re: What's new in the Arctic ?
« Reply #1 on: October 25, 2013, 10:22:50 AM »
Greenland's parliament voted on Thursday (24 October) to end a decades-long prohibition on mining for radioactive materials like uranium, further opening up the country to investors from Australia and China eager to tap its vast mineral resources.

http://www.euractiv.com/sustainability/greenland-votes-allow-uranium-ra-news-531310?utm_source=RSS_Feed&utm_medium=RSS&utm_campaign=EurActivRSS

Andreas T

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Re: What's new in the Arctic ?
« Reply #2 on: October 25, 2013, 11:49:49 AM »
also on warm waters around Svalbard http://www.awi.de/en/news/press_releases/detail/item/escaping_the_heat_the_atlantic_cod_conquers_the_arctic/?cHash=a37b1f4d9f2329fe96868717d233b68b
a reminder that CO2 does not only warm but also acidifies the ocean.

domen_

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Re: What's new in the Arctic ?
« Reply #3 on: November 22, 2013, 12:45:23 PM »

ChrisReynolds

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Re: What's new in the Arctic ?
« Reply #4 on: November 23, 2013, 10:28:02 AM »
Domen,

Temperatures are colder than recent years in the Arctic right now. Methane destruction by OH radicals is temperature dependent.

For what it's worth I don't trust Sam Camara's blog ever since they stopped posting my comments on a certain thread. No reason was given, they just truncated the discussion when I was making comments contrary to their meme.

Theta

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Re: What's new in the Arctic ?
« Reply #5 on: November 23, 2013, 11:09:54 AM »
Reports of very big methane releases all over the Arctic:



http://arctic-news.blogspot.com/2013/11/high-methane-levels-all-over-arctic-ocean.html

I believe something similar to this happened last winter also, when there were Methane Releases from a particular area in the Arctic Sea, even looking through previous blog posts made by the blog will illustrate this.

Of course a new development could have taken place if one takes the earthquate that occurred in the Arctic Ocean into consideration (http://arctic-news.blogspot.ie/2013/09/methane-release-caused-by-earthquakes.html).

For now though, the high Methane amounts over the Arctic Ocean, according to Arctic News, appear to have been caused by wind blowing Methane around as a result of the "Coriolis Effect".
Can't think of a signature

domen_

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Re: What's new in the Arctic ?
« Reply #6 on: November 23, 2013, 11:25:54 PM »
Thanks for clarification!

Quote
Methane destruction by OH radicals is temperature dependent.
Does that mean methane breaks into CO2 faster or slower during winter?

wili

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Re: What's new in the Arctic ?
« Reply #7 on: November 24, 2013, 01:55:35 AM »
Slower/hardly at all.
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

johnm33

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wili

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Re: What's new in the Arctic ?
« Reply #9 on: November 24, 2013, 11:52:23 PM »
Thanks for that link, john. Hope you don't mind that I copied it to a number of other fora.
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

wili

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Re: What's new in the Arctic ?
« Reply #10 on: November 25, 2013, 12:18:19 AM »
Here's the link to the article (thanks to prokaryote at RC):

http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2007.html

Ebullition and storm-induced methane release from the East Siberian Arctic Shelf


abstract:
Quote
Vast quantities of carbon are stored in shallow Arctic reservoirs, such as submarine and terrestrial permafrost. Submarine permafrost on the East Siberian Arctic Shelf started warming in the early Holocene, several thousand years ago. However, the present state of the permafrost in this region is uncertain.

Here, we present data on the temperature of submarine permafrost on the East Siberian Arctic Shelf using measurements collected from a sediment core, together with sonar-derived observations of bubble flux and measurements of seawater methane levels taken from the same region. The temperature of the sediment core ranged from −1.8 to 0 °C. Although the surface layer exhibited the lowest temperatures, it was entirely unfrozen, owing to significant concentrations of salt.

On the basis of the sonar data, we estimate that bubbles escaping the partially thawed permafrost inject 100–630 mg methane m−2 d−1 into the overlying water column. We further show that water-column methane levels had dropped significantly following the passage of two storms. We suggest that significant quantities of methane are escaping the East Siberian Shelf as a result of the degradation of submarine permafrost over thousands of years.

We suggest that bubbles and storms facilitate the flux of this methane to the overlying ocean and atmosphere, respectively.

(My emphases and formatting.)
"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

Laurent

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Re: What's new in the Arctic ?
« Reply #11 on: December 04, 2013, 09:50:27 PM »
http://uxblog.idvsolutions.com/2013/07/a-breathing-earth.html
The earth is breathing
Breath in breath out, once again, ppppfffffffaaa.....fffffffuuuuu

wili

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Re: What's new in the Arctic ?
« Reply #12 on: December 05, 2013, 12:17:01 AM »
Thanks for that, L. Have you seen this one with a similar name but different focus:

http://www.breathingearth.net/

(I find the sound effects slightly creepy after a while.)

"A force de chercher de bonnes raisons, on en trouve; on les dit; et après on y tient, non pas tant parce qu'elles sont bonnes que pour ne pas se démentir." Choderlos de Laclos "You struggle to come up with some valid reasons, then cling to them, not because they're good, but just to not back down."

Laurent

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Re: What's new in the Arctic ?
« Reply #13 on: December 05, 2013, 09:03:34 AM »
You already posted it the 4 th november
Jim, since you like maps, here's a similar one, but with indications of GHG release as well as births and death, and with the added benefit of slightly creepy sound effects.

http://www.breathingearth.net/

The pulsing beat of births in India is quite...impressive.

On the issue of the transformation of waste, has anyone said it better than:

  ?

(She really gets into it at about the three minute mark.)
I don't like much looking at this numbers globaly, it is depressing !
Interesting but depressing !

Laurent

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Laurent

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Re: What's new in the Arctic ?
« Reply #15 on: October 23, 2014, 04:09:56 PM »
2014 Arctic sea ice extent - 6th lowest in millennia
http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/oct/20/2014-arctic-sea-ice-extent-6th-lowest-in-millennia

I like seeing things through a perspective !

ChrisReynolds

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Re: What's new in the Arctic ?
« Reply #16 on: October 23, 2014, 06:55:56 PM »
Minor fact check Laurent, sorry I can't stop myself.  :-[

Kinnard et al use late summer extent, which they define as average August extent. Whether one uses the August monthly average of the daily NSIDC Extent, or the NISDC monthly extent data for August, 2014 ranks 7th, not 6th.

Not that this changes the picture significantly.

SCYetti

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Re: What's new in the Arctic ?
« Reply #17 on: October 24, 2014, 05:22:16 PM »
Chris Reynolds, the article in the Guardian was quoting the NSIDC when it said 6th lowest:

 "Following the seasonal daily minimum of 5.02 million square kilometers (1.94 million square miles) that was set on September 17, 2014 (6th lowest in the satellite record), Arctic sea ice has started its seasonal cycle of growth. Arctic sea ice extent averaged for the month of September 2014 was 5.28 million square kilometers (2.04 million square miles), also the 6th lowest in the satellite record. This is 1.24 million square kilometers (479,000 square miles) below the 1981 to 2010 average extent, and 1.65 million square kilometers (637,000 square miles) above the record low monthly average for September that occurred in 2012."
 I think 6th or 7th depends on whose and which estimate one uses.
« Last Edit: October 24, 2014, 08:41:26 PM by SCYetti »

ChrisReynolds

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Re: What's new in the Arctic ?
« Reply #18 on: October 24, 2014, 09:53:10 PM »
Sorry SCYeti, but whenever one compares to Kinnard et al it is August extent that counts, because that is what their graph shows. Yes the September minimum for 2014 was 6th, but the Kinnard data refers to an estimate based on August.

I know it is a nit-picking detail, but we should be careful not to be slack in our comparisons when we don't have to be.


OSweetMrMath

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Re: What's new in the Arctic ?
« Reply #19 on: October 25, 2014, 02:23:25 AM »
But Laurent was quoting the title of the Guardian article. And the Guardian article quotes several sources and reprints several graphics, most of which state or refer to the extent as 6th lowest. It happens that the one graphic Laurent reposted shows the extent as 7th lowest. If you want to claim the Guardian got it wrong for not stating that by this one graph, it's 7th lowest, I suppose that's your choice. But correcting Laurent, as you appear to be doing, seems misplaced.

ChrisReynolds

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Re: What's new in the Arctic ?
« Reply #20 on: October 25, 2014, 08:03:01 AM »
OMSM,

I'm not trying to correct anyone, I'm just pointing out that Kinnard is for August. (I have said that this is a minor issue in the context of 1450 years of data)

Laurent

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Re: What's new in the Arctic ?
« Reply #21 on: October 25, 2014, 09:46:24 AM »
I am not a specialist like you, I am just reporting the news that I find to be of interest concerning climate change and other consequences of our collective actions. If you think 6th or 7th rank is important concerning the long term trend...oh, ok. Personnally I find that really scary either 6th or 7th...
But continue to argue if you think there is something wrong ; if I can do something about, I will do it.  ;)

viddaloo

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Re: What's new in the Arctic ?
« Reply #22 on: October 25, 2014, 10:51:55 AM »
Whether one uses the August monthly average of the daily NSIDC Extent, or the NISDC monthly extent data for August, 2014 ranks 7th, not 6th.
That's true, but we were 5th lowest just a fortnight later. Clearly, judging a year only by 1 day out of 365 is unscientific. According to the Yearly Average we are 4th.
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SCYetti

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Re: What's new in the Arctic ?
« Reply #23 on: October 25, 2014, 02:56:57 PM »
4th lowest? Thanks for that Viddaloo. In the past 6 weeks or so your posts on the yearly average and Chris Reynolds's freezing degree day posts have answered questions of mine. To me the state of the ice is important. However it is just one indicator of the total energy in the Arctic system. It may be as significant or even more significant that the water flowing out through the Greenland Sea is .5 degrees C warmer than a few years ago. If it is a trend.
« Last Edit: October 25, 2014, 03:04:55 PM by SCYetti »

SCYetti

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Re: What's new in the Arctic ?
« Reply #24 on: October 25, 2014, 03:10:31 PM »
OMSM,

I'm not trying to correct anyone, I'm just pointing out that Kinnard is for August. (I have said that this is a minor issue in the context of 1450 years of data)
Those who post comments here are interested in accuracy as are you. Writers at newspapers are more interested in sensationalism thus 6th instead of 7th. If they had known to talk to Viddaloo their  headline would have read 4th lowest.

viddaloo

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Re: What's new in the Arctic ?
« Reply #25 on: October 25, 2014, 03:13:12 PM »
Average extent is 4th, average volume is 5th. I think most of us agree that volume is a better indicator of the overall state of the ice and thus the heat/enthalpy of the system? Only 2010–2013 are lower than 2014 in yearly average volume, so the latest 5 years are the lowest 5 years (in x millennia).
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ChrisReynolds

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Re: What's new in the Arctic ?
« Reply #26 on: October 26, 2014, 09:35:18 AM »
Sorry I raised the issue Laurent. Yes I agree, and as I have now said around four times, 6th / 7th in the context of 1450 years makes little difference.

Whether one uses the August monthly average of the daily NSIDC Extent, or the NISDC monthly extent data for August, 2014 ranks 7th, not 6th.
That's true, but we were 5th lowest just a fortnight later. Clearly, judging a year only by 1 day out of 365 is unscientific. According to the Yearly Average we are 4th.

What does Kinnard et al use to construct their graph?

September daily minimum? No.
September monthly average minimum? No.
Yearly average? No.
August Average, which they call 'late summer'. Yes.

I'm walking away from this now.

viddaloo

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Re: What's new in the Arctic ?
« Reply #27 on: October 26, 2014, 06:04:08 PM »
This graph showing 4th hammers in the 4th–ness, I believe, if still necessary.
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viddaloo

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Re: What's new in the Arctic ?
« Reply #28 on: November 06, 2014, 10:45:55 AM »
Monster Storm to Pound Bering Sea



Quote
Large waves and hurricane-force winds are expected to be the highest impacts with waves in some areas topping 45 feet Friday night and into Saturday.
Waves this large can quickly turn deadly, tossing around ships sailing in the area.

Could perhaps throw some sea ice around?
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jdallen

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Re: What's new in the Arctic ?
« Reply #29 on: November 06, 2014, 05:55:39 PM »
Monster Storm to Pound Bering Sea



Quote
Large waves and hurricane-force winds are expected to be the highest impacts with waves in some areas topping 45 feet Friday night and into Saturday.
Waves this large can quickly turn deadly, tossing around ships sailing in the area.

Could perhaps throw some sea ice around?
The effect on ice I suspect will be Inconsequential.

The load of *moisture* the storm will haul to high latitudes I think is more consequential.

Most consequential will be, if this storm suggests a pattern has been established, whereby there is a huge increase in export of moisture and heat to the arctic during winter.  Nori is the second or third substantial storm to follow this track this year, I believe. While sensational in size, more of a concern to me for the possible pattern change.

This could imply the return of the "super high" which dominated the NE Pacific for most of the last two years, which has dried out California. Not good.
This space for Rent.

viddaloo

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Re: What's new in the Arctic ?
« Reply #30 on: November 06, 2014, 07:39:49 PM »
Let's hope it never reaches the ESAS.
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Laurent

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Re: What's new in the Arctic ?
« Reply #31 on: November 29, 2014, 01:24:04 PM »
Some news on the Arctic.
http://www.polarsea360.com/episodes/01/

Available tonight on arte.tv (in French and German)
http://polarsea360.arte.tv/fr/

LRC1962

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Re: What's new in the Arctic ?
« Reply #32 on: December 06, 2014, 11:51:54 PM »
On a technological side of things came acrosss this news piece http://www.cbc.ca/news/technology/thermal-imaging-sensor-predicting-winter-weather-in-arctic-tests-this-spring-1.2859271 . I wonder if the FFIR could also help with giving us an idea how much heat is being trapped in the Arctic at any given point in time or how much heat is getting imported into the Arctic?
"All truth passes through three stages: First, it is ridiculed; Second,  it is violently opposed; and Third, it is accepted as self-evident."
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jdallen

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Re: What's new in the Arctic ?
« Reply #33 on: December 07, 2014, 09:24:00 AM »
I wonder if the FFIR could also help with giving us an idea how much heat is being trapped in the Arctic at any given point in time or how much heat is getting imported into the Arctic?

Oh! That would be a wonder! Heat budget is everything in sorting out what will happen. Now, if we could just get more moored sub-pack sensors to get us more water column and ice thickness data...
This space for Rent.

viddaloo

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Re: What's new in the Arctic ?
« Reply #34 on: December 15, 2014, 12:17:59 AM »
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Laurent

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Re: What's new in the Arctic ?
« Reply #35 on: December 15, 2014, 10:05:07 AM »
Arctic sea ice volume holds up in 2014
http://www.bbc.com/news/science-environment-30399079

viddaloo

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Re: What's new in the Arctic ?
« Reply #36 on: December 15, 2014, 07:13:28 PM »
Arctic sea ice volume holds up in 2014
http://www.bbc.com/news/science-environment-30399079

It has daily sea ice volume figures but won't share those with the European population? Then I'm not so sure we really need the Cryosat satellite.
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Laurent

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Re: What's new in the Arctic ?
« Reply #37 on: December 15, 2014, 07:33:57 PM »
Yes, strange politic, remember there is a share older behind ESA. We need it to correlate others datas but we can do without the daily news...I think.

Laurent

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Re: What's new in the Arctic ?
« Reply #38 on: December 15, 2014, 08:18:36 PM »
More on Denmark claim.
Denmark challenges Russia and Canada over North Pole
http://www.bbc.com/news/world-europe-30481309

viddaloo

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Re: What's new in the Arctic ?
« Reply #39 on: December 15, 2014, 08:43:24 PM »
Yes, strange politic, remember there is a share older behind ESA. We need it to correlate others datas but we can do without the daily news...I think.
  • European taxpayers paid for this satellite program and research
  • There is no other program in the world that has daily volume data

Quote from: BBC link=http://www.bbc.com/news/science-environment-30399079
The deep lows in this short series were 5,300 and 5,400 cubic km in 2011 and 2012, respectively. But then came the bounce back, with colder weather over the following two years resetting the minimum. [...]

"Now that Cryosat can deliver near real-time observations of sea-ice thickness that agree to within 1% of the climate-quality measurements, which are not rapid enough for operational purposes, Arctic nations will be able to make sure that any future maritime activities are done with safety and care."

« Last Edit: December 15, 2014, 09:19:36 PM by viddaloo »
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crandles

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Re: What's new in the Arctic ?
« Reply #40 on: December 15, 2014, 09:03:20 PM »
I thought Cryosat2 had daily data for small slices but it took a month to cover the whole Arctic so I don't think it really has daily volume numbers.

ChrisReynolds

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Re: What's new in the Arctic ?
« Reply #41 on: December 15, 2014, 09:39:31 PM »
Arctic sea ice volume holds up in 2014
http://www.bbc.com/news/science-environment-30399079

What interested me was at the start:

Quote
The spacecraft observed 7,500 cu km of ice cover in October when the Arctic traditionally starts its post-summer freeze-up.

This was only slightly down on 2013 when 8,800 cu km were recorded

PIOMAS finds 6,908 cu km in October 2013, and 8,104 cu km in October 2014. The numbers are not (as I understand) directly comparable between PIOMAS and Cryosat 2, although they're close.

What strikes me is that PIOMAS shows increasing volume, while Cryosat 2 shows a drop of volume.

PS, Schweiger et al find:

Quote
a conservative estimate for October Arctic ice volume uncertainty of +/- 1.35x103 km3

So at 1.196k km^3 gain from October 2014 to October 2013 the increase is not outside uncertainty bounds for PIOMAS. So we can't be sure it's happened, although the above stated uncertainty is conservative, I think 2014 has a greater volume. Sorry, but I don't trust Cryosat 2 yet.
« Last Edit: December 15, 2014, 09:45:12 PM by ChrisReynolds »

viddaloo

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Re: What's new in the Arctic ?
« Reply #42 on: December 15, 2014, 10:21:06 PM »
IMO it's hard to trust anyone who doesn't publish the background data. I paid for that satellite!
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Steven

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Re: What's new in the Arctic ?
« Reply #43 on: December 18, 2014, 01:26:57 PM »
NOAA has released its annual Arctic Report Card:
http://www.arctic.noaa.gov/reportcard/index.html

Click on the menu on the left of that webpage for the sections about

Air Temperature
Terrestrial Snow Cover
Greenland Ice Sheet
Sea Ice
Sea surface temperature

etc.

crandles

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Re: What's new in the Arctic ?
« Reply #44 on: December 18, 2014, 02:08:36 PM »
Quote
Recent studies of the impact of snow layer properties on CryoSat-2 freeboard retrieval conclude that radar backscatter from the snow layer may lead to a bias in sea ice freeboard if it is not included in the retrieval process (Ricker et al. 2014, Kwok et al. 2014). Current sea-ice thickness data products from CryoSat-2 are, therefore, based on the assumption that the impact of the snow layer on radar freeboard is constant from year to year and snow depth can be sufficiently approximated by long-term observation values.

With these assumptions, updated radar freeboard and sea-ice thickness maps of the CryoSat-2 data product from the Alfred Wegner Institute (Fig. 4.4) show an increase in average freeboard of 0.05 m in March 2014 compared to the two preceding years (2012: 0.16 m, 2013: 0.16 m, 2014: 0.21 m). This amounts to an increase of mean sea-ice thickness of 0.38 m (2012: 1.97 m, 2013: 1.97 m, 2014: 2.35 m). The mean values were calculated for an area in the central Arctic Ocean where the snow climatology is considered to be valid. Excluded are the ice-covered areas of the southern Barents Sea, Fram Strait, Baffin Bay and the Canadian Arctic Archipelago. The main increase of mean freeboard and thickness is observed in the multi-year sea ice zone north-west of Greenland, while first year sea ice freeboard and thickness values remained typical for the Arctic spring.


Quote
Fig. 4.4. Arctic sea ice freeboard (left) and thickness (right) maps for March retrieved from the ESA CryoSat-2 satellite for the period 2012-2014. The areas with the darkest shading, west and east of Greenland, the Canadian Arctic Archipelago and the Kara Sea, are outside the valid region for long-term snow observations. Freeboard is the height of the ice surface above the water level.

More volume in 2014 than 2013 per Cryosat2 which seems different from the ESA report. Above seems to agree to PIOMAS better than ESA report. at March 2014

Perhaps ESA is suffering from the 'radar backscatter from the snow layer' issue?
« Last Edit: December 18, 2014, 04:32:03 PM by crandles »

viddaloo

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Re: What's new in the Arctic ?
« Reply #45 on: December 18, 2014, 03:14:56 PM »
More volume in 2014 than 2013 per Cryosat2 which seems different from the ESA report. Above seems to agree to PIOMAS better than ESA report.
Not quite. We already knew from the BBC/ESA story AGU abstracts that 'spring' 2014 was higher than 2013. The turn was somewhere between 'spring' (probably March) and October + 'October and November', where 2014 was lower.

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«Between autumn 2010 and spring 2013, there was a 14% and 5% reduction in autumn and spring Arctic sea ice volume, respectively, in keeping with the long-term decline in extent.»
Autumn 2010 to autumn 2012: 14% drop in sea ice volume.
Spring 2011 to spring 2013: 5% drop in sea ice volume.

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«However, since then there has been a marked 41% and 9% recovery in autumn and spring sea ice volume, respectively, more than offsetting losses of the previous three years.»
Autumn 2012 to autumn 2014: 41% increase in sea ice volume.
Spring 2013 to spring 2014: 9% increase in sea ice volume.

Add to that a 15% drop in reported October sea ice volume from 2013 to 2014 and a 6% drop by 1st or 15th December from 2013, and you have a picture of an annual average ice volume that clearly peaked somewhere between 'spring' 2014 (still up 9% over the previous year) and October 2014 (down 15%), and that is very different from the PIOMAS AAV.
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jdallen

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Re: What's new in the Arctic ?
« Reply #46 on: December 18, 2014, 05:59:56 PM »
In view of recent increases in moisture being imported into the arctic, and apparent increases in snowfall, and the note Crandalls included, I get a subtle indication that the interpretation of cryosat-2 data may be biased high.  I'm finding myself wondering how far their estimate of snowfall may be off.  They as much as admit they are making an educated guess.
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ChrisReynolds

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Re: What's new in the Arctic ?
« Reply #47 on: December 18, 2014, 07:57:38 PM »
In view of recent increases in moisture being imported into the arctic, and apparent increases in snowfall, and the note Crandalls included, I get a subtle indication that the interpretation of cryosat-2 data may be biased high.  I'm finding myself wondering how far their estimate of snowfall may be off.  They as much as admit they are making an educated guess.

From what I recall of past reading of Cryosat 2 papers they use an assumed average seasonal cycle of snow cover. Variations either side of that can affect the calculated freeboard.

Ah, yes, Laxon 2013, "CryoSat-2 estimates of Arctic sea ice thickness and volume", states that they use a snow cover climatology from Warren 1999.

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Warren, S. G., I. G. Rigor, N. Untersteiner, V. F. Radionov, N. N. Bryazgin,
Y. I. Aleksandrov, and R. Colony (1999), Snow depth on Arctic sea ice,
J. Climate, 12(6), 1814–1829.

However in that 2013 paper they vary the snow depth using more recent research depending on the underlying ice type (MYI/FYI). However there have been two papers I know of proposing changes to the algorithm.
Ricker et al 2014
http://www.the-cryosphere.net/8/1607/2014/tc-8-1607-2014.pdf
Kurtz et al 2014
http://www.the-cryosphere.net/8/1217/2014/tc-8-1217-2014.pdf
(The NOAA Report card mentions another paper I have not read by Kwok).

I don't know if the recent Cryosat data incorporates improvements on the Laxon 2013 paper method. From my reading of the reportcard, as quoted by Crandles I suspect not.

Steven,

Thanks for the heads up on that.

jdallen

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Re: What's new in the Arctic ?
« Reply #48 on: December 19, 2014, 04:46:27 AM »
From what I recall of past reading of Cryosat 2 papers they use an assumed average seasonal cycle of snow cover. Variations either side of that can affect the calculated freeboard.

Ah, yes, Laxon 2013, "CryoSat-2 estimates of Arctic sea ice thickness and volume", states that they use a snow cover climatology from Warren 1999.
That I think I'll chase down.  The date by itself suggests a problem considering how different the weather and ice cover is now as compared to 15 years ago.
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ChrisReynolds

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Re: What's new in the Arctic ?
« Reply #49 on: December 19, 2014, 06:39:01 PM »
From what I recall of past reading of Cryosat 2 papers they use an assumed average seasonal cycle of snow cover. Variations either side of that can affect the calculated freeboard.

Ah, yes, Laxon 2013, "CryoSat-2 estimates of Arctic sea ice thickness and volume", states that they use a snow cover climatology from Warren 1999.
That I think I'll chase down.  The date by itself suggests a problem considering how different the weather and ice cover is now as compared to 15 years ago.

Must admit I've never read it. Anyway, it's here:
http://seaice.apl.washington.edu/Papers/WarrenEtal99.pdf