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Jai: And if the curve continues exponential growth through 2060 (12 doublings) it'll be many times that. If it continues until 2100, the Earth will collapse into a black hole made of water *
My point is that melting the entire Greenland ice sheet would cause about 7 metres of sea level rise. Unconstrained extrapolation of exponentials is insanity.
* Well, maybe not. I wonder how long it would take?
Pinpointing the minimum
UPDATE September 16th: Given another uptick and the current weather forecast, I'm ready to call the minimum for IJIS SIE V1 on September 12th at 5,000,313 km2. Apparently the high was too big and the pressure gradient too low to prolong things (see below). --- This blog post should perhaps ha...
... and when it turns out to be one of those weather systems that has little or no effect on the melt, or even apparently increases extent, it's the most spectacular own goal in the history of ever. Not to mention the fact that there are only half a dozen or so idiots worth mentioning, so the list runs out in a couple of years and you have to start reusing names.
The Naming of Arctic Cyclones
The Arctic is about to welcome another big cyclone. Though probably not as large, intense and long-lasting as last year's Great Arctic Cyclone, it is rather intruiging to see a cyclone of similar magnitude occur so soon after the last one. It makes one wonder whether the Arctic will be seeing mo...
For me, about 5 years of experience following Arctic sea ice. I don't get deeply into the mathematics or do any modelling myself, so I count as a 1 in your system.
However, I think you're missing something here, which is that not all mathematicians, models and arguments are equal. I am a professional scientist, my main field being molecular biology, and the reason I don't do the modelling myself is because I know the limits of my ability. Regrettably, I have seen several extensive "modelling" posts on this blog and others by those with no such self-awareness, proposing quite unphysical models.
The Dunning-Kruger effect applies to fake-skeptics and alarmists alike.
Crowd-Source Prediction of Mean September Sea Ice Extent (July update)
Each June, July and August, the SEARCH Sea Ice Outlook (SIO) collects predictions for the mean extent of Arctic sea ice in September. These predictions come mainly from scientists but also some other people, drawing on a variety of modeling, statistical or subjective methods that each contributo...
Wayne: Thanks for clarifying that you weren't talking about net melting - that makes more sense now. I have no idea how well the buoys detect the active thaw/refreeze zone at the base of the ice.
P-maker: You're a loony. Buckets and spades? Even leaving aside the sheer implausibility of the scale of it (work out how much you can reasonably expect a man to shovel in a day, what area that equates to, and how many men you'd need to cover the ablation zone), it's a totally wrong-headed endeavour.
What will you do with the snow you scoop up? You can't just move it to a different part of Greenland, you know. That wouldn't achieve anything. You'd have to take it somewhere else, God knows how many gazillion tons of it. And then refrigerate it forever, using God knows how much energy to do so, because if you just let it melt, that itself constitutes a significant mass loss off the sheet. And what of the heat generated by the men on the ice sheet, and the machines required to cart the snow away?
"Just sweep up the dirty snow" my sweet aunt Fanny. Honestly, I'd expect more sense from any seven year old.
Greenland “snow drought” spells trouble
Hat-tip to HeisenIceBerg over on the Forum. I think most of us vividly remember last year's events on and around Greenland. It started with albedo going down considerably, causing widespread melt - at one point involving practically all of the ice sheet's surface - ending in a record mass loss...
To make the same point another way: the mean and the median of the crowd-sourced estimate are both currently around 2.9, which means that Hydrologist is less of an outlier than the folks predicting zero.
Crowd-Source Prediction of Minimum Arctic Sea Ice
How does the collective wisdom of Arctic Sea Ice blog participants compare with expert scientific analysis in forecasting the September sea ice extent? This question seems worth exploring with a crowd-source experiment. You are all invited to submit, as comments to this post, your best guess for...
No need to throw out data, it's irrelevant given how many estimates are already in. Let's say he's 4 million above the consensus (which he isn't). With ~100 guesses already in, this one wild guess will only skew the average up by 0.04 M km^2, which is completely irrelevant.
If you look at the graph, it's pretty symmetrical: the tail at ~5M balances the tail at zero. Both are equally unrealistic.
Crowd-Source Prediction of Minimum Arctic Sea Ice
How does the collective wisdom of Arctic Sea Ice blog participants compare with expert scientific analysis in forecasting the September sea ice extent? This question seems worth exploring with a crowd-source experiment. You are all invited to submit, as comments to this post, your best guess for...
Hi Wayne - could you let us know how you are observing this underside melt, and where you're based? This melt doesn't seem to be visible to any of the sonar buoys across the Arctic.
http://imb.crrel.usace.army.mil/newdata.htm
All of these show that the ice is is still thickening slowly, including 2013A which is quite far south within the Canadian Archipelago. The only exception is 2012L, which is in ~3.4 metre thick ice and so further thickening by congelation is not really expected.
Greenland “snow drought” spells trouble
Hat-tip to HeisenIceBerg over on the Forum. I think most of us vividly remember last year's events on and around Greenland. It started with albedo going down considerably, causing widespread melt - at one point involving practically all of the ice sheet's surface - ending in a record mass loss...
~4 million. Predicting this far out is a crap-shoot though, I'm just going for somewhere between 2012 and 2007 on the grounds that we have an accelerating downward trend, but two record years in a row seems unlikely.
Crowd-Source Prediction of Minimum Arctic Sea Ice
How does the collective wisdom of Arctic Sea Ice blog participants compare with expert scientific analysis in forecasting the September sea ice extent? This question seems worth exploring with a crowd-source experiment. You are all invited to submit, as comments to this post, your best guess for...
we can pull out the properties of the exact pixel corresponding to the buoy.
No you can't. You can pull out the properties of maybe the 100mx100m area immediately around the buoy, most likely substantially less. This is an insignificant fraction of the corresponding pixel.
Perception of the Arctic
There was a time, not too long ago, when I didn't know the Arctic existed. Sure, I knew there was a North Pole and that it was cold there, but somehow I always thought that the Arctic and the Antarctic were the same thing, that someone had forgotten to add the Ant-. And of course, polar bears ...
Just to whet your appetite, buoy 2012L is not reporting a single centimeter of ice gain or loss this whole time. It's stayed 3.35m thick. If this holds for a lot of other buoys, I'm planning to hit the trash button on a whole lot of model papers, products and posts.
Why would you do that? It's well known that once you get past about 2 metres thick, ice doesn't thicken much more by accretion. Instead it thickens by ridging, over-riding and slabbing. If any of that happened to the ice the buoy was embedded in, it would destroy the buoy! It's therefore not surprising that none of the buoys are able to observe it.
The models operate at a much coarser resolution: each pixel represents the average thickness across many square miles of ice, and thus averages together the ridges and the areas between the ridges.
Perception of the Arctic
There was a time, not too long ago, when I didn't know the Arctic existed. Sure, I knew there was a North Pole and that it was cold there, but somehow I always thought that the Arctic and the Antarctic were the same thing, that someone had forgotten to add the Ant-. And of course, polar bears ...
Aircraft contrail.
Met Office looks into Arctic link to weird weather
Commenter Steve Bloom always links to interesting stuff (if the new spam filter system lets him). This time it's about an article on the ITV website (and in the sensationalist Daily Mail) that links Arctic warming and sea ice loss to the late outburst of weird winter weather in the UK and the re...
Lodger: That's not how the averaging works. It's not that they get a readout once each day and then average two successive days together. Rather, they take all the swaths from the last 48 hours, combine that into one picture and then calculate the extent.
Some parts near the Pole will have been scanned dozens of times during that period, others will have been scanned only once - I don't think one day's data is quite enough to image the the whole Arctic, and even if scanned twice some parts will have been obscured by cloud in one or other of the scans. Moreover, the pattern of exactly which areas have been oversampled / undersampled on each day will vary from day to day. Trying to extract a "single day's worth" of data from the final product is absolutely futile endeavour, and would be meaningless even if you could do so.
On the move
When A-Team is not improving masterpiece paintings, he makes great animations. Here's yet another one, showing the speed with which the cracked ice pack in the Beaufort Sea has been moving in past weeks: The largest crack functions as a reference point. In the Arctic Sea Ice Forum I jokingly ...
Final pedant point: there is no "release of energy from the fragmentation of the meteor". Fragmenting a rock takes energy, as you'll appreciate if you've ever hit one with a hammer.
The energy source is the stored kinetic energy of the rock, which gets dumped into the upper atmosphere as heat energy and compression.
CryoSat-2 reveals major Arctic sea-ice loss
We knew that observations by the CryoSat-2 satellite were by and large confirming the modeled data from the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center, because of the recent publication in GRL of Laxon et al.'s CryoSat-2 estimates of Arctic sea i...
Putting it another way, "sonic booms" are (the sound caused by) a particular subset of "shockwaves". Your definition restricts it simply to being the bow waves from objects moving faster than sound. I'm using it to mean any shockwaves caused by objects moving faster than sound, including those caused by frictional/compressive heating of the atmosphere.
Wikipedia doesn't help: either of those definitions is technically valid. Either way, it's a bit of a sterile debate. Changing the words doesn't alter the physics, which we all agree on anyway!
CryoSat-2 reveals major Arctic sea-ice loss
We knew that observations by the CryoSat-2 satellite were by and large confirming the modeled data from the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center, because of the recent publication in GRL of Laxon et al.'s CryoSat-2 estimates of Arctic sea i...
I think we're at major league cross purposes here. I'm not denying that the object fragmented explosively, causing a shockwave. The point is that this is still simply a conversion of the kinetic energy of a moving object into sound/pressure waves, i.e. the same process involved in generating a "normal" sonic boom.
There was no extra input of energy (e.g. chemical or nuclear energy in a bomb, electrical energy in a thunderclap), just the kinetic energy of the incoming rock.
CryoSat-2 reveals major Arctic sea-ice loss
We knew that observations by the CryoSat-2 satellite were by and large confirming the modeled data from the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center, because of the recent publication in GRL of Laxon et al.'s CryoSat-2 estimates of Arctic sea i...
the shockwave wasn't due to sonic boom
This is meaningless. A sonic boom is a shockwave, and vice versa. It simply means that something is travelling faster than the speed of sound, and so the compression waves all stack up on top of each other.
In the case of an explosion, the thing travelling faster than sound is the expanding hot gases from the explosive reaction. In the case of an aircraft's sonic boom, it's the bow waves from the aircraft's movement. In the case of the meteor, the movement is sufficiently fast to heat the gas surrounding the bolide, so you get both processes going on.
CryoSat-2 reveals major Arctic sea-ice loss
We knew that observations by the CryoSat-2 satellite were by and large confirming the modeled data from the Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) at the Polar Science Center, because of the recent publication in GRL of Laxon et al.'s CryoSat-2 estimates of Arctic sea i...
You have to think of it in terms of ice cohorts.
2007 was a record summer melt, which means that a record amount of new 1st-year ice formed during the winter of 2007-2008. This ice became 2nd-year ice in winter of 2008-2009, 3rd-year ice the following year, and so on. Naively therefore one would expect a substantial increase in 5th year ice in December 2011.
However, this didn't come to pass. There are two reasons for this. Firstly 2008 was also a huge melt, so this cohort did particularly poorly in its first year. Secondly, this cohort also got slaughtered in summer 2010, and failed to mature from 3rd year to 4th year ice.
In contrast, the ice that formed during winter of 2008/2009 was followed by the comparatively weak 2009 summer melt: i.e. proportionally more of this cohort survived its first year, and has subsequently matured. It shows as a "bulge" of 2nd year ice in December 2009, 3rd year ice in December 2010, 4th year ice in December 2011 and now it has just tipped into the 5+ bracket.
Steven Goddard has been obsessively following this and touting it as a "recovery" of multi-year ice depite the fact that it's the only cohort of ice to show any improvement. All other brackets are down dramatically.
What I'd love to see would be a series of graphs showing the absolute area of each ice cohort from formation onwards.
Open Thread February 2013
The previous open thread has gotten full enough, so here's a new one. We might want to kick off with this animation made by commenter A-Team: His comment: Don't miss this -- it's happening right now, by the hour -- so head on over to 80N 150W. A huge fracture has been opening a bit east of B...
Sorry Al, but that plot of PIOMAS vs troposphere temperature is just linear regression in disguise, since the temperature itself also has a trend.
You might just as well plot PIOMAS against my house price and discover that ice volume will hit zero when the house price hits £350k (or whatever).
The real AR5 bombshell
The whole fake skeptic propaganda effort disguised as 'leak' is boring me to death, but of course it's interesting to have a sneak peek preview of the IPCC Fifth Assessment Report (AR5) and see what they will have to say about Arctic sea ice. Geoff Beacon from the Brussels Blog already had a g...
In fact, tell you what, why don't you tell us as soon as you have something that you can drop from 5 feet onto a frozen water butt, and have it drill through and measure the thickness.
Come on, time's a-wasting!
The real AR5 bombshell
The whole fake skeptic propaganda effort disguised as 'leak' is boring me to death, but of course it's interesting to have a sneak peek preview of the IPCC Fifth Assessment Report (AR5) and see what they will have to say about Arctic sea ice. Geoff Beacon from the Brussels Blog already had a g...
I propose herewith to invent cheap mass produced air droppable floating ice probes, which drill automatically a sensor stick through the ice and keep track and transmit ice & snow thickness, salinity, temperature, radiation balance. Then spray the ice sheet with thousands of them.
Wow! What an amazing idea! I wonder why nobody's thought of it before! Please tell us as soon as you have a working prototype!
The real AR5 bombshell
The whole fake skeptic propaganda effort disguised as 'leak' is boring me to death, but of course it's interesting to have a sneak peek preview of the IPCC Fifth Assessment Report (AR5) and see what they will have to say about Arctic sea ice. Geoff Beacon from the Brussels Blog already had a g...
P-maker: They are clearly open water, i.e. polynyas. They are far too dark to be melt pools. Melt pools over sea ice look greyish or blueish in visible wavelengths - you can see a margin of ponded sea ice all round the edge of the glacier tongue, which looks completely different to the polynyas.
It's grossly insulting to label work from peer-reviwed, pulished scientists as a "fairy tale" based on nothing more than your own boundless ignorance and gut feelings.
The quality of commentary on this blog really has taken a catastrophic downturn this year. I hope it clears up by next year or I'll just write it off like I do for YouTube and other such sinkholes.
Looking for winter weirdness 2
While the US East coast is preparing for an intensifying Sandy (Jeff Masters has all the info you could possibly want), Europe is being struck by a very early cold snap. According to German meteorologist Christoph Hartmann such early snows in Germany occur every 30 to 40 years (link).* Bulgar...
L1 libration point is unstable, so you can't use ordinary chaff - the radiation pressure from absorbing/reflecting light would push it out of the L1 orbit. You need to use a transparent sheet that refracts light in all directions ~equally. That cuts down the direct transmission (i.e. you shade the Earth) while keeping the radiation pressure to a manageable level (i.e. the shade stays put). Even then, you still need computer-controlled guidance to keep it in orbit.
You're not going to be able to manufacture something that specific from whatever randomly happens to be the composition of the asteroid you land on.
It basically boils down to the fact that trying to get something to stay at the L1 libration point is equivalent to balancing a pencil on the pointy end.
Arctic methane: Why the sea ice matters
Here's a video from the Arctic News blog, which is run by the people from AMEG (Arctic Methane Emergency Group). I'm not a big fan of geo-engineering, especially if it supports the continuation of business-as-usual, but as this video has some good speakers that dare speak of worst-case scenarios...
How about dredging the sea bottom? How energy intensive is that?
I have no idea, but I can tell you it takes a lot more energy to dredge up a cubic metre of gloop from the sea floor than it does to siphon off a cubic metre of water from the sea surface.
And you still have the same problem of where to put it. Filling Death Valley with seawater or with sea-bottom mud really doesn't make a lot of difference, from that perspective.
Arctic methane: Why the sea ice matters
Here's a video from the Arctic News blog, which is run by the people from AMEG (Arctic Methane Emergency Group). I'm not a big fan of geo-engineering, especially if it supports the continuation of business-as-usual, but as this video has some good speakers that dare speak of worst-case scenarios...
http://www.pnas.org/content/103/46/17184.full.pdf+html
Requires us to put 20 million tons of stuff into orbit, which in turn requires us to cut the cost of doing so by three orders of magnitude.
Oh, and the L1 libration point is unstable, so you can't just use chaff, you have to use spacecraft with onboard computer controls and adjustable elements so they can move themselves around by radiation pressure.
16 trillion of them.
Arctic methane: Why the sea ice matters
Here's a video from the Arctic News blog, which is run by the people from AMEG (Arctic Methane Emergency Group). I'm not a big fan of geo-engineering, especially if it supports the continuation of business-as-usual, but as this video has some good speakers that dare speak of worst-case scenarios...
Oh come on people, scale! Saying the ice will damp down waves in the surrounded area is like saying there are no waves in the Mediterranean because of the surrounding land. The size scale for wind/wave dynamics is smaller than a single pixel on satellite maps.
Bilateral freezing
It happened a while back, but it's one of those interesting details that make what's happening in the Arctic so unique. In August we saw something that hasn't been recorded before (not on that scale, that is): the detachment of large parts of the ice pack. In October the opposite happened. In...
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