tag:blogger.com,1999:blog-16612221.post7246690897344225888..comments2024-03-19T03:14:04.172-04:00Comments on Rabett Run: The Ice Melts at MidlightEliRabetthttp://www.blogger.com/profile/07957002964638398767noreply@blogger.comBlogger12125tag:blogger.com,1999:blog-16612221.post-47937731922880642432012-11-20T09:43:08.256-05:002012-11-20T09:43:08.256-05:00You'd have to look at the annual cycle in temp...You'd have to look at the annual cycle in temperature in the arctic to know if there is any appreciable effect of the annual cycle in CO2.<br /><br />The response of air temperature to change in forcing is not instantaneous, so the real question becomes "is the response fast enough to have an effect on such a short time scale?"<br /><br />The upper troposphere might respond quickly, but the air immediately above the ice (and open water) would take longer to heat up, so a brief change in forcing due to annual CO2 cycle may not even show up in the surface air temperature.<br /><br />Or perhaps the effect is actually indirect, with cloud cover being affected (reduced due to warming of the upper troposphere) which in turn affects the amount of sun reaching the surface.<br /><br />~@:><br />Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-53066550795245395382012-11-20T07:17:48.147-05:002012-11-20T07:17:48.147-05:00I've had a peek at some files at PCMDI and Wil...I've had a peek at some files at PCMDI and William appears to be correct that all the standard runs use one global value for CO2 concentration in all grid squares.<br /><br />However, CMIP5 includes some 'ESM' experiments for models with interactive carbon cycles. In these realisations CO2 concentrations are regulated by the climate live in the model, so you do get geographically-heterogeneous values and seasonal cycles. A few things from this, just looking at a single annual cycle:<br /><br /> - In the model the difference from peak to trough in the seasonal cycle (monthly resolution) at Barrow's latitude is ~17ppm. However, the amplitude actually decreases from there to the Pole, where it is ~12ppm.<br /><br />- In the model the higher amplitude does not carry vertically. In the upper troposphere it is closer to ~7ppm.<br /><br />These two factors mean the radiative forcing change is not quite as simple as stated in the post, and the ~0.2 figure is likely an overestimate.<br /><br />As a general point, the seasonal change in downwelling shortwave radiation around the Arctic is something like 400 W/m^2 from peak to trough. Seems to me the CO2-cycle effect is a few orders of magnitude too small to make a noticable difference.Paul Shttps://www.blogger.com/profile/15275182941476518621noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-34848484148403215472012-11-20T01:05:47.447-05:002012-11-20T01:05:47.447-05:00using unconventional maths again.
Is this a case ...using unconventional maths again.<br /><br />Is this a case of 'as we can't model plants/animals perfectly, let's leave the effects they seasonally produce out of the model.'? That 20ppm annual cycle is about what, 8 years of anthropogenic emissions? Well ok, statistics says one has to take (missing the link to Tamino) c.16 years of data in order to find out if the Globe has warmed, so the equivalent of 8 years of local anthro emissions has no effect on the conlusion. So, do we always have 8 years to pray for a miracle? That's conveniently 2 election cycles so everything fits. :-(.jyyhhttp://erimaassa.blogspot.finoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-30585964301360291272012-11-19T12:10:39.319-05:002012-11-19T12:10:39.319-05:00Water vapor is intrinsically in the models as rela...Water vapor is intrinsically in the models as relative humidityEliRabetthttps://www.blogger.com/profile/07957002964638398767noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-49456853462766008172012-11-19T10:39:20.041-05:002012-11-19T10:39:20.041-05:00Likewise, there is now some seasonal CH4 (not incl...Likewise, there is now some seasonal CH4 (not included in models). see for example https://sites.google.com/site/apocalypse4realmethane2012/home/2012-vs-2011-airs-ch4-359-hpa<br /><br />And, for the last few summers, there was some H2O vapor (that is not in the models).<br /><br />Aaronhttps://www.blogger.com/profile/05150805906414546377noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-81972461629231107112012-11-19T08:45:29.281-05:002012-11-19T08:45:29.281-05:00Wm. the mixing is slow enough that regional diffe...Wm. the mixing is slow enough that regional difference appear in the column even on an annual scale which is where this guess came from. Certainly the ML annual cycle as opposed to the lack of a cycle shows this as do the differences btw NH and SH. True, your column has to have a pretty wide base. . <br /><br />EliRabetthttps://www.blogger.com/profile/07957002964638398767noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-16195891736752060862012-11-19T07:56:06.606-05:002012-11-19T07:56:06.606-05:00Yes, but though the circulation is quick, the midn...Yes, but though the circulation is quick, the midnight sun is slow to set , amplifying the seasonal impact on regional temperature THE CLIMATE WARShttps://www.blogger.com/profile/02578106673226403151noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-9873422328922389402012-11-19T05:46:46.610-05:002012-11-19T05:46:46.610-05:00Its an interesting point. The models certainly don...Its an interesting point. The models certainly don't bother with location-dependent CO2.<br /><br />I doubt it matters. If the atmosphere was a collection of single columns, it might. Since it isn't, and the circulation is quick, my guess would be the effect is too small to bother with.William M. Connolleyhttps://www.blogger.com/profile/05836299130680534926noreply@blogger.comtag:blogger.com,1999:blog-16612221.post-12964934895978916352012-11-19T02:00:02.574-05:002012-11-19T02:00:02.574-05:00http://oai.dtic.mil/oai/oai?verb=getRecord&met... http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA082453Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-2624930170198708962012-11-19T01:47:31.353-05:002012-11-19T01:47:31.353-05:00well not quite: http://www.jstor.org/discover/10.2...well not quite: http://www.jstor.org/discover/10.2307/1934472?uid=3737976&uid=2&uid=4&sid=21101394971941Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-3063447617299985532012-11-19T01:17:40.627-05:002012-11-19T01:17:40.627-05:00That's been known for almost like ummm.. since...That's been known for almost like ummm.. since Anthony Watts was born. I don't know if a plea for incompetence is enough if that hasn't been factored in. Reason: more active greenery at low latitudes.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-16612221.post-7865562409828292682012-11-18T23:59:44.680-05:002012-11-18T23:59:44.680-05:00Thanks Eli.
Limit cooling in the winter: maybe de...Thanks Eli.<br /><br />Limit cooling in the winter: maybe delays some winter ice formation?<br />Increase melting in the spring: start the death spiral earlier?<br />Less melting in late summer? Huh?<br /><br />You ought to ask over on Real Climate whether the models include this interesting observation.David B. Bensonhttps://www.blogger.com/profile/02917182411282836875noreply@blogger.com