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Messages - Bruce

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101
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: June 30, 2014, 06:39:29 PM »
Does anyone else think there may be a dramatic slowing in ice loss in the next week or two?
I tend to agree. The Kara isn't doing anything. The ice drift maps indicate increased flow through the Fram, so extent and area there could increase. Baffin is about done, and Hudson will be soon. If the ice in the ESS breaks up, extent could increase there, too.

On the flip side, the Beaufort and Chukchi look like they're going to open up more. The Laptev looks to keep opening up, and possibly the ESS, too (if the above break up doesn't inflate the numbers). It doesn't seem to want to warm up in the CAB, so major losses there seem a ways off.

Then again, things could warm up, winds could shift, and we could see big drops everywhere.

102
Arctic sea ice / Re: The 2014 Melting Season
« on: June 30, 2014, 04:40:20 PM »

Aside from it's job holding back the Greenland glaciers, doesn't the ice in the strait hold back a fair bit of the thickest, oldest MYI in the CAB?

I used to think that too that sea ice holds back glaciers like Petermann, but then realized the glacier is several hundreds of metres thick, whereas the sea ice is at most 5 metres thick.
True, now that it's just sea ice. But in a well-frozen arctic, that thick glacial ice would extend much further down the fjords, buttressing the glaciers and choking the strait with thick glacial ice. Now, as the outlets have melted, the thick ice is more easily flushed out, the glaciers calve off and float away, their grounding lines recede, and the buttressing gets weaker and weaker.

The melting process works from the other direction, too: as the surface of the ice sheet and glaciers melt, the meltwater runs through fissures in the ice to the rock interface, lubricating and speeding the flow. So not only is there less friction holding the glaciers back, the glacier is pushing harder to get out.

103
Arctic sea ice / Re: The 2014 Melting Season
« on: June 30, 2014, 07:27:03 AM »
I don't think the Earth is warm enough to melt out the arctic yet and it may be decades before it happens.
Friv,
I don't think 100% of the ice has to melt, any more than the arctic has to become the Caribbean, to make this a done deal. Once the ice hits 20, 15, 10 percent of the former ice cap, it's over; the proverbial fat lady has sung.

I used to think that that day would look like a dense pack of MYI desperately clinging to the CAA, holding out in it's last redoubt against the angry sea. But as my semi-tongue-in-cheek "big crack reports" suggest, I now believe that when we next get to that point, the whole thing will probably break off and disintegrate. We'll be left with a few stubborn floes wandering around a big empty ocean.

104
Arctic sea ice / Re: Records and oddities
« on: June 30, 2014, 06:33:07 AM »
It's NE of Resolute and Cornwallis Island.  That hole has been there since early June.
It was there last year and 2012, too. The ones nearby, as well. Don't know about earlier years.

There's something about that spot. Maybe a geothermal vent? Maybe a spot where currents and ocean floor topography conspire to drive an upwelling of warm, deeper water? An underwater base for space aliens?

105
Arctic sea ice / Re: The 2014 Melting Season
« on: June 30, 2014, 06:22:47 AM »
Hi Terry,
Thanks. That's a lot of ice for a narrow channel -- and if the ice fragments like it has in across a lot of the arctic, the amount could go up (even if the proportion doesn't).

I agree with you about 2012 but, as I said recently, 2013 was significant too. It was well on its way to breaking records when the conditions changed at the end of the season, and its numbers ended up unremarkable (for the new normal). But I believe that it did a lot of damage that didn't show up until now (though the warm winter had its effect, too.) We're seeing a lot of early melt this year, despite the relatively benign weather. If we get a couple of weeks of really melt-worthy weather, it seems like the whole thing is going to fall apart (and what are the odds that we won't get a couple of weeks over the next two months? It could happen but, as you say, that just puts things off for a year or two.)

It seems like a lot of people here sense it. I'm new to this forum, but I've been following the cryosphere closely for a few years. Things just feel different now. Like we've entered the terminal phase of the death spiral. We all know now that it is inevitable; it's just a matter of when, not if.

It's tragic. The north used to be a place of unspoiled wilderness. A place where nature still thrived, mostly unspoiled by civilization. Now we've killed it without even trying. What does that say about us and our future?

106
Arctic sea ice / Re: The 2014 Melting Season
« on: June 30, 2014, 02:58:07 AM »
Big crack report, June 29 edition: The big crack is turning into something else. In the upper left of the image, strands are branching off of the main crack, and shredding -- absolutely shredding -- the ice. From the midpoint of the image down, several en echelon strands have formed, and the older branch has opened up. The small crack north of Greenland (second pic) has opened up since yesterday.

It doesn't seem like the even the MYI has much strength to it. One good storm and we're going to see the world's biggest slushie (kelp flavored).

107
Arctic sea ice / Re: The 2014 Melting Season
« on: June 30, 2014, 02:35:59 AM »
It looks like Nares ice is disintergrating:
Yeah, I saw that little crack appear way up channel a day or so ago, but I never expected all the ice in-between to just explode like that.

Aside from it's job holding back the Greenland glaciers, doesn't the ice in the strait hold back a fair bit of the thickest, oldest MYI in the CAB?

108
Arctic sea ice / Re: The 2014 Melting Season
« on: June 29, 2014, 06:26:00 PM »
Help me out folks How is 2010 so  much lower?

 2010 is roughly -900K  below 2014 in that coparison
Look at the whole stretch from Greenland to Svalbard to FJL to NZ and into the Kara -- 2014 ice is pushed much further south that 2010. The Beaufort was more open in 2010, too. I don't know the numbers, but maybe that makes up for the areas where 2014 has less than 2010.

109
Arctic sea ice / Re: The 2014 Melting Season
« on: June 29, 2014, 01:31:41 AM »
Our little crack is taking on more impressive dimensions, and seems to have spawned a copycat that also curves north. And in the second photo, a "hairline" crack along the north coast of Greenland. A few more days at this rate, and this thing is going to turn into an event.

110
Arctic sea ice / Re: The 2014 Melting Season
« on: June 28, 2014, 04:45:44 PM »
It could be that this situation, when it lasts longer, will lower albedo rapidly and thus put the season on a not much expected path to strong melt. At least, my expectations.
You mean albedo changes kind of like this?  ;)

111
Arctic sea ice / Re: The 2014 Melting Season
« on: June 28, 2014, 05:59:20 AM »
The smoke from the fires in Canada, which for the past few days was streaming toward Hudson Bay, has decided to take a break and now seems to be meandering over toward the CAA. Because, hey, it can't get any worse, right?

(Pics are from 6/25, 6/26, and 6/27.)

112
Arctic sea ice / Re: The 2014 Melting Season
« on: June 27, 2014, 05:01:21 PM »
Thanks, BFTV and JayW -- the explanations are much appreciated.

Frivolous -- That depth chart was fascinating; I had no idea that the whole Siberian shelf was so shallow. That kind of water can warm up quickly. (You can also get light all the way to the bottom. I wonder if the scuba diving is any good?)

I posted this pic over on Wipneus' thread, but I'll repost here. It's the first good shot we've seen of the Kara in a while. Judge the ice for yourselves.

113
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: June 27, 2014, 04:30:21 PM »
Delta and concentration maps of Kara. There is a lot of high concentration ice in the region left, so I doubt if the decline can keep up. But who knows?
I think the high concentration is an illusion of the instruments. Look at the bottom half of the Kara -- the concentration maps show nearly 100% ice, but that's not 100% ice.

114
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: June 27, 2014, 04:23:58 PM »
There is still an apparent lack of low concentration areas within the main pack (indicating ponding), though, in the 2013 comparison one should take note of the prefound lack of blue shades on the Pacific side.
Ponding to start tomorrow:

115
Arctic sea ice / Re: The 2014 Melting Season
« on: June 27, 2014, 06:56:11 AM »

I integrated only the area for the whole N Hemisphere that had mean temp below zero and for the period 11/05 to 23/06. So it works as a proxy for 'temperature melt-conductiveness'. That's great English, isn't it :P?
It doesn't tell anything about the intensity of that conduc...you know what. So it is a crude assessment.
Werther,
I've been thinking about your plot. I agree that integrating only < 0 through the winter months doesn't take into account the intensity of the cold. It would be interesting to use a baseline for each grid point for each day using an average over as many years as you have, and then integrate the product of the anomaly * area (maybe normalized by total area). That could give some idea of the "stored potential" (i.e., how much (relative) energy it would take to melt the accumulated ice). I think warmer winters have as much to do with the melting of the Arctic ice as warmer summers -- maybe more. And I don't thing volume or area or extent tell the whole story; there's a quality to the ice that has changed. I think we're all seeing it, but we don't really have a way to quantify it.

116
Arctic sea ice / Re: The 2014 Melting Season
« on: June 27, 2014, 06:37:01 AM »
that crack is similar to what the HYCOM thickness forecast is predicting.

look what happens to the most easterly chunk that breaks away in the forecast!
Yeah, it just disintegrates. That's a great animation. It looks like these current conditions continue for a few days. It'll be interesting to see if that crack opens up.

The figure shows some detail of another thing I'm watching: when do the Beaufort and Chukchi join up? Once that happens, there's not much anchoring the ice. Looks like it could happen late next week.

117
Arctic sea ice / Re: The 2014 Melting Season
« on: June 27, 2014, 01:35:08 AM »
Wipneus pointed out this feature in his home brew thread, but I thought I'd update with today's image. It's a pretty impressive crack. It's starting to curve north, so it may not connect up with the weak spot north of Greenland (indicated at the bottom right of the picture), but if the current conditions hold, it looks like a very, very big chunk of ice might go wandering off. Not much to stop it -- everywhere around it there's big polnyas or highly fragmented ice.


118
Arctic sea ice / Re: The 2014 Melting Season
« on: June 27, 2014, 01:21:52 AM »
Frivolous, can you explain your final plot (animation)? I get that the white contours are isobars (I think), but what are the colored contours? Temperature? If so, what is the scale? The units on the scalebar don't make a lot of sense to me.

Thanks.

119
Arctic sea ice / Re: The 2014 Melting Season
« on: June 26, 2014, 05:35:05 PM »
Of course I've been contemplating this. There are many aspects. I'd be honoured to hear any opinions.

This is very interesting, but I don't think I understand the final graph. Did you integrate the temperature from the previous plot over area (i.e., Integral(Temp * dA))? Did you then normalize by something? Else, why are the units on the vertical axis in the 10K range -- shouldn't they be ~ 10e6km^2 * 273K = 2.73e9?

Oh, wait, maybe I get it -- did you integrate only the area that was below freezing for the entire time window?

120
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: June 26, 2014, 04:37:32 PM »
Sequence of the ice cover in the Kara Sea. Like we saw last year the melt will have to be in situ. If there will remain any stubborn ice remains to be seen, but I don't think so: the mobility is from edge to edge.
It's interesting to watch the ice in the rivers and inlets progressively melting to the north. I think that gives us some indication of when the serious melting will hit the Kara. Maybe about a week.

121
Arctic sea ice / Re: Home brew AMSR2 extent & area calculation
« on: June 26, 2014, 04:35:00 PM »
In this contrast (extreme) enhanced image a crack is seen developing just north of the CAA islands. I am loosing it at the entrance to the Nares Strait, but is suggests it will run all the way to a similar crack north of Greenland.
Have we ever seen the whole cap pull away from the CAA and Greenland (creating a sort of NNW passage)? I don't recall it, but there doesn't seem to be anything preventing it: the ice on the other side of the basin is either gone or heavily fragmented.

122
Arctic sea ice / Re: The 2014 Melting Season
« on: June 26, 2014, 04:11:50 AM »
NW Greenland. Look at what passes for sea ice in the Baffin Bay. Now look at edges of the ice sheet. Melty.

123
Arctic sea ice / Re: The 2014 Melting Season
« on: June 26, 2014, 04:05:23 AM »
It's weird, you can just see the areas that are going to melt (if it gets just a little warmer...)

124
Arctic sea ice / Re: The 2014 Melting Season
« on: June 26, 2014, 02:22:47 AM »
The ability of Arctic climate to buffer short timescale extremes of temperature heat may be at an end.
Well put. Without a couple of cool summers and very cold winters in a row -- which could rebuild the ice, at least temporarily -- we're losing an important climatic thermostat.

All the snow is gone early in the season now. What happens when most of the ice is gone by the end of June? Where does all that heat go? What sort of chain reaction might we be inadvertently initiating?

Personally, I'm not a big fan of uncontrolled experiments that have the power to wreak havoc on the planetary environment.

125
Arctic sea ice / Re: The 2014 Melting Season
« on: June 25, 2014, 01:36:10 AM »
Does this picture bother anyone but me? It is the north of Greenland. I refer specifically to the areas marked with arrows. They all seem very eager to melt. And they have a job to do buttressing some big honking outlet glaciers that drain the ice sheet. When they go away, or are very weak, the glaciers can do whatever they want. And as sea level rises, the grounding lines move back, and the warm water lubes things up, what the glaciers want to do is go swimming the ocean. Which adds to sea level rise, blah, blah, blah.

Why are those fjords, which are so far north, so eager to melt? (It looks like they did quite extensively in 2012, but less so in 2013.)

How long will those ice streams hold up if their dams melt every year?

What about that big guy to the West (is that the Peterman?)? What if he falls apart and dives in? Yikes!

126
Arctic sea ice / Re: The 2014 Melting Season
« on: June 25, 2014, 01:09:39 AM »
As a lot depends on weather and the quality of the ice within the CAB (which is probably worse than '12 because the trend is always down) [...]
This, of course, is a key point. Every year there is more heat in the oceans (this May's SST were apparently the warmest (May) ever recorded). The permafrost is warmer, so the runoff is warmer. The CO2 is higher. There are wildfires dumping soot, making the snow less reflective. Etc. What chance does the ice have against an assault like that? None. The winters are a lot warmer now, so the ice can't even rebuild.


127
Arctic sea ice / Re: The 2014 Melting Season
« on: June 24, 2014, 06:14:27 AM »
The Beaufort has gotten crushed.
Yeah, and look what's left. Might as well be ice cubes floating in the Caribbean.

http://rapidfire.sci.gsfc.nasa.gov/imagery/subsets/?subset=Arctic_r05c02.2014174.terra

128
Arctic sea ice / Re: The 2014 Melting Season
« on: June 24, 2014, 01:05:49 AM »
This might be the wrong thread for my question, but does anyone have any thoughts about today's earthquake (http://www.washingtonpost.com/news/post-nation/wp/2014/06/23/large-earthquake-near-alaska-triggers-tsunami-warning/) being related to uplift caused by melting ice, and will we be able to see any visible effects of the earthquake on the remaining pack ice?
Thanks!
Hey, a question in my field! Big earthquakes in the Aleutians are generally subduction events -- either a thrust event at the interface of the subducting and overriding plate, or a normal event within the subducting slab. Sometimes there is an oblique component. They're a quite common occurrence (geologically), due to tectonic activity, and almost certainly have nothing to do with melting ice.

The most likely way for the ice to be affected by an earthquake is via a tsunami. But the ice cap will largely be protected from any tsunami going its way by the narrowness of the Bering Strait. Even without the strait, however, tsunamis in the open ocean are very broad and low amplitude. If you were in a boat you'd be very unlikely to notice one going by. It's only when they get close to shore that they "bunch up" and create the large amplitude waves that do so much damage. So if a tsunami did go through the Arctic Ocean, only the near-shore ice would be likely to get chewed up.

129
Arctic sea ice / Re: The 2014 Melting Season
« on: June 24, 2014, 12:46:50 AM »
Quote
The ice looks still to be fragmented all the way to the Pole

Is it possible that some clever person might figure out a way to put an objective number to that fragmentation?  Perhaps there's someway to generate at least rough numbers for the missing metric - the quality of the remaining ice.
That'd be fun, too. If you had good images you could compute the area and circumference of all the ice chunks. Use thickness data to get a surface to volume ratio (or maybe just stick with circumference/area). Maybe divide it by the same metric computed for an idealized ice cap. 1 = happy ice, anything greater gives some idea of how vulnerable the ice is.

Hmm, it needs some work. Maybe need to work the ratio of ice to water in there, too. But I think there's something in there somewhere.


130
Arctic sea ice / Re: The 2014 Melting Season
« on: June 24, 2014, 12:20:56 AM »
What isn't measured, isn't happening...???

True dat. I wish I had the time. I'd take a shot at it: the concentration data should give a good approximation of the amount of ice moving through some arbitrary lines across the straits. Thickness would be a bigger guess, but there's at least some data floating (heh) around.

I doubt the number would be big, but it would be nice to have a ballpark estimate for the past few years.

131
Arctic sea ice / Re: The 2014 Melting Season
« on: June 23, 2014, 09:50:59 PM »
Try looking at June 30 2012

I reckon you need to go to July 2nd 2012 before you can see much through the clouds. As you say, things looked a lot more solid two years ago than they do today.


2013 is totally underrated in terms of its long range effects. 2012 melted a lot of ice, but 2013 *destroyed* the pack ice. Yeah, the weather turned at the end of the season so it looked like an uneventful year, but the damage was already done. So far, this year looks like 2013, only with the whole cap shoved over toward Svalbard. It's still highly fractured, but not as spread out as last year. But that only means a steady wind can blow more ice into the north Atlantic to melt -- the ice has no structural integrity to hold it back.

Things have changed. Even "normal" weather is going to lead to very low end-of-season ice. Maybe not record low, but top (bottom?) five kind of low. 2012 and 2013 were a one-two punch that I doubt the arctic will ever recover from. Unless we get a couple of very cold years in a row (and, let's face it, what are the odds of that?), we've only got a couple of years until we're betting on what day in August we hit 95% melt. Depressing.

132
Arctic sea ice / Re: The 2014 Melting Season
« on: June 22, 2014, 08:13:29 PM »
Hi all,
Is anybody tracking ice flux through the Fram Strait, between Svalbard and FJL, etc. It seems doable -- the daily images have plenty of resolution.

It would be interesting to know how this parameter has varied over the past couple of decades (assuming there's that much data.) I suspect it's a bigger factor these days than it was twenty years ago when the ice was thicker and less fragmented, but it would be nice to have some data.

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