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Messages - rauli

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Arctic sea ice / Re: The 2020 melting season
« on: August 23, 2020, 12:31:58 PM »
All, after further consideration I have now deleted or snipped all recent discussion pertaining to a specific user. No one should wake up and find themselves discussed all over the season thread. Whoever missed said discussion, never mind.
Thanks to all who used "report to moderator" today, the advice is helpful.
If anyone feels wronged PM me, don't abuse this thread. For general discussion please head to the forum decorum thread, hopefully not discussing ad hominem but general principles as much as possible.

Arctic sea ice / Re: 2020 Sea ice area and extent data
« on: July 24, 2020, 05:49:59 AM »
Can people please just wait for JCG and Gerontocrat to do their things. It is always funny watching people try to jockey for the honorable position of daily data updater.

It clutters the thread, it doesn't look as nice or neat.

I say this gently, it is most typically new posters who do this. When I was new I was afraid to contribute to the main melting season threads. Still am for the most part. Read. Learn. Find a new way to look at data and then post here. Don't try to horn in by being 14 minutes earlier than JCG.

Policy and solutions / Re: Extinction Rebellion
« on: October 17, 2019, 11:01:09 AM »

Arctic sea ice / Re: Arctic Image of the Day
« on: August 12, 2019, 07:51:15 AM »
Here are a couple of photos I got while flying over the Arctic, from Toronto to Hong Kong on August 1st. (yes, I feel bad about flying due to emissions, but it's not a vacation, we've moved to Jakarta for my wife's work. we will also buy some offsets to try to compensate a bit.)

We were trying to sleep through the 15 hour overnight flight, but I managed to some how wake myself up at the right time to open the window blind and blind myself with the glare.

Again, taken on Aug. 1st, somewhere between Greenland and the North Pole. It seems like a lot of water visible in the leads for this area, even for this time of year. Maybe it's normal recently, but I can't imagine it would've been normal when this area used to be dominated by multiyear ice.

If you want to see the full size images, DM me and I'll email them to you.


Arctic sea ice / Re: The 2019 melting season
« on: June 29, 2019, 02:19:03 PM »
June 1-28

Trailing 5-day median

Click to animate

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 02, 2019, 05:45:56 PM »
There's one thing that has been really tiresome to me lately, and that's meta-discussions, ie a discussion about the discussion. Gerontocrat can do what he likes here, as long as he posts the data. If there's anything anyone wants to take up with him, I'd like to ask them to copy the quote in question, paste it in another thread and comment on it there.

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: June 02, 2019, 03:39:59 PM »
gerontocrat and Juan

keep doing what you is why I visit this thread daily.

Greenland and Arctic Circle / Re: The 'Very Big Chunk' poll
« on: May 12, 2019, 12:14:50 AM »
Latest Sentinel image. I have never seen the Lincoln look like this:
AH, how long have you been looking? (Longer than 3 years?)
Maybe I'm jaded, but I presume I've seen the Lincoln Sea 'totally' chopped up like this.  Maybe only much later in the melting season (as someone suggested), which would be bad enough (for the health of an icy Arctic) then.

AH and Tor,

This year is quite unusual and far ahead of others. In 20 years of watching the ice conditions, this is both horrible and not unexpected. I have been watching the ice closely ever since the Terra and Aqua satellites first came on line, and sporadically before that with the earlier imagery. In those first years of this new age, your had to go to the NASA website for Terra and Aqua and wander through the individual photo images in various sizes and resolutions and bands. It is so much easier now to just look at the mosaic on EOSDIS, pick your layers, run little moves, scan around, rotate and ...

I remember so clearly watching in horror when the multiyear ice failed north of Ellesmere for the first time in recorded history and drained an ephemeral lake that contained a unique ecosystem that was estimated to be over 3,000 years old.

Now it is routine to see the ice break up in the Lincoln sea, though nothing like what we are seeing this year.

More startling is the extreme shattering of the formerly multiyear ice to the west of the Lincoln sea along the north coast of Ellesmere. The long wide rip in the ice all the way to the other end of the northwest passage has happened before (in recent years). But I do not recall the ice ever shattering along the arctic side of that open lede like it is this year.

It has been happening since before 2000, and was especially severe in 2004, 2005, and 2008, then in the past few years. Still, the breakup this year is unprecedented, just as the breakup of the Lincoln Sea is.

There is simply no integrity at all left to what used to be land fast multiyear ice. The only exceptions might be in some of the channels between the islands that make up Ellesmere.

New this year is the connection between the shattered ice moving north of Greenland and exiting into the Atlantic with the shattered ice in the Lincoln Sea exiting to the south.

I would not be surprised at all this year or in the next few to see a complete breakup of the former multi-year ice all the way from the Atlantic to the Beaufort Sea and a hundred miles off shore of Ellesmere, with shattered ice being chewed up and spit out into the Atlantic, out through the Lincoln Sea and into the Beaufort simultaneously. We already see that happening in segments. And the Lincoln Sea breakup is now fully connect to the breakup north of Greenland. The rip along Ellesmere has nearly completed the free flowing connection of shattered ice moving to the Beaufort.

It used to be that the currents in the Lincoln Sea oscillated strongly across the "ice bridge" between flowing into and out of the arctic through the Lincoln Sea. Now it seems to be almost uniformly out of the Lincoln Sea to the south, with the ice being thin enough to be shattered on contact with the basalt.

As the old ice is rapidly lost, the average thickness of the ice is falling quickly, and the end of the ice rapidly approaches.


I looked at the bedrock map tealight recently published here in the "What's new in Antarctica?" thread.
I looked at the connection between the Antarctic Peninsula (AP) and the ridge that forms the Transantarctic Mountains (TAM). If you put all the ice away there is a big gap between AP and TAM (white circle in the map). To the northeast is Weddell Sea, to the Northwest it is the WAIS and the PIG, followed by the Amundsen Sea. So once there should be a free flow of ocean waters between Weddell Sea and Amundsen Sea which probably puts all ocean currents in that area upside down. Is there any historical evidence that this area had ever been open? And what would that mean to the stability of the WAIS (if it still exists in parts at that stage)? Is there any danger of MISI or other mechanisms of that circled area caused by / coming from Weddell Sea?

Antarctica / Re: What's new in Antarctica ?
« on: April 23, 2019, 01:49:47 AM »
The Antarctic Bedrock data was over 10 times harder to align than Greenland. There are hardly any landmarks, just plain white and with fast ice or ice shelfs you don't even know where the land begins. I had to use huge area images to align islands and then cut it down to individual glaciers. The bedrock resolution is just 1km/px as opposed to 0.15km/px for Greenland data.

Arctic sea ice / Re: 2019 sea ice area and extent data
« on: April 16, 2019, 12:14:49 PM »
As far as a B.O.E. is concerned do we not expect to see melt alter as we approach such an event?

By the time we are down to the last dregs they will no doubt be surrounded by warmed waters and all be of a similar remnant thickness?

I imagine the end coming very fast when it does?

Antarctica / Re: Thwaites Glacier Discussion
« on: February 09, 2019, 12:09:35 PM »
I've been following this thread for a while, but it's often very hard in this complex zone to figure out scale of things, and what is what, default explicit scale and orientation of pictures. Would it be difficult to have some reference map, with scale and orientation, on which background the different pictures posted here could be localized? Or are things so mobile there that the very notion of such a map is impossible?

The UK's Met Office has projected that most likely, sometime in the next five years, GMSTA will at least temporarily exceed the IPCC's aspirational 1.5C target:

Title: "Met Office: World has 10% chance of ‘overshooting’ 1.5C within five years"

Extract: "The results find that, over a five-year period from November 2018 to October 2023, the global average temperature rise is likely to be between 1.03C and 1.57C. This is shown on the chart below, where blue shading represents the range of expected temperature rise for this period, when compared to temperatures in the “pre-industrial period” (1850-1990)."

Caption: "Expected rise in global temperature from November 2018 to October 2023 (blue), relative to “pre-industrial” temperatures (1850-1900). Actual temperature rise from 1960 to October 2018 is shown in black, the results of previous Met Office decadal projections are shown in red (hindcast) and results from the “Coupled Model Intercomparison Project” (CMIP5) are shown in green. There is a gap between the black line and blue shading because the observational data finishes in October 2018 and the projections start in November 2018. Shading shows range of confidence. Source: Met Office."

See also:

Arctic sea ice / Re: Latest PIOMAS update (January)
« on: February 05, 2019, 09:32:16 AM »
While waiting for the lastest January data, here is an animation of the full range 1979-2018. Made possible by a recent inclusion of 1979-1999 daily thickness data.

Displayed are thickness data every 5th day to keep the file size relatively limited.

It is coded as an mp4 file, experimental for me, over 13meg in size, see it works for you.

Arctic sea ice / Re: What's new in the Arctic ?
« on: November 07, 2018, 09:54:48 AM »
The KNMI (Royal Netherlands Meteorological Institute) issued a small news report (what they call climate-message).

The message is that the decline of Arctic Sea Ice has been mostly in thickness, not area. And that will change when the ice get thinner. The consequence of this is that Arctic warming will amplify as AlbertoAlbedo will drop.

On twitter one of the scientists speculates that Arctic amplification will increase from current 2-3 to future 4-5.

The message is in Dutch, but should be readable with Google translate:

We need climate models to make the best estimates of future changes in the climate. KNMI plays an important role in the development of a precise global climate model (EC-Earth) with which we can study the consequences of Arctic changes. The model results show that sea-ice retreat will play an increasingly important role in the loss of Arctic sea ice in the future (figure 1). Because this increases the warming of the Arctic relatively strongly (compared to the thinning), the temperature in the Arctic is expected to rise more and more quickly.

Figure 1. Future simulation of Arctic sea ice thickness (SIT) and sea ice surface (SIA) showing that the sea ice thickness is decreasing nowadays, while in the future the sea ice surface will decrease.

Arctic sea ice / Re: Latest PIOMAS update (October)
« on: October 06, 2018, 06:12:05 PM »
So extrapolating data up to 2010, it was 5 years ahead and extrapolating data up to 2018, it was 6 years ahead

Indeed, the exponential extrapolation for the September PIOMAS minimum has been basically stuck at "ice free in (approximately) 5 years".  Gompertz follows a similar path but is a bit further in the future.  And the end date for the linear extrapolation decreased in the 2000s but didn't change much in the 2010s.

Arctic sea ice / Re: The 2018 melting season
« on: August 08, 2018, 11:18:16 AM »
Made an animation of the opening up north of Greenland. First I created composites of near time images to quit the clouds but tried to respect the general movement as much as possible. Then I applied contrast enhancement in some cases to quit thin cloud covers and mist.

Any way of telling how thick they are from the freeboard ?

Yes by measuring the shadow...requires calculating the elevation-angle of the Sun at the time of the acquisition.

I did some measurements and currently the southern branch and it's tabular icebergs have 68.8m freeboard. For comparison during the record low in August 2015 the freeboard was 125m.

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