tag:blogger.com,1999:blog-1367053740188758246.post4638164181692224534..comments2023-06-21T00:39:34.443-07:00Comments on Dosbat: PIOMAS: Calculated thickness.Chris Reynoldshttp://www.blogger.com/profile/16843133350978717556noreply@blogger.comBlogger14125tag:blogger.com,1999:blog-1367053740188758246.post-53891121713498764912012-03-25T02:06:45.535-07:002012-03-25T02:06:45.535-07:00Thanks Lazarus.Thanks Lazarus.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-61787242737264860162012-03-24T07:46:52.875-07:002012-03-24T07:46:52.875-07:00Dr Meier doesn't claim to have said such a thi...Dr Meier doesn't claim to have said such a thing but says;<br /><br />"There is some uncertainty as to when the Arctic Ocean was last ice-free during summer. During the period of ~10,000-5000 years ago, called the Holocene Maximum, temperatures reached their maximum coming out of the ice age and since then there was a slow cooling trend - until the last 40-50 years. Right now temperatures are at or near that climate maximum. There was a paper that reviewed a variety of evidence - mainly from sediment cores at the bottom of the Arctic Ocean, as well and debris along coastlines, and concluded that there was evidence that the Arctic was ice-free or nearly so at that time. However, those data are very sparse, so we can't be conclusive at this point. I've talked to others who don't agree with that date and say it was during the previous interglacial period, ~125,000 years ago when temperatures were even warmer than the Holocene Maximum. We have an article online that discusses this is probably what Steve Goddard is citing:<br /><br />http://nsidc.org/icelights/2011/01/31/arctic-sea-ice-before-satellites/<br /><br />It's important to interpret these results in the proper context though. First, as mentioned above, the amount of data is small and sparse, so there is a lot of uncertainty. Second, when the Arctic Ocean was last sea ice free isn't terribly relevant to the changes we're seeing today and expect to see in the future, except that we do know that there is the potential for the Arctic Ocean to become seasonally ice-free. Third, an ice-free date of 10,000-5000 years ago suggests that the sea ice is more sensitive than if the ocean wasn't ice-free during the Holocene Maximum. If the Arctic Ocean became ice-free during that period, we would expect the Arctic Ocean to become ice-free again under similar temperatures. Given that we're at or near those temperatures and expect those temperatures to continue to rise through the coming century, it gives us even more confidence that we'll be seeing a seasonally ice-free Arctic Ocean in the not-too-distant future (~20-40 years)."<br /><br />I think Kevin has linked to that actual research paper that all this relates too in a comment on that thread.Lazarushttps://www.blogger.com/profile/14139033650731770470noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-9755095354700480282012-03-23T09:34:09.028-07:002012-03-23T09:34:09.028-07:00Re the above...
I had to find that using site sea...Re the above...<br /><br />I had to find that using site search - have made a reply there now, I tend to forget when I post at Goddard's.<br /><br />Have you found out anything interesting from Dr Meier?Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-49796353901286676662012-03-23T09:27:31.681-07:002012-03-23T09:27:31.681-07:00It's here I think:
http://www.real-science.co...It's here I think:<br /><br />http://www.real-science.com/death-spiral-continues-unabatedChris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-3298044933804126702012-03-23T04:20:28.068-07:002012-03-23T04:20:28.068-07:00Chris, sorry to go off topic but you posted on God...Chris, sorry to go off topic but you posted on Goddard's blog and he mentioned Dr. Walt Meier. I have had an email exchange with Dr Meier but I have lost track of Goddard's post (soo many).<br /><br />Do you have a record of it or link?Lazarushttps://www.blogger.com/profile/14139033650731770470noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-24136438736489875132012-03-22T11:49:11.987-07:002012-03-22T11:49:11.987-07:00I hope you're wrong Lazarus.I hope you're wrong Lazarus.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-31267130182125617442012-03-20T06:02:06.878-07:002012-03-20T06:02:06.878-07:00Interesting stuff. Thinking about the PIOMAS volum...Interesting stuff. Thinking about the PIOMAS volumes compared to the extent, the extent has been holding up pretty well - some on the denial side have been making much of this fact recently.<br /><br />It strikes me that in contrast, with the thickness dropping so dramatically, an almost wholly ice free summer will happen quite suddenly and within a few years. Once the thin ice starts to break up, even thought extent looks near normal, it will disappear quickly. In my mind it could occur at any time depending on prevailing conditions, and I suspect it may even bounce back a bit in the years after giving the denial crowd another false metric about recovery.<br /><br />I'd put my money on a mostly ice free Arctic in summer between 2015 and 2020.Lazarushttps://www.blogger.com/profile/14139033650731770470noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-33362048615173687992012-03-19T12:00:39.428-07:002012-03-19T12:00:39.428-07:00Thanks Hank,
I've been somewhat ahead of Bob ...Thanks Hank,<br /><br />I've been somewhat ahead of Bob Grumbine's objections to the use of extent in that in subsequent posts I've used area, and will use it in the future.<br /><br />I've shelved this issue for the time being as a lot of the interpretation of what's going on with volume depends on what happens this Spring. Now it's a matter of waiting. If we do see a re-run of 2010/11 by June/July I'll re-do the substance of these posts in a more comprehensive manner. They're not as tidy an succinct as they might have been in retrospect, but what you see here is a train of thought as I looked into the matter.<br /><br />I still remain convinced this is important and expect a re-run of massive spring losses this year.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-84849353637865466482012-03-18T20:00:50.507-07:002012-03-18T20:00:50.507-07:00I asked over at Robert Grumbine's:
http://www....I asked over at Robert Grumbine's:<br />http://www.blogger.com/comment.g?blogID=5337555368793819627&postID=8739505743478043645Hank Robertshttps://www.blogger.com/profile/07521410755553979665noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-82558428615301969502012-03-13T13:05:24.446-07:002012-03-13T13:05:24.446-07:00I see what you mean regards salinity in the Atlant...I see what you mean regards salinity in the Atlantic sector. Available as HYCOM SSS here:<br />http://www7320.nrlssc.navy.mil/hycomARC/arctic.html<br /><br />I've been browing the archives and there's a similar intrusion of salty Atlantic water in 2011, this year and 2011 look fairly similar - but I agree it's annoying that they don't keep the same colour scheme.<br /><br />Interpolated OLR,<br />http://www.esrl.noaa.gov/psd/data/gridded/data.interp_OLR.html<br />Try this, Dec to Feb, 2007 - 2011 minus 2002 - 2006, do as both Interpolated OLR and OLR. The former has substantial positive anomaly of the order of 10W/m^2, the latter has positive and negative anomalies. Or try just one year, eg 2011 Dec-Feb, interpolated shows an increase in emission, normal OLR shows a mixture of positive and negative anomalies.<br /><br />Interpolated OLR uses an algorithm to fill in the gaps from satellite data. Given that interpolated OLR shows consistent positive anomalies whereas non interpolated shows a mix of positive and negative suggests that conclusions from OLR may not be straightforward, or that conclusions from straight OLR might not be. However a good reason to expect increased OLR is the warming and humidity increase of the Arctic atmosphere. There is a reference on the page link I gave about inter-OLR.<br /><br />I must admit I'm clueless as to what this year will bring. I expect to see the spring volume loss again, but will be relieved if it doesn't happen, after that I haven't the foggiest. I'm still to be persuaded that any strong conclusions can be gained from speculation based on conditions now. Although I know the regulars over at Neven's derive a lot of enjoyment from doing so - and I'm not about to stop people enjoying the same hobby as I enjoy. :)Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-42055293524056451542012-03-12T20:54:15.996-07:002012-03-12T20:54:15.996-07:00Chris, Agreed on the ridge and the salinity. I do ...Chris, Agreed on the ridge and the salinity. I do try to gauge salinity from the PIPS maps, but they're difficult to get a good comparison from - they (PIPS) keep changing the scale colors. My impression is that it's slowly getting saltier in the eastern basin.<br /><br />I'm not sure how to take this, but so far 2012 is mimicking 2010. If you view CT Today's <a href="http://arctic.atmos.uiuc.edu/cryosphere/arctic.sea.ice.interactive.html" rel="nofollow">Interactive spaghetti graph</a> and eliminate all the years except for 2012 and 2010 they're dead ringers for each other. Click on the year in the legend to add or eliminate it from the graph.<br /><br />I spent a couple of hours playing with the monthly composites at NCEP/NCAR today. Breaking News! The arctic is warmer today than it was in the past :)<br /><br />Fortunately I don't know anything about "Interpolated OLR" - if I did, I might be *really* alarmed. <br />Viewing DJF monthly composites for the arctic, Interpolated OLR for this recent years shows a continuing encroachment pattern that is spreading into the basin from the Atlantic and Russian sectors and creating a smaller and smaller fortress against Greenland and the Canadian Archipelago. This has been evident in many other measures as well, of course.<br /><br />What I think the Interpolated OLR is telling me is that the ice is definitely in bad shape everywhere but for that small sliver of nearly fast MY ice - and the protection for that area is getting weaker and weaker.<br /><br />I would expect the Chukchi and Beaufort Seas to be a bit slower this year, but I think the Laptev and Kara Seas will be launching points for inroads into the basin like we've never seen before. I'm pretty much at even odds there's open water to the pole this year.Kevin O'Neillhttps://www.blogger.com/profile/06692943768484857724noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-6551606630857951612012-03-12T12:54:19.618-07:002012-03-12T12:54:19.618-07:00I've just remembered - the Atlantic water is s...I've just remembered - the Atlantic water is salty and dense, as it hits the edge of the abyss under the ice it sinks below a cap of fresher less dense Arctic water which is, I think, why the Atlantic sector ice hasn't moved as much as the Pacific Sector (Beaufort Chucki through to Siberian coast). <br /><br />If I remember correctly then this would mean that we probably won't see massive loss in the Atlantic sector, despite apparent preconditioning - whereas if that preconditioning were in the Pacific / Siberian sector we'd likely see a substantial impact.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-5928996434385642432012-03-12T12:23:38.577-07:002012-03-12T12:23:38.577-07:00From what I've read the correlation between Wi...From what I've read the correlation between Winter conditions and the September minimum isn't strong.<br /><br />Bitz "On the maintenance of the sea ice edge" shows that in the Atlantic sector there is a net heat flux (ocean & solar) of 100W/m^2 along the ice edge in the Atlantic sector. The Greenland Sea spur of ice along the coast of Greenland only exists because of a continual supply of ice from the Transpolar Drift. However further east towards Barents is more interesting. Models simulate the location of the ice edge there, but I'm not sure how accurate their bathymetry is.<br /><br />I mention that because it seems hard to see how it could be a coincidence that the ice edge tracks the edge of the abyssal deep poleward of Svalbard, Franz Josef Land and Svernya Zemlya. I'm sure I've read something before about how that abyssal deep's cold pool interacts with Atlantic water and keep the ice edge there - but I'm bushed after a long day at work.<br /><br />But for that complication I'd fully expect to see 'rotten ice' well into the pack from that region.<br /><br />I've been pondering this thickness issue some more. If I'm right and the area minima volume is biassed up by ice off the CAA it may be possible to adjust for that volume ad get a picture of how thickness in the basin is changing outside the area covered at minimum.<br /><br />PS, don't know if you've had the chance but have you looked at the NCEP/NCAR plots yet - could part of the warmth of 2010/11 be accounted for by the Warm Arctic Cold Continent's pattern visible in 2010 01 and 2011 01?Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-62144393989891589282012-03-11T15:16:31.066-07:002012-03-11T15:16:31.066-07:00Chris, It's an interesting race. We see larg...Chris, It's an interesting race. We see large gains in extent/area during one of the warmest of arctic winters. One would suppose, then, that the ice is thin and preconditioned for early melt. Yet we have to always keep in the back of our minds that weather still plays a significant role in any given year.<br /><br />I'll be interested to see if this melt season follows the patterns of past years. I benchmark certain points - usually the various 'million sq km' points because they're easy to keep track of and percentages of maximums (extent and/or area).<br /><br />The Atlantic sector appears so weak that I'm especially interested to see what defenses the arctic has left at its disposal. In the Pacific sector we see MYI pushed into the Transpolar Drift and thrown up like an arm across the Beaufort Gyre to ward off the increasing warmth. Is there a trick to keeping the Atlantic sector safe that we haven't seen yet? Perhaps banks of fog to keep insolation from reaching the surface .... it's all speculation at this point, but in another 45 - 60 days we'll have the early data telling us what we might expect come fall.Kevin O'Neillhttps://www.blogger.com/profile/06692943768484857724noreply@blogger.com