tag:blogger.com,1999:blog-9959776.post7668250390969802867..comments2024-02-15T04:42:41.606+00:00Comments on James' Empty Blog: BEST laugh of the dayJames Annanhttp://www.blogger.com/profile/04318741813895533700noreply@blogger.comBlogger36125tag:blogger.com,1999:blog-9959776.post-16873872166013256742013-02-04T19:48:48.063+00:002013-02-04T19:48:48.063+00:00Just wanted to say I greatly enjoyed reading this ...Just wanted to say I greatly enjoyed reading this post and comments. Oops, that sounds spammy, I should prove I'm not a spambot... er... looking forward to seeing more tools for estimating the predictive reliability of IPCC future warming estimates? (But then, aren't we all, I suppose.) <br /><br />Well, I <i>feel</i> human, anyway.Davehttps://www.blogger.com/profile/11877699517690934530noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-80776240607660164872013-01-31T13:47:45.769+00:002013-01-31T13:47:45.769+00:00Found a copy of the actual paper.
A couple of thi...Found a copy of <a href="http://folk.uio.no/gunnarmy/paper/aldrin_env_2012.pdf" rel="nofollow">the actual paper.</a><br /><br />A couple of things I've noticed: Their fitted posterior, from which they presumably derive the sensitivity estimate, appears to significantly underestimate NH warming.<br /><br />A related matter is that the posterior fit shows more warming in the SH than NH, despite that being far from the case in observations. This presumably happens because the simple climate model used to inform their method is fed with differential aerosol forcing in each hemisphere, and greater net forcing in the SH is fairly linearly translated into more warming.<br /><br />However, the more complex CMIP5 models generally produce more NH warming over the historical period, even those featuring large negative aerosol forcing.Paul Shttps://www.blogger.com/profile/15275182941476518621noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-77363372627709684512013-01-30T23:58:40.441+00:002013-01-30T23:58:40.441+00:00The old Aldrin paper is all there is at this momen...The old Aldrin paper is all there is at this moment. the other comes from unpublished material... What that will say when it is published is hard to know. Magnushttps://www.blogger.com/profile/01617272924116099306noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-88298542665752919792013-01-30T11:03:22.352+00:002013-01-30T11:03:22.352+00:00James,
Perhaps stupidly, I hadn't considered ...James,<br /><br />Perhaps stupidly, I hadn't considered the press release might simply be wrong. I don't have access to the Aldrin paper but page 25 of <a href="http://www.newton.ac.uk/programmes/CLP/seminars/120812001.pdf" rel="nofollow">this slideshow</a> appears to indicate their posterior mean estimate is remarkably insensitive to a change of scope, whether using data up to 2009, 2000 or 1990.<br /><br />The way these things go I wouldn't be surprised if this 3.7 figure was a misunderstanding of the paper or someone involved quoting the accepted radiative forcing of doubled CO2. The only other obvious possibility I can see is that 3.7 might have been the posterior climate sensitivity found for data up to 2000 when including a -0.5W/m^2 cloud lifetime term.Paul Shttps://www.blogger.com/profile/15275182941476518621noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-59546483169546507962013-01-30T05:49:51.478+00:002013-01-30T05:49:51.478+00:00Paul, yes I'm a bit surprised at the 3.7 figur...Paul, yes I'm a bit surprised at the 3.7 figure, as it does not seem consistent either with the published Aldrin et al paper or anything else of a similar ilk (which generally find a best estimate of under 3C, even for the older estimates with less data and high tails, eg fig 9.20 in the IPCC AR4).James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-56092538557005776122013-01-29T20:25:35.283+00:002013-01-29T20:25:35.283+00:00Eli,
I'm talking about long term trends over ...Eli,<br /><br />I'm talking about long term trends over the whole record rather than inter-annual fluctuations. If the theoretical coefficient fluctuates it will still average to a single value over the whole period.<br /><br />That said, this possibility of fluctuating coefficients is why the situation is better analysed through AMIP GCMs rather than simple statistical models.Paul Shttps://www.blogger.com/profile/15275182941476518621noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-78978427287214240362013-01-29T17:47:18.509+00:002013-01-29T17:47:18.509+00:00"No, I can't see how that would follow. E..."No, I can't see how that would follow. Essentially what I'm saying is that the mid-upper troposphere temperature change at any particular location can, to some extent, be calculated as a function of surface temperature change (SAT)"<br /><br />Except where the constant changes. See 1998.EliRabetthttps://www.blogger.com/profile/07957002964638398767noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-85141008108964634622013-01-29T15:49:06.844+00:002013-01-29T15:49:06.844+00:00James,
Regarding the Aldrin paper and the report ...James,<br /><br />Regarding the Aldrin paper and the report that climate sensitivity reduces from 3.7 to 1.9 when 2000-2010 data is included...<br /><br />wouldn't that mainly indicate a problem with the method? Making small variations to the scope of input datasets is a common test of robustness, which this method seems to have failed.Paul Shttps://www.blogger.com/profile/15275182941476518621noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-50951512184193410272013-01-29T15:38:48.212+00:002013-01-29T15:38:48.212+00:00Although I don't fully understand your point, ...<i>Although I don't fully understand your point, it does seem that you are not actually contradicting Lindzen here.</i><br /><br />As far as I can see Lindzen is simply referring to a much-raised issue, and then speculating on a possible cause. There isn't much to directly contradict. My point is a more general one: there are really two separate issues here that are often confused on climate blogs.<br /><br /><i>Wouldn't it follow from your point as well that the surface record is less likely to be reliable?</i><br /><br />No, I can't see how that would follow. Essentially what I'm saying is that the mid-upper troposphere temperature change at any particular location can, to some extent, be calculated as a function of surface temperature change (SAT), e.g.<br /><br />DeltaTropos = c * DeltaSAT<br /><br />where c is some coefficient relating to the expected Tropos/SAT amplification over a particlar region. The presence of the infamous red spot over the tropics is thus dependent on the distribution of temperature change at the surface - a large bias towards high latitude NH warming and relatively little in the tropics, as we see in SAT+SST observations, is a pattern in which a prominent tropical hotspot would not be expected.<br /><br />-----------------<br /><br />The second issue is whether the mid-upper troposphere over the tropics specifically is warming in-line with expectations due to surface warming in the tropics. It seems to me that AMIP model experiments using prescribed SSTs from observations provide a good route for interrogating this question, as described in an <a href="http://www.gfdl.noaa.gov/blog/isaac-held/2012/01/01/21-temperature-trends-msu-vs-an-atmospheric-model/" rel="nofollow">Isaac Held blog post</a>. Prescribing SSTs means that surface warming in the models has a similar spatial distribution to that seen in observations. You can see in Held's post that the model output is very similar to RSS-observed TLT data.<br /><br />This is where I would suggest that Lindzen's speculation concerning the accuracy of SST measurements appears unfounded. I can't see how the model could so faithfully reproduce the variance in the observed TLT time series if surface SST measurements were not sufficiently representative.<br /><br />This is not to say the issue is at all settled, not even close. <a href="http://www.atmos.uw.edu/~qfu/Publications/erl.pochedley.2012.pdf" rel="nofollow">Po-Chedley & Fu 2012</a> provide a wider examination of the AMIP models against observations. Also, comparisons between models and satellite TLT data can't definitively validate since the satellite data doesn't have a great enough fidelity to isolate the particular vertical region of interest: instead it picks up varying trends all through the atmosphere and is a weighted average. Theoretically I think you could get similar TLT time series form very different vertical temperature trend profiles.Paul Shttps://www.blogger.com/profile/15275182941476518621noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-11944546499263050952013-01-28T22:45:34.876+00:002013-01-28T22:45:34.876+00:00True... btw, no new study jet if you missed that.True... btw, no new study jet if you missed that.Magnushttps://www.blogger.com/profile/01617272924116099306noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-9464729697000728192013-01-28T10:10:37.502+00:002013-01-28T10:10:37.502+00:00Well some of us might have some "inside info&...Well some of us might have some "inside info" in that we've seen the drafts...though they could change...so betting is probably not a great idea at this point :-)James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-52372483759430848692013-01-27T14:15:07.694+00:002013-01-27T14:15:07.694+00:00Thnx, I have seen that you had a look at the IPCC ...Thnx, I have seen that you had a look at the IPCC part dealing with this... wich seams to me wont change the ECS much... might cut uncertenty in the high end... now that might change... ofc but a bet on 3 c (2-4.5) in ECS in the new IPCC report seams to be a good one?Magnushttps://www.blogger.com/profile/01617272924116099306noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-7745586839580137572013-01-27T08:00:47.161+00:002013-01-27T08:00:47.161+00:00Looks like it might be that paper, though strange ...Looks like it might be that paper, though strange timing if so...<br /><br />Andy Revkin has <a href="http://dotearth.blogs.nytimes.com/2013/01/26/weaker-global-warming-seen-in-study-promoted-by-norways-research-council/" rel="nofollow">a post and quotes me in a comment</a>.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-42058148104568202202013-01-26T15:13:20.843+00:002013-01-26T15:13:20.843+00:00Sorry might be wrong paper...
http://www.forskning...Sorry might be wrong paper...<br />http://www.forskningsradet.no/en/Newsarticle/Global_warming_less_extreme_than_feared/1253983344535/p1177315753918Magnushttps://www.blogger.com/profile/01617272924116099306noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-34631030630335621772013-01-26T15:09:15.837+00:002013-01-26T15:09:15.837+00:00How novel is this approach to get the sensitivity?...How novel is this approach to get the sensitivity?<br />http://onlinelibrary.wiley.com/doi/10.1002/env.2140/abstract;jsessionid=FDF33A1FB2762A4213CD031F01EF2A10.d01t04<br /><br />2000 figures make the difference<br />When the researchers at CICERO and the Norwegian Computing Center applied their model and statistics to analyse temperature readings from the air and ocean for the period ending in 2000, they found that climate sensitivity to a doubling of atmospheric CO2 concentration will most likely be 3.7°C, which is somewhat higher than the IPCC prognosis.<br /><br />But the researchers were surprised when they entered temperatures and other data from the decade 2000-2010 into the model; climate sensitivity was greatly reduced to a “mere” 1.9°C.Magnushttps://www.blogger.com/profile/01617272924116099306noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-19749355289926114122013-01-25T23:49:17.000+00:002013-01-25T23:49:17.000+00:00So does the google :-)So does <a href="http://trophybiking.files.wordpress.com/2011/12/troll.jpg" rel="nofollow">the google</a> :-)James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-4381793275976098772013-01-25T23:14:55.962+00:002013-01-25T23:14:55.962+00:00Soon-to-vanish spam above: "Troll Images of ...Soon-to-vanish spam above: "Troll Images of Girls"<br /><br />The imagination runs wild. :)Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-781140327703405582013-01-25T00:35:37.921+00:002013-01-25T00:35:37.921+00:00Paul S.,
Thanks for your comments.
The point bei...Paul S.,<br /><br />Thanks for your comments.<br /><br /><i>The point being that there is a dependence here on the spatial distribution of temperature trends at the surface. The simple example I've given is actually not far from what is actually observed.<br /><br />From what I can see, most of the discrepancy between what models predict for differential zonal atmospheric temperature trends and what is found in observations is a result of a similar spatial discrepancy at the surface.</i><br /><br />Although I don't fully understand your point, it does seem that you are not actually contradicting Lindzen here. Wouldn't it follow from your point as well that the surface record is less likely to be reliable? In any case when you say this is close to what is observed do you have a paper in mind that says this? Only reason being I'd just like to understand this better.Alex Harveyhttps://www.blogger.com/profile/10591760549272940968noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-50196412592538597562013-01-24T13:57:02.141+00:002013-01-24T13:57:02.141+00:00Dear James,
I forgot to provide a citation. The ...Dear James,<br /><br />I forgot to provide a citation. The paper is <br /><br />R.S. Lindzen (2012): 'Climate physics, feedbacks, and reductionism (and when does reductionism go too far?)', European Physical Journal Plus, DOI 10.1140/epjp/i2012-12052-8.<br /><br />I quoted the relevant section in full. The Lindzen and Nigam paper cited therein is (the much cited) paper -<br /><br />R.S. Lindzen and S. Nigam (1987). 'On the role of sea surface temperature gradients in forcing low level winds and convergence in the tropics'. J. Atmos. Sci., 44, 2418-2436.Alex Harveyhttps://www.blogger.com/profile/10591760549272940968noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-78978495057902910282013-01-24T06:54:51.658+00:002013-01-24T06:54:51.658+00:00There's also this at least somewhat related pa...There's also <a href="http://geotest.tamu.edu/userfiles/216/dessler2013.pdf" rel="nofollow">this</a> at least somewhat related paper, which was on his site.<br /><br />FWIW I did an exact phrase search on the Lindzen passage AH quoted and turned up nothing. Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-83982641272311419462013-01-24T06:39:22.174+00:002013-01-24T06:39:22.174+00:00Had to wrack my brain for where I saw it reference...Had to wrack my brain for where I saw it referenced since it doesn't seem to have appeared in Google Scholar yet, plus Andy seems not to have updated his site recently enough to show it, but <a href="http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50199/abstract" rel="nofollow">here</a> it is. <a href="http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00547.1" rel="nofollow">This</a> may also be relevant.<br />Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-13656235119855073382013-01-24T01:02:41.867+00:002013-01-24T01:02:41.867+00:00What is the Dessler thing? Link?What is the Dessler thing? Link?James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-5605033770809499542013-01-24T00:00:02.308+00:002013-01-24T00:00:02.308+00:00And bizarrely, AH is not so interested in the fres...And bizarrely, AH is not so interested in the fresh validation of Dessler (2010). Imagine that.Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-25846740253971294242013-01-23T23:58:26.602+00:002013-01-23T23:58:26.602+00:00"(...) executing the significance of latest r..."(...) executing the significance of latest research." Nice catch, Hank!Steve Bloomhttps://www.blogger.com/profile/12943109973917998380noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-5926090953974205702013-01-23T22:51:52.336+00:002013-01-23T22:51:52.336+00:00I'm afraid that Lindzen's signal to noise ...I'm afraid that Lindzen's signal to noise ratio is sufficiently low that I would need some persuasion to bother looking at it. Where is this "most recent paper" published?James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.com