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Messages - oren

Pages: [1] 2 3 ... 24
1
Consequences / Re: Floods
« on: Today at 05:47:52 PM »
Fighting against the sea in such a manner is sheer idiocy. At such costs, it is the very definition of unsustainable, especially given accelerating sea level rise. Sometimes you just have to cut you losses, the earlier the better.

2
Science / Re: 2017 Mauna Loa CO2
« on: Today at 07:52:07 AM »
Thanks ASLR. These charts make me seriously question the Sapiens part in HS.

3
Arctic sea ice / Re: What the Buoys are telling
« on: Today at 07:20:29 AM »
And here's another one with just 3 frames which have similar shadows. Definitely something is going on in the foreground. Click.

4
Arctic sea ice / Re: What the Buoys are telling
« on: Today at 07:16:24 AM »
As the movie is not updating unfortunately, here's a very crude animation of images saved on this thread. ImageJ forced me for some reason to go down to 8-bit color. In any case, the shifting lighting make it very hard to compare between frames. Needs a click.

5
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: Today at 07:00:46 AM »
The Lincoln Sea breakup continues in an ugly way.
On the other hand, if it drifts west this chunk of fast ice is another chance to jam the entrance to Nares, making for interesting watching before it shatters. Though I find it more probable it drifts towards the Fram instead.

6
The sill near the end of Petermann fjord is indeed deeper than the sill out in the Lincoln Sea, so it's the Lincoln Sea sill that determines the temperature and salinity of the water chewing away at Petermann Glacier. I agree that buttressing may slow glacial flow, but don't believe it has a measurable effect on Petermann.

Can I again do a quick plug for:
https://icyseas.org/
Terry you're correct on all fronts, also thanks for reminding me of the admirable Andreas M's blog

7
Policy and solutions / Re: Coal
« on: May 28, 2017, 08:24:41 PM »
SH, I am depressed too, but Bob here is doing his best to cheer me up. A pretty good job sometimes.

8
Arctic sea ice / Re: The 2017 melting season
« on: May 28, 2017, 12:33:24 PM »
DMIs model shows temps above freezing point over a large part of Beaufort Sea as well as partly over the CAB.
The Hudson and Foxe BASIN ad well. Wall-to-wall meltponds visible in Hudson's Bay.
My untrainded eyes insist that the Beaufort and the CAA have acquired a bluish tinge as well.

9
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: May 28, 2017, 12:02:46 PM »
Andreas - superb animation, thanks. It's amazing how the pieces break and accelerate at the entrance, like going down the drain...

10
In a weird sort of way, the blatant denial of the Trump people is better than the hidden denial and intentional scientific confusion that we had previously. It helps brings climate change to the table as a major issue, and gets people to be less confused.

11
TB, there is a sill between the fjord and Nares Strait. The fjord is actually deeper.
As for effects of early Nares clearing on local glaciers, I would first look at Humboldt glacier, draining into Kane Basin, as it is far wider and its calving front much closer to the area of action. http://forum.arctic-sea-ice.net/index.php/topic,800.0.html
Petermann is much more stable than other Greenland glaciers, despite several massive calvings in the last few years.
In general I agree with the statement posted up-thread that marine-terminating glaciers are not affected by sea ice cover nearby, and are mostly affected by deeper water temps and currents. I personally believe Zachariae Isstrom is a rare exception, where the calving area is covered by sea ice year-round except some years in August, and the sea ice and iceberg melange is compressed against rocks further ahead, potentially slowing the glacier somewhat. Not albedo, but a small buttressing effect. Even this is just my personal layman opinion, with lots of caveats and unsupported by science. Other potential effects might be more waves and storms when sea ice is absent, but this requires a larger body of water, not a narrow fjord.
Note in the Nares albedo plays a much smaller role than usual as there is an almost-constant southbound current, carrying any accumulated heat out of the Arctic proper. Perhaps if the sea ice were to clear inside the Petermann fjord itself much earlier than usual, then accumulated heat might have some small effect on the glacier. But remember that the thickness of the floating part of the glacier is around 200 meters, and the calving is usually along cracks developing behind the front. Hard to affect by sea surface temps.
Hope this mess is somewhat helpful...

12
Consequences / Re: Climate change, the ocean, agriculture, and FOOD
« on: May 27, 2017, 08:19:45 PM »
bbr1234 this needs to be taken to the thread I linked or any other relevant thread, but not here.

13
Any thoughts on the state of the Petermann Glacier right now, May 27, in relation to open Nares and Lincoln Sea, and warmer SSTs ? And likely near future?
I'm not sure if Petermann is affected by the opening of Nares or not. But in any case it will be interesting to note when the sea ice clears from inside the fjord, and compare it to previous years.

14
Consequences / Re: Climate change, the ocean, agriculture, and FOOD
« on: May 27, 2017, 02:45:49 PM »
Gerontocrat, bbr1234 has been discussing positive snow anomalies for a while. You may find the thread "negative feedback of positive snow anomalies", https://forum.arctic-sea-ice.net/index.php/topic,1932.0.html, interesting. It has been set up to discuss this theory, which I personally don't subscribe to.

15
Policy and solutions / Re: Nuclear Power
« on: May 27, 2017, 08:41:13 AM »
I shudder to think of Ukraine, a country in partial collapse (war, inflation) maintaining nuclear reactors.

16
Arctic sea ice / Re: The 2017 melting season
« on: May 26, 2017, 11:08:01 PM »
It should also be noted that North American volume has nosedived from way above average to normal this month. While this is hardly unprecedented, the sheer cliff we have seen will amount to ~700KM3 of volume by the end of the month. Seasonal discharge is normally quite slower, and also happens earlier in the season than this year in most years, so this will have some substantial impact on the NATL, or perhaps already is, given how cold SSTs are off Quebec/Newfoundland (and the implications on land were clear given the massive floods we saw in Quebec). How much more volume will it take before the impacts escalate even further, and how much farther down the line til that happens? It could feasibly occur next melt season...

What was the volume lost by Lake Agassiz during discharge?
Interesting question in itself though OT here, so I'll keep it short. It seems the answer is several thousands of km3, all discharging in the same direction, as opposed to 700 km3 over a very large area discharging in several directions and partially seeping into the ground. One paper I've found, https://pubs.er.usgs.gov/publication/70032297, provides modeled constraints on Lake Agassiz discharge of 1600 km3 - 9500 km3 through the St. Lawrence Estuary. So no, I doubt the snowmelt will escalate impacts on this or next melt season.

17
Arctic sea ice / Re: Latest PIOMAS update (April)
« on: May 26, 2017, 02:10:30 PM »
Eyeballing the numbers for the hundredth time, I would hazard the following guesses regarding upper volume limits, based on past performance and unreliable gut feeling:
April 20.800
May 19.800
June 15.800 (still a record though barely)
In terms of probability I wouldn't be surprised to see lower numbers, even much lower, but I would be surprised to see higher numbers.
Looking at past years and their numbers, and using my crystal Excel ball, I would hazard an estimate that a 19.4 volume on day 142 will result in a ~19.8 May monthly number.
If true, and as this coincides with my "upper volume limit" for May, I'd say it's still within the historical norm but rather poor. Not what you'd expect from a record year, though I still expect 2017 to be a record year with good probability.
A regional analysis quantifying the volume in Barents/Greenland/Baffin, Bering/Okhotsk, and the rest of the Arctic, compared to previous months and years, could help shed more light on 2017's prospects. Any tips on how to go about calculating these numbers?

18
Arctic sea ice / Re: The 2017 melting season
« on: May 26, 2017, 01:49:57 PM »
F. Tnioli, I apologize if my comment came across as negative. It was not meant that way.

19
Arctic sea ice / Re: IJIS
« on: May 26, 2017, 11:26:11 AM »
I think a lot of export of MYI into the Atlantic side over the winter is keeping up extent now. It may hold for a while longer.

20
Arctic sea ice / Re: The 2017 melting season
« on: May 26, 2017, 09:52:40 AM »
Epiphyte this has been discussed upthread in the Nares Strait thread, yes this huge slab broke off the fast ice, but no it couldn't have been grounded as the water is far too deep in Kane Basin. The rotation probably ocurred due to the faster current on the Ellesmere side, plus maybe some reverse curreny or gyre on the Greenland side, plus some wind effects.
I wish its breakup could have been filmed up close.

21
Arctic sea ice / Re: The 2017 melting season
« on: May 25, 2017, 05:25:33 PM »
Many things are possible in theory with negligible probability. Not really worth discussing in my view. But if you wish, the only practical way at this time to jam Nares is for Petermann to calve and produce as ice island.

22
Arctic sea ice / Re: The 2017 melting season
« on: May 25, 2017, 01:42:55 PM »
Temps in Resolute, in the middle of the NW passage, have reached 0o.

23
Arctic sea ice / Re: Latest PIOMAS update (June)
« on: May 25, 2017, 07:44:41 AM »
Thank you Wipneus for your continual amazing work.

Finally it seems the slow extent declines and the low DMI temps are having some effect.

24
Consequences / Re: 2017 ENSO
« on: May 24, 2017, 10:00:30 PM »
Insane. Putting out one's eyes doesn't typically solve problems.

25
Arctic sea ice / Re: What the Buoys are telling
« on: May 24, 2017, 05:34:14 PM »
Finally a clear image

26
Arctic sea ice / Re: The 2017 melting season
« on: May 24, 2017, 02:31:50 PM »
Temps near the Beaufort/Mackenzie delta are forecast to reach a high 11-13o tomorrow.
https://www.yr.no/sted/Canada/Northwest_Territories/Tuktoyaktuk/
https://www.yr.no/sted/Canada/Northwest_Territories/Inuvik/

27
Arctic sea ice / Re: The 2017 melting season
« on: May 24, 2017, 07:44:23 AM »
Thank you VAK

28
Arctic sea ice / Re: Arctic Image of the Day
« on: May 23, 2017, 05:19:50 PM »
I believe temps have been slightly above 0 at times in the last few days

29
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: May 23, 2017, 05:17:51 PM »
Yesterday's DMI NOAA AVHRR image shows Smith Sound very nicely. I've annotated a screenshot.
Great image, thanks Tor

30
Arctic sea ice / Re: The 2017 melting season
« on: May 23, 2017, 07:21:34 AM »
A very strange year in terms of extent. One might expect lower extent at this time, considering the poor winter and the huge lead in PIOMAS numbers, but instead we are 7th on the IJIS rankings. On the other hand, digging into the numbers shows a huge positive anomaly in the Barents sea, and much higher than normal extent in the Greenland sea and Baffin bay. Altogether the Atlantic side explains the whole anomaly. As the Atlantic is export-based, this will all go to hell at some point, but I'm sure current numbers have caused some raised eyebrows.

31
Here's a graph of measured CO2 levels at Mauna Loa from January 2013 through April 2017.

This data has been adjusted (by Scripps) to take out seasonal variation.




As you can see there's a flattening that has happened over the last six months.  I am not saying that CO2 has peaked.  There have been other periods where CO2 levels did not rise for a few months and then resumed climbing.  But it's worth keeping a close eye on for awhile. 

A guy can hope....

To be honest, this graph is not showing a flattening but a reverting from above-trend to trend. Still better than nothing of course.
But in general do keep up with focusing on the optimistic side. The main health effect of climate change (and many other long-term trends) is depression, and good news tend to get lost in that.

32
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: May 22, 2017, 07:27:28 AM »
Agreed. It is fun watching, and even educational when such a large piece of (first-year) fast ice crumbles at first contact without offering any resistance.

33
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: May 22, 2017, 12:49:25 AM »
Regardless of the (interesting) details, this thing is not going to plug Kane Basin. The way is open and will stay open until the end of the year.

34
Policy and solutions / Re: Oil and Gas Issues
« on: May 20, 2017, 06:43:34 AM »
Yay! Now we don't need to wait for the methane gun to fire - we can pull the trigger ourselves :o

35
Am I the only one confused by Bob's chart showing CH4 rather than CO2?

36
Consequences / Re: Sea Level Rise and Social Cost of Carbon
« on: May 19, 2017, 07:49:32 AM »
What do the column labels mean (50, 17-83, 5-95, 1-99, 99.9)?
Probability ranges.
Edit: Actually explained at the bottom of the table.

37
Arctic sea ice / Re: Stupid Questions :o
« on: May 18, 2017, 11:58:50 PM »
In the main thread a lot of people are getting excited about Nares "Export". But Baffin Bay is entirely frozen over. So why is it significant that ice is getting exported into more ice... more than any other Polynya opening up?
Ice in Baffin Bay reaches near-zero extent in August, more or less regardless of its initial condition. However, ice in the CAB, especially in the Lincoln Sea, can easily survive the summer, especially if it is thick.
So when Nares exports thick ice from the Lincoln Sea to Baffin, the CAB loses a potential summer-surviving asset, while Baffin gains basically nothing.
By the way, Baffin is not entirely frozen over at this time. It is currently about 200k km2 below its peak winter extent of 1.2 million km2.

38
Arctic sea ice / Re: The 2017 melting season
« on: May 18, 2017, 05:30:24 PM »
TB - Wipneus tracks grpahs or Arctic Basin area and extent, which excludes all peripheral seas but includes the seas adjacent to the CAB. I think this is what you are asking for.
Arctic Basin Extent
Arctic Basin Area
There are also direct-view links which I'm having trouble locating just now.

39
Consequences / Re: Where have all the Insects gone?
« on: May 18, 2017, 07:18:06 AM »
Wow. Human stupidity at its finest.

40
Arctic sea ice / Re: The 2017 melting season
« on: May 18, 2017, 06:30:10 AM »
I saw this surprising chart on Jim's site. I didn't think 2017 was tracking 2016 in this region, was quite sure it was lagging.

41
Policy and solutions / Re: James Hansen loves nuclear power
« on: May 17, 2017, 07:01:54 PM »
I'm not sure what Hansen's current opinion is, considering recent advances in wind and solar. But in any case maybe it would be best to change the subject to simply "Nuclear Power"?

42
Greenland and Arctic Circle / Re: The Nares Strait thread
« on: May 16, 2017, 08:43:13 PM »
The big slab in Kane basin has completed a 180 degree turn, and is now poised for head-first birth into Baffin bay.

43
Arctic sea ice / Re: The 2017 melting season
« on: May 16, 2017, 08:39:44 PM »
Hycom forecast is showing the thick ice off Ellesmere/Greenland coasts cracking and moving away again in a few days.

44
Arctic sea ice / Re: Stupid Questions :o
« on: May 16, 2017, 06:46:33 PM »
Rikw, a lot of it is the positive feedback between the NAD and sea ice. The drift both brings heat and prevents ice from forming. The north Atlantic/Barents is the only ice free area at high arctic latitudes. So when spring comes, all insolation is absorbed and temps can go up.
In Hudson Bay, ice forms and stays for 6 months, reflecting the sun and absorbing any local heat into ice melting.
Add to that the isolation of the bay which reduces waves, amd the lower salinity which promotes freezing, and probably some more items.

45
Arctic sea ice / Re: The 2017 melting season
« on: May 16, 2017, 05:17:36 PM »
Any idea how Nares compares with Fram on volume basis?
Looks like Nares export (on any measure) will be unusually large this year, owing to lack of arch formation.

Looking at the export over the last couple of days at start of the Robeson Channel (see gif) I estimate about 500 km^2 exported per day (each of the big rectangular blocks are around 20k x 10k). If the ice is 2m thick that is about 1 km^3 per day.

Assuming that we have an additional 2 month's flow through Nares compared to previous years, that is an additional 60 km^3 lost which is, very roughly, about 2-3% of the total ice volume in September.

So it's not very significant; but could make an impact in the thickest area.
bairgon, thanks for the analysis. I think these floes are suposedly closer to 4m thick than to 2m thick, so maybe it's double the volume exported.

46
Arctic sea ice / Re: IJIS
« on: May 15, 2017, 08:18:36 PM »
120k in two days.

47
Arctic sea ice / Re: The 2017 melting season
« on: May 15, 2017, 06:22:28 AM »
vigilius thanks for the animation. It's been refreezing over and over, until it stopped a few days ago - an important phase change. Now area can start dropping with continued movement.

48
Arctic sea ice / Re: Stupid Questions :o
« on: May 14, 2017, 03:44:41 PM »
CB, I too believe H's statement was totally false so thank for the rebuttal. But if continued this should be taken up in one of the population threads.

49
The rest / Re: How to secure internet ?
« on: May 14, 2017, 04:52:41 AM »
So do we blame the lame at Microsoft for building vulnerable machines, or the evil doers at the NSA for developing such evil software, or the evil dunces in the intelligence community for releasing this into the wild.
Decisions Decisions Decisions
Terry
Machines will always be full of backdoors and loopholes, and hackers will always try to profit from that. Having a government body do the heavylifting development is quite gross, though this might be more common than naively expected.
There's a couple of brilliant books by Vernor Vinge dealing with these backdoors among other things.

50
Greenland and Arctic Circle / Re: What's new in Greenland?
« on: May 14, 2017, 04:44:11 AM »
Thanks oren :) I was thinking that water drainage through moulins might cause heating of the ice sheet from below leading to destabilisation, in comparison to water that drained straight into the sea.
You are indeed right AFAIK.

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