Comments on: Mann 2008 – Replication II

By: Notes on RegEM « Climate Audit

Notes on RegEM « Climate Audit — Mon, 17 Oct 2011 03:08:32 +0000

[...] a period with some interesting properties previously observed some time ago by Jean S and UC here here, but not explained at the [...]

By: UC

UC — Fri, 20 Mar 2009 17:39:38 +0000

I guess Steve will be soon around, so I can email him the zip-files to upload. But for now I uploaded the steps we found most bizarre: Target temperature AD500 proxies, in the following order

nv512 tiljander_2003_darksum tiljander_2003_lightsum tiljander_2003_thicknessmm tiljander_2003_xraydenseave tornetrask tan_2003_recontemp curtis_1996_d13cpyro curtis_1996_d18o burns_2003_socotrad13c burns_2003_socotrad18o dongge

AD500 reconstruction --- AD600 proxies, in the following order

fisher_1996_cgreenland nv512 tiljander_2003_darksum tiljander_2003_lightsum tiljander_2003_thicknessmm tiljander_2003_xraydenseave tornetrask tan_2003_recontemp curtis_1996_d13cpyro curtis_1996_d18o burns_2003_socotrad13c burns_2003_socotrad18o dongge

AD600 reconstruction Proxies and reconstructions are as regreclow.m writes them.

By: David L. Hagen

David L. Hagen — Fri, 20 Mar 2009 13:59:15 +0000

For Freedom of Information Act (FOIA) requests for code and data, see new guidelines by Attorney General Holder:

Attorney General Issues New FOIA Guidelines to Favor Disclosure and Transparency
http://www.usdoj.gov/opa/pr/2009/March/09-ag-253.html

Memorandum for Heads of Executive Departments and Agencies Re The Freedom of Information Act (FOIA)
http://www.usdoj.gov/ag/foia-memo-march2009.pdf

–

By: andy

andy — Fri, 20 Mar 2009 11:35:44 +0000

Thanks, seems that at least some Fisher series have been discussed in CA as well; http://www.climateaudit.org/?p=883

By: Jean S

Jean S — Fri, 20 Mar 2009 07:56:55 +0000

Re: andy (#15), Oh, if you meant the one with the label "curtis_1996_d13cpyro" (which seems to be dominant in AD600 step), that's one of Punta Laguna series (C13.P_coronatus) discussed already here in the context of infilling.

By: Jean S

Jean S — Fri, 20 Mar 2009 07:37:15 +0000

Re: andy (#15),
if you mean the one labeled “fisher_1996_cgreenland”, it is supposedly this one:
http://www.gfy.ku.dk/~www-glac/papers/abstracts/183.htm
It gets weights (AD600) -0.2079 (for the low split; shown above) and -0.1775 (for the high split). It is given ID 8000, which means that in order to pass the screening, it should have positive (pick-two) correlation with the local temperature. Indeed, it has, according to this file the reported (pick-two) correlations are
full screening: 0.3311
late: 0.3742
early: 0.4976

This amazing change between AD500 and AD600 (compare the lower right corners in UC’s update figures) in the reconstruction due to adding a single series is also clearly visible in the final reconstruction (see the second figure in this post). I guess this is what they mean by “robust”.

Notice also that there are FOUR Tiljander series (one switching sign between AD500 and AD600) out of total 12/13 proxies. I guess it must be “bizarre” to wonder how “robust” the reconstruction is for removing those series…

By: andy

andy — Fri, 20 Mar 2009 05:50:16 +0000

Which proxy is this, AD600 step-in, with all upsidedown side effects?

By: Mark T

Mark T — Fri, 20 Mar 2009 04:33:03 +0000

Re: JohnT (#12),

"Yep, Mann is wrong. How could he have made such a huge mistake. Seems like he is losing his MoJo"

Given that this started with Mann's very first (or nearly) paper, I'm guessing none can really say he's "losing" anything. Of course, this also assumes said peers understand the distinctions as well as Jean S or UC themselves.

Are thoughts like this being circulated in the climate community?

Not openly, at least, when was the last time you heard a headline in the MSM stating "statistical conclusions are shown to be unsupported in XXX09" or similar? Mark

By: Michael Jankowski

Michael Jankowski — Thu, 19 Mar 2009 23:24:21 +0000

Re: JohnT (#12), it seems as if their heads are in the sand. He's only one of many climate scientists who do not get statisticians involved in publications that are heavily dependent on statistical methods.

By: JohnT

JohnT — Thu, 19 Mar 2009 23:05:22 +0000

I wonder how many of Mann’s peers secretly read CA, and look at threads like this and say “Yep, Mann is wrong. How could he have made such a huge mistake. Seems like he is losing his MoJo”.

Mann’s statistical skills appear to be “nonrobust” compared to JeanS’s.

Are thoughts like this being circulated in the climate community?