tag:blogger.com,1999:blog-1367053740188758246.post7994673809548984779..comments2023-06-21T00:39:34.443-07:00Comments on Dosbat: PIOMAS: The Porch and the Roof.Chris Reynoldshttp://www.blogger.com/profile/16843133350978717556noreply@blogger.comBlogger9125tag:blogger.com,1999:blog-1367053740188758246.post-57358715528974697212012-03-11T13:26:31.809-07:002012-03-11T13:26:31.809-07:00No I've not yet read that paper, been busy dig...No I've not yet read that paper, been busy digging myself out of a hole tonight.<br /><br />My latest post was FUBAR - I posted an earlier version after a large re-write that changed a major conclusion. When I saved it last night my system glitched, IE restarted and it obviously didn't save the new version.<br /><br />So I've re posted it and written a large chunk again.<br /><br />I'll print the Francis paper out and read it on the bus.<br /><br />Dr Francis also gave me her explanation of why she thinks the Jetstream has a role in the development of the Arctic Dipole, I need to email her again about that because I'm not convinced, which may mean I don't get it.<br /><br />I'll email you shortly.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-75823405263612539302012-03-11T11:25:09.259-07:002012-03-11T11:25:09.259-07:00Chris, yes the email address is correct.
Have y...Chris, yes the email address is correct. <br /><br />Have your read Dr Francis' latest paper yet? Short, concise, and clear. <br /><br />All of this research you've been detailing is presenting a coherent story: arctic sea ice reduction is driving the weather - not the other way around (as skeptics would prefer to have it).<br /><br />It's the wind!<br />It's the AO!<br />It's the NAO!<br /><br />Ummm, no, it's not. It's a bit more complicated and far more interesting than that. I guess that puzzles me more than anything - the actual science is far more *interesting* than simplistic explanations. <br /><br />I've a co-worker who spends a lot of time exploring Intelligent Design web-sites. He notes the same thing in the denial of evolution realm - the science is far more interesting than their simplistic explanations. Deniers in any area simply miss out on a lot of fun, interesting research.Kevin O'Neillhttps://www.blogger.com/profile/06692943768484857724noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-5080674386994433882012-03-11T10:18:12.936-07:002012-03-11T10:18:12.936-07:00Kevin,
Is the email address on your profile curre...Kevin,<br /><br />Is the email address on your profile current?<br /><br />I've got all seasons NCEP/NCAR anomaly plots from 2005 to 2011. Total 28 files and 1.08Mb, I've got them as a zip file which would be more convenient.<br /><br />Do you have Winzip? Or equivalent.<br /><br />I can't see an obvious difference between 2010/11 and the rest that would explain the warm anomaly. However both Winter 2011 & 2010 (Jan-Mar) show a clear Warm Arctic Cold Continents configuration, which might add to it. <br /><br />As I say, I can't find a reason right now but will check them out again and see if anything occurs to me.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-58373183314961289742012-03-10T15:24:23.469-08:002012-03-10T15:24:23.469-08:00Chris, yes there are lots of caveats on the applic...Chris, yes there are lots of caveats on the applicability of 64N - 90N temperature anomalies to this problem. That's why I termed it a first clue.<br /><br />Surface temperatures should suffice, but I really don't want to download the whole gridded database for LOTI, then parse it out for particular latitudinal bands and then map it to exclude land.<br /><br />The DMI 80N graphs don't help much because 1) we're not sure *where* the PIOMAS volume losses are geographically; and 2) we know the melt season surface temperatures above 80N are constrained to a few tenths around 0C (On this point, if we ignored the physics, we might come to the same conclusion as Steve Goddard; look at DMI, nothing has changed in Arctic summer since 1959!), and 3)DMI's north of 80N graphs ignore most of the area where we observe sea ice area and extent (and possibly volume) losses.<br /><br />Still, the DMI graphs have been 'texted' (<a href="http://climatesanity.wordpress.com/2009/09/08/numerical-version-of-dmi-arctic-temperature-data/" rel="nofollow">by a skeptic</a> - thru Sept 2009) so I have them in Excel and will see if I can tease anything meaningful from them. My initial look says, "No."Kevin O'Neillhttps://www.blogger.com/profile/06692943768484857724noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-43911186866227132302012-03-10T13:06:21.863-08:002012-03-10T13:06:21.863-08:00Bloody Hell! that's a serious increase in temp...Bloody Hell! that's a serious increase in temperature. Although bear in mind that's an annual average for land & ocean. The ocean increase very likely won't be as much. And as it's an annual average much of it might be in the Autumn and Winter. Is it cause or effect - thinner ice will warm the atmosphere.<br /><br />That said it does imply warmer ice.<br /><br />There are some bouy flux and ocean temperature measurements here:<br />http://www.oc.nps.edu/~stanton/fluxbuoy/deploy/deploy.html<br />#17 is a long timeseries - no notable change.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-89961968463802146912012-03-10T12:53:06.960-08:002012-03-10T12:53:06.960-08:00Kevin,
"Volume losses in the 2nd half of the...Kevin,<br /><br />"Volume losses in the 2nd half of the melt season have slowed down."<br /><br />Yes there is a notable decrease in volume anomaly as you go through the Summer, but I'm still unable to rule out area changes as playing a role. Perhaps I'm being overly fussy.<br /><br />In comments on the previous post you mentioned warm ice. I replied that thinner ice will be warmer because of increased heat flux from ocean to atmosphere. It's a bit too late for calculations on a Saturday night but.<br /><br /><a href="http://en.wikipedia.org/wiki/Sea_ice_thickness#Determining_surface_heat_flux" rel="nofollow">Wikipedia</a> has an entry on thermal conductivity of sea-ice. From which Q = k(Ts-Tw)/h<br /><br />Q is net heat flux, k is conductivity of ice, Ts is surface temp, Tw water temp, and h is thickness.<br /><br />From <a href="http://researcharchive.vuw.ac.nz/handle/10063/313" rel="nofollow">this page</a> FY sea ice has a conductivity of around 2.3 W/m degC.<br /><br />assume surface temp is -20 ocean is zero, vary h from 2m down to zero in steps of 0.1.<br /><br />-23.000<br />-24.211<br />-25.556<br />-27.059<br />-28.750<br />-30.667<br />-32.857<br />-35.385<br />-38.333<br />-41.818<br />-46.000<br />-51.111<br />-57.500<br />-65.714<br />-76.667<br />-92.000<br />-115.000<br />-153.333<br />-230.000<br />-460.000<br /><br />Because thickness is the denominator decreasing it has a strongly non linear response of the form 1/x. The temperature gradient through the ice will be steeper and while the very surface layer will be -20deg, the bottom layer 0degC, the bulk of the ice will be warmer.<br /><br />I'm beggining to suspect you're correct - warmer sea-ice melts sooner. However this is such a simple effect that it has to be included in ice physics.<br /><br />I wonder what result would be from stacking that equation in layers. The specific heat of ice would convert heat flux to temperature I think.Chris Reynoldshttps://www.blogger.com/profile/16843133350978717556noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-66480302413873385102012-03-10T12:30:09.652-08:002012-03-10T12:30:09.652-08:00Chris, the first clue I've found are the zonal...Chris, the first clue I've found are the zonal mean Land Ocean Temperature anomalies <a href="http://data.giss.nasa.gov/gistemp/tabledata_v3/ZonAnn.Ts+dSST.txt" rel="nofollow">from GISS incorporating GHCNv3</a><br /><br />LOTI Zonal Anomalies for 64N - 90N<br /> <br />Year deg C<br />2000 1.05<br />2001 0.98<br />2002 1.27<br />2003 1.46<br />2004 0.7<br />2005 1.95<br />2006 1.67<br />2007 1.97<br />2008 1.4<br />2009 1.29<br />2010 2.11<br />2011 2.24<br /><br />We see that 2010/2011 have the two largest anomalies with 2007 just behind. The mean for 1979 to 2011 is .82Kevin O'Neillhttps://www.blogger.com/profile/06692943768484857724noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-8470302863274310412012-03-10T09:57:45.263-08:002012-03-10T09:57:45.263-08:00This explains both the decreased amplitude of the ...<i>This explains both the decreased amplitude of the thickness graph and the disappearance of the porch.</i><br /><br />Should be 'roof' not porch.Kevin O'Neillhttps://www.blogger.com/profile/06692943768484857724noreply@blogger.comtag:blogger.com,1999:blog-1367053740188758246.post-90160706261279243852012-03-10T09:56:25.627-08:002012-03-10T09:56:25.627-08:00Chris, I posted some numbers over at Neven's f...Chris, I posted some numbers <a href="http://neven1.typepad.com/blog/2012/03/piomas-march-2012.html?cid=6a0133f03a1e37970b0168e8a395e1970c#comment-6a0133f03a1e37970b0168e8a395e1970c" rel="nofollow">over at Neven's</a> following on your PIOMAS comment.<br /><br />Volume losses in the 2nd half of the melt season have slowed down. This helps explain the disappearance of the roof. I think this might be due to the 'easily' melted ice already gone by late summer. So, in a sense it's due to shifting from the late summer bin to the early summer bin - *BUT* the early summer bin has increased by far more than just this amount.<br /><br />We're seeing a shift in when ice melts AND an increase in overall melt. This explains both the decreased amplitude of the thickness graph and the disappearance of the porch.<br /><br />What it does NOT explain is why. I'm still of the initial guess that warmer winters are leaving the ice better prepped for early melt. Now if I can find a decent dataset to plot alongside PIOMAS I can see if there's any actual correlation.Kevin O'Neillhttps://www.blogger.com/profile/06692943768484857724noreply@blogger.com