tag:blogger.com,1999:blog-9959776.post6499183971259739462..comments2024-02-15T04:42:41.606+00:00Comments on James' Empty Blog: Curiouser and curiouserJames Annanhttp://www.blogger.com/profile/04318741813895533700noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-9959776.post-64786012021143241052009-08-21T23:09:16.229+01:002009-08-21T23:09:16.229+01:00NCDC land/ocean ratio is actually 2.6, not 2.8. Th...NCDC land/ocean ratio is actually 2.6, not 2.8. The difference appears to be due to update in the NCDC (land is now .300°C/dec., not.31°C/dec. with ocean at 0.114°C/dec.), as well as possible rounding error.<br /><br />Also worth noting, the ocean warming has dropped off a little in NCDC. 1979-2005 was 0.132°C/dec., resulting in land/ocean ratio of 2.3 in that time frame.Deep Climatehttps://www.blogger.com/profile/07739846320319167391noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-42960715023655027882009-08-20T23:32:04.971+01:002009-08-20T23:32:04.971+01:00Sutton et al didn't say which model had which ...Sutton et al didn't say which model had which ratio, but over that recent interval, maybe the aerosol forcing has actually reduced (this factor is fingered for the recent rapid warming over Europe at least). Maybe there's also a chunk of natural variability.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-43423428357726008552009-08-20T22:15:38.979+01:002009-08-20T22:15:38.979+01:00Actually I've reread Gavin's letter to Klo...Actually I've reread Gavin's letter to Klotzbach a little more carefully and he gives the GISS-ER figures:<br /><br /><i>As might be expected, the land temperatures rise faster than the global mean or ocean values (0.26 deg C/dec vs. 0.17 deg C/dec and 0.14 deg C/dec) </i><br /><br />So land to ocean trend ratios are:<br />GISS-ER: 1.9 (1979-2005)<br /><br />SAT obs (1979-2008)<br />HadCru: 1.6<br />GisTemp:2.3<br />NCDC: 2.8Deep Climatehttps://www.blogger.com/profile/07739846320319167391noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-73979577284080544742009-08-20T18:00:13.027+01:002009-08-20T18:00:13.027+01:00oh, and:
Global: +0.16°C/decadeoh, and:<br />Global: +0.16°C/decadebobunkhttps://www.blogger.com/profile/07700713209346702770noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-15319318422445594472009-08-20T17:49:47.118+01:002009-08-20T17:49:47.118+01:00GISTEMP (1979-2008):
Land: +0.28°C/decade
Ocean: +...GISTEMP (1979-2008):<br />Land: +0.28°C/decade<br />Ocean: +0.12°C/decadebobunkhttps://www.blogger.com/profile/07700713209346702770noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-73699202086589908922009-08-19T23:18:37.522+01:002009-08-19T23:18:37.522+01:00The land-ocean warming ratio covers a range of abo...The land-ocean warming ratio covers a range of about 1.4-1.8 in models. <a href="http://atmosdyn.yonsei.ac.kr/nrl/seminar/Sutton_etal_GRL2007.pdf" rel="nofollow">Here's a paper</a> (Sutton et al GRL 2007)<br /><br />Note, however, that they used 1%pa CO2 runs and realistic aerosol loading will (I expect) reduce this ratio by primarily cooling over land.James Annanhttps://www.blogger.com/profile/04318741813895533700noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-9490489338659344772009-08-19T20:15:19.732+01:002009-08-19T20:15:19.732+01:00There is one large discrepancy between data sets t...There is one large discrepancy between data sets that is not discussed in Klotzbach et al, but may be the most interesting aspect to emerge from the analysis.<br /><br />The land-ocean differential in NCDC is remarkable over 1979-2008: 0.31C/decade (land) vs. 0.11C/decade (ocean), for a trend difference of 0.20C/decade. HadCRU has 0.22C/decade (land) vs. 0.14C/decade (ocean), with a differential of less than half that of NCDC, i.e. 0.08C/decade.<br /><br />So an interesting question for further study would be: where in this wide range of land-ocean differential do climate models generally fall? And what are possible explanations for the wide discrepancies (especially over land)?<br /><br />A first thought that occurs to me is that the latitudinal masks may be different in the various data sets - certainly something to watch out for.Deep Climatehttps://www.blogger.com/profile/07739846320319167391noreply@blogger.comtag:blogger.com,1999:blog-9959776.post-89946675158127066682009-08-19T17:17:58.455+01:002009-08-19T17:17:58.455+01:00Gavin Schmidt has pointed out that essentially all...Gavin Schmidt has pointed out that essentially all strong amplification is found over ocean, at least in the GISS model. (Of course, this makes intuitive sense as soon as it's raised).<br /><br />Now if you look at K et al's response incorporating estimated factors from GISS, you see better agreement between HadCRU (amplified) and sats over land than over ocean (and of course globally). So not only is the effect greatly reduced, it's hard to argue that the discrepancy between expected and observed amplification is due to "bias" over land. <br /><br />The large discrepancy between UAH and RSS should also give pause. It's difficult to draw any conclusions about the genesis of sat-surface discrepancies while that equally large discrepancy remains unresolved. And other estimates of tropospheric temperature (Fu, Vinnikov) are even higher than RSS.<br /><br />Finally, not only did K et al not use a reasonable amplification factor for land, but they also did not account for the inherent uncertainty in the estimate of amplification. A more cogent analysis would follow the lead of past analyses by Santer et al and compare model mean amplification with observed, properly taking into account the various uncertainties.Deep Climatehttps://www.blogger.com/profile/07739846320319167391noreply@blogger.com