tag:blogger.com,1999:blog-1367053740188758246.post7684915025324581022..comments2023-06-21T00:39:34.443-07:00Comments on Dosbat: A Sea Ice Free Arctic by 2020 (and maybe sooner).Chris Reynoldshttp://www.blogger.com/profile/16843133350978717556noreply@blogger.comBlogger21125tag:blogger.com,1999:blog-1367053740188758246.post-11871152682073166012012-10-02T11:18:42.976-07:002012-10-02T11:18:42.976-07:00Kevin,
Right, I've just read it, didn't m...Kevin,<br /><br />Right, I've just read it, didn't mean to. I just started and carried on to the end. <br /><br />It's hard going, there's a lot of detail there. With regards the AD it's possible that as Overland 2012 notes the GCM isn't picking up the factors driving the summer AD. <br /><br />However in any case, the paper states: "The SLP anomaly during the summer event is given by an elongated high pressure ridge over the European and Eurasian coast, connected to an anomalous inflow of warm air from the Nordic Seas into the Arctic ocean."<br /><br />That's not the summer configuration post 2007!<br /><br />The comment regarding BC amused me - that always seemed a rather minor issue. The albedo changes due to younger ice seem to wipe that issue off the table in terms of significance.<br /><br />Thanks for that paper. I clearly need to read it again when I'm not so tired.<br /><br />If you want to write posts for this blog you're welcome - you've got my email. But I can't help but wonder - why not start your own blog? IMO it's important to have as many blogs out there as possible to counter the denialist nutters.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-1748996019777045582012-10-01T15:32:19.008-07:002012-10-01T15:32:19.008-07:00Chris, there's a lengthy paper available for r...Chris, there's a lengthy paper available for reading and comment at Ocean Science Discussions - <a href="http://www.ocean-sci-discuss.net/9/2327/2012/osd-9-2327-2012.pdf" rel="nofollow">Arctic rapid sea ice loss events in regional coupled climate scenario experiments</a> by<br />R. Doscher and T. Koenigk.<br /><br />They examine 30 different RILEs found in their model runs and classify, compare, and contrast the processes behind them. I think you'll find corroboration for many of your insights. From the concluding summary:<br /><br /><i>The mechanisms for rapid ice loss we find here are predominantly related to atmospheric circulation and seasonal-to interannual memory build up in the ice thickness. We also tested the idea of possible upward transport of ocean heat by vertical mixing in response to reduced ice concentration. Such a process was not found in this model although observations indicate import of warm ocean water from the Pacific<br />Ocean (Woodgate, 2010) and proximate inclusion in vertical mixing. While those observed results are under discussion, we cannot expect to find them in the model due to to coarse resolution and insufficient Bering Strait inflow.</i>Kevin O'Neillhttps://www.blogger.com/profile/06692943768484857724noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-49029830352425858382012-09-27T08:44:00.706-07:002012-09-27T08:44:00.706-07:00I've given up with that individual. I struggle...I've given up with that individual. I struggle to see the difference from the denialists.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-20994013621421597702012-09-26T15:46:53.400-07:002012-09-26T15:46:53.400-07:00I must admit to being dumbfounded by someone that ...I must admit to being dumbfounded by someone that thinks weather forecasting is a science - and climate science is alchemy. He apparently doesn't realize that they are virtually one and the same. The difference of course being that short-range model output (weather) is obviously going to be more accurate than long-range model output (climate).<br /><br />Some people must think there's a team of meteorologists at ECMWF (for instance) that sit around each day looking at maps, radar images, perusing terabytes of observations and then decide what to put into their weather forecasts. <br /><br />Kevin O'Neillhttps://www.blogger.com/profile/06692943768484857724noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-40648434293630302162012-09-26T11:47:28.441-07:002012-09-26T11:47:28.441-07:00BTW, I see you're having fun over at Nevens. ;...BTW, I see you're having fun over at Nevens. ;)Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-78000410694737418522012-09-26T11:34:34.235-07:002012-09-26T11:34:34.235-07:00Kevin,
The reason I don't think that's su...Kevin,<br /><br />The reason I don't think that's such a significant factor any more is that the Beaufort Gyre flywheel has failed, is is no longer rotated and aged in the gyre before being dumped into the stream of the transpolar drift over the Lomonsov ridge, but is melted away most years in the Pacific sector open water.<br /><br />I did a post earlier this year disagreeing with someone's claiming to be able to predict the ice edge in September. The reason I gave was that they were picking up key features of all years' minima. One of these is the ice tongue that is seen in 2010 and 2011 , see <a href="http://igloo.atmos.uiuc.edu/cgi-bin/test/print.sh?fm=09&fd=01&fy=2010&sm=09&sd=01&sy=2011" rel="nofollow">here</a>, which is to the pacific side of the Lomonsov ridge. I think that the lack of surface melt they were seeing was due to thicker ice in that region - due to the bathymetric factor Nghiem outlines there.<br /><br />I accept the tendency for the Odden ice tongue to cling to Greenland's continental shelf, and the bathymetric effects on perennial ice in Beaufort. However I still think the biggest single factor is in the Atlantic sector due to the dropping of AW out of contact with the ice as it hits the edge of the abyss (I forget the name of that abyssal deep).<br /><br />Just looking at this year and 2007 shows, I think, an important lesson for future summers. Whatever recession there will be will come from the Pacific sector, not the Atlantic.<br /><br />Actually this Nghiem paper isn't the reason for my thoughts about the Atlantic sector - I find I only downloaded it earlier this summer. I've tied the Atlantic sector lack of recession to bathymetry for longer than that - puzzled.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-80249432937144716612012-09-25T16:35:37.202-07:002012-09-25T16:35:37.202-07:00Chris, I thought the take-away graf was this:
&q...Chris, I thought the take-away graf was this:<br /><br />"<i>The seafloor structures can dictate where perennial sea ice resides across the Arctic Ocean: over the deep basin off the continental shelf of the Laptev Sea, the Kara Sea, and Barents Sea, and over the continental shelf of the Beaufort Sea. This distribution of perennial sea ice is coincidentally located along the primary path of the Transpolar Drift. In strong Polar Express events driven by strong wind forcing supported the atmospheric dipole anomaly (Nghiem et al., 2007), an excessive transport of perennial sea ice out of the Arctic via the Fram Strait can results in massive ice loss since perennial ice is the older and thicker type of sea ice compared to first year or seasonal sea ice. While the Polar Express is driven by anomalous winds, the direction ofthe ice transport along the Transpolar Drift is not arbitrary as it is limited in the deep transpolar basins such as the Nansen Basin, and aligned along Lomonosov Ridge across the Arctic Ocean (Alkire et al., 2007). Such bathymetry control on the location of perennial sea ice sets up a condition conducive to an abrupt reduction of perennial sea ice, which in turn preconditions the large decrease of the total SIE during summer.</i>"<br /><br />The bathymetry is a double-edged sword: allowing the build-up of thicker ice, but then acting as a natural conduit for its rapid evacuation.Kevin O'Neillhttps://www.blogger.com/profile/06692943768484857724noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-57966781828486544602012-09-23T22:57:31.020-07:002012-09-23T22:57:31.020-07:00Thanks again Kevin.
Yes I've read the Nghiem ...Thanks again Kevin.<br /><br />Yes I've read the Nghiem paper - it's why I keep saying the Atlantic Water won't play much of a role in warming. That's because AW drops off the edge of the deep in Atlantic. I see it as a key player in the lack of retreat in the Atlantic sector.<br /><br />I'm less convinced about the strength of this bathymetric effect in the Siberian/Pacific Sectors because here the ice edge shows less of a tendency to be stalled at the bathymetric drop off into the abyss, you'll see that in Beaufort.<br /><br />I'm not convinced about the role of the Herald canyon - I'd been expecting seperate ice regions, with one broken off from the main pack (the first instance of this on such a scale IIRC) but my reasoning was due to wind speeds implied by pressure gradient.<br /><br />The AW issue is special due to the salinity of the Atlantic (denser than Arctic) and its warm temperatures. This doesn't apply to water warmed by insolation and AD driven flow through Bering - which starts off being native to the Artic. I still think insolation can cause a summer warm cap over the colder deep thus being largely immune to bathymetry. That's one peripheral reason I think we'll see a fast transition - bathymetry won't dictate a refuge region.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-57218328996966454032012-09-23T19:23:23.644-07:002012-09-23T19:23:23.644-07:00Chris, I think you'll find this interesting S...Chris, I think you'll find this interesting <a href="http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20120003985_2012004065.pdf" rel="nofollow">Seafloor Control On Sea Ice</a> by Son Nghiem. Jamie Morison has a slideshow highlighted in the NY Times on the same subject (<a href="http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&ved=0CCIQFjAA&url=http%3A%2F%2Fwww.slideshare.net%2FRevkin%2Fan-arctic-experts-view-of-the-great-ice-melt-of-2012&ei=q8FfUIXjErGA0AHe0oHADA&usg=AFQjCNHZ_m7_RrUoEb1cFYgbBusWR_GgTA&sig2=0lNin-0n4RIebLSorA2x-A" rel="nofollow">An Arctic Expert's View of the Great Ice melt of 2012</a>) and credits Nghiem for the idea.Kevin O'Neillhttps://www.blogger.com/profile/06692943768484857724noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-90812576029607318632012-09-23T12:36:20.889-07:002012-09-23T12:36:20.889-07:00Thanks a lot Chris! Just what I was after!Thanks a lot Chris! Just what I was after!Jon Dhttps://www.blogger.com/profile/15348915029836913496noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-34688725827951637402012-09-23T00:53:42.042-07:002012-09-23T00:53:42.042-07:00Jon,
The volume loss of 2010 virtually removed gr...Jon,<br /><br />The volume loss of 2010 virtually removed grid boxes reporting ice of over 3.5m thick from PIOMAS, sugesting that there is now a negligible amount of thick old ice in the Arctic basin.<br /><br />See the fourth graphic down this page for a less detailed plot:<br />http://dosbat.blogspot.co.uk/2012/09/why-2010-piomas-volume-loss-was.html<br />There's also a spreadsheet with the source data linked to at the end of that post - the V2 plot is the one to use now.<br /><br />That graphic I mention shows the shift you're talking about: The 2-3m and 1-2m categories increase as ice volume is 'demoted' to lower categories.<br /><br />You'll find thickness difference maps here:<br />http://www.arctic-charts.net/volume-charts/InterAnnDiff/<br />Those are interannual differences, March-March and Sept-Sept, so for 2007 the maps shows 2007 thickness at each point minus 2006 thickness. Again that's from PIOMAS.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-54922725921139621512012-09-22T18:24:32.437-07:002012-09-22T18:24:32.437-07:00Thanks for helping make this clear to us all.
See...Thanks for helping make this clear to us all.<br /><br />Seems to me that the whole ice cap is thinning, and the >4m ice is disappearing fastest simply because it is the upper band, and not being replaced, whereas the >4m ice melts and 'becomes' 3m ice. Now that the thickest parts have nearly all been reduced to <4m, it will be the 3m ice that starts to diminish more rapidly next, and so on, until only new ice remains, forming over winter, and totally disappearing each summer, very rapidly I imagine, as the lack of thickness will make it really vulnerable to quick break up and melt.<br /><br />Is there a map showing the change in thickness year on year, I'd like to see the pattern of the rate of change of thickness.<br /><br />Overall it's very worrying, and although there's been a decent amount of media coverage, I haven't seen much political discussion about it. Hopefully the presidential debates in the US might bring it under the spotlight.<br /><br />I'm waiting to see what this winter will bring, weather-wise, with the warnings that it'll be very 'interesting'.<br /><br />Thanks again.Jon Dhttps://www.blogger.com/profile/15348915029836913496noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-39898726510285492592012-09-21T23:11:53.172-07:002012-09-21T23:11:53.172-07:00Thanks Neven,
I think we're on the verge of s...Thanks Neven,<br /><br />I think we're on the verge of some very exciting years.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-34410095327448116372012-09-21T11:54:22.208-07:002012-09-21T11:54:22.208-07:00Yeah, Neven's wife will be a sea-ice widow. ;)...<i>Yeah, Neven's wife will be a sea-ice widow. ;)</i><br /><br />That's not funny! :-p<br /><br />Great stuff, Chris, as always. Instead of ending, I feel like we are only getting started. Let the freeze begin!Nevenhttps://www.blogger.com/profile/15413215743703093876noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-34860744254938566242012-09-21T11:37:30.373-07:002012-09-21T11:37:30.373-07:00John,
Thanks for the comment, there's a core ...John,<br /><br />Thanks for the comment, there's a core of truth in what you say, but glasses of water don't get stratified by salinity and temperatures, and don't have the interaction between ocean and bathymetry, or atmosphere and orography.<br /><br />I do agree with you (checked out your blog) that, especially with the combined risks from AGW and fossil fuel depletion, the UK is too crowded, and that we need to be closing the door to further immigration. <br /><br />I'm reminded of the lifeboat analogy: You're in a packed lifeboat having rowed away from the sinking ship. The ship goes down suddenly dumping hundreds of people in the freezing sea. It may seem that the humane thing to do is to row back to try to help those in the water, but if you do that odds are you'll be sunk by the masses in the water trying to get into your boat. The only rational course of action is to row away from them. Harsh, but survival can be like that. <br /><br />We need to continue international aid and development as we're doing now, last time I read up on it, it seems rather a reasonable approach is being taken by the UK government. But I think it's time to prepare for what the rest of this century will bring, and haul the ladders up now. And NO! That doesn't make me a racist. I take people as I find them regardless of creed or colour. FWIW, the best areas I've lived in previously have been Asian (Hindu/Sikh) - good peaceable neighbours and a low crime rate.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-32182274116891939022012-09-21T07:54:16.523-07:002012-09-21T07:54:16.523-07:00Until the last decade the arctic was receiving 99,...Until the last decade the arctic was receiving 99,000 petajoules more heat in the summer than it could lose in the winter. See: <a href="http://pol-check.blogspot.co.uk/2012/09/the-melting-of-arctic-ice.html" rel="nofollow">The Melting of Arctic Ice</a>. The ice has literally been behaving like ice cubes in tumbler of water. In recent years this excess heat has increased dramatically, perhaps doubling. I think we should be very worried.Johnhttps://www.blogger.com/profile/07442010719863995872noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-70692710918400637542012-09-20T23:04:26.521-07:002012-09-20T23:04:26.521-07:00Peter,
I said 'young' not 'first year&...Peter,<br />I said 'young' not 'first year'. Maslanik's graphic from NSIDC shows decline of ice >4 years old, but more steady levels of ice <4 years old. <br /><br />The question for now is not whether a FY ice pack, that ends the season with no ice, is stable - but whether a predominantly young pack is stable. I had thought we'd see a reduction in volume loss as the pack stabilised with ages typically below 4 years old. So the pack would have been semi-stable (given ongoing forcing from AGW), and could hold area/extent/volume from crashing out in late summer.<br /><br />Anon,<br />Thanks for the comment.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-71597493263501058102012-09-20T15:14:11.550-07:002012-09-20T15:14:11.550-07:00My view had been that the ice was transitioning to...<i>My view had been that the ice was transitioning to a new pseudo-equilibrium state, one with an ice pack composed almost entirely of young ice. I now doubt that such a pseudo-equilibrium state exists...</i><br /><br />Surely it not only doesn't exist but is a contradiction in terms? An ice pack consisting predominantly of young (first-year?) ice is <b>by definition</b> an ice pack that largely melts away every summer. That's, um, why it's young.Peterhttps://www.blogger.com/profile/12559721137290332762noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-19034483966972459582012-09-20T13:49:45.101-07:002012-09-20T13:49:45.101-07:00Been lurking about at various places, wanted to sa...Been lurking about at various places, wanted to say that I think you're dead on here that the main unknowable driver is essentially how the cumulative changes since 2007 have effected other atmospheric and oceanic patterns that could wind up dramatically speeding the process. <br /><br />Is this AD pattern essentially driven by the loss of ice since 2007? We don't know, but it's quite possible, looking likely with the data we have so far. If it's the new summer normal, though, this thing is probably going down fast. 2007 looks to me to have been a quick shift to a new, temporary _atmospheric_ situation that will speed the rest of the system down, and all of the factors will loop into each other. <br /><br />Nature has no particular loyalty to smooth curves, of course. I think we've very much failed to account for the sudden effects past some critical point of having less solid, thick ice -- particularly on weather patterns up there in the summer, which in turn effect the ice, along with how many other factors? <br /><br />That's the problem here to me -- any one of the factors involved may hit what would be its own little "equilibrium" if all else were equal, but there are likely far fewer equilibrium states that can possibly hold that way for all of the relevant parts at once. Each piece of the puzzle will reach for equilibrium and each will fail fairly quickly until they all find it at the same time to satisfy the whole -- how soon will they intersect? How many dependent variables within the bigger picture have we forgotten to include, and how many can we simply not predict with any accuracy whatsoever?<br /><br />We don't know any of it for sure, of course, and figuring out all of the factors that go into these patterns is something I'm very glad I get to think about broadly with some science background but without having to publish anything or try to work the data too hard. I can't imagine how one could even begin to model this well, and those who try really get a lot of crap they don't deserve, IMO, when they turn out to have been off. <br /><br />Also just wanted to say kudos for shifting your views as the data available changes. I'm probably more pessimistic than you about some of the speed here generally -- or at least the potential for it -- but trying to remain open to new thoughts on the subject is so important either way. <br /><br />Back to reading. But many thanks to you and all of the other folks really working on making this all an honest conversation, to the best of your ability.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-74771674901466743402012-09-20T13:30:35.996-07:002012-09-20T13:30:35.996-07:00Yeah, Neven's wife will be a sea-ice widow. ;)...Yeah, Neven's wife will be a sea-ice widow. ;)<br /><br />I know others seem to have IDs and post blog posts there. Looks like it'll have to be a team effort!Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-45802300870182798732012-09-20T13:07:32.533-07:002012-09-20T13:07:32.533-07:00Excellent presentation of the overwhelming evidenc...Excellent presentation of the overwhelming evidence Chris! Additionally, I would add the prediction that it's going to be a busy year with lots of newcomers over at Neven's site!<br />Briandaddybfreehttps://www.blogger.com/profile/04392048213332386108noreply@blogger.com