A comment on M+W10 submitted to RealClimate.org

I submitted a comment to the RealClimate.org post Doing it yourselves (20 August 2010), as the author makes some interesting remarks on the intersection of McShayne and Wyner (2010) and the Tiljander proxies. My comment entered the moderation queue last night after position #41, and wasn't among the ten comments that have been released in three batches this morning. Perhaps it has been failed, or perhaps it's being delayed. If does make a belated appearance (accompanied with inline commentary?), I'll note that in an update.

[ UPDATE 22 Aug. 2010 3:20 PM EDT -- In the past hour, my comment passed moderation, and was slotted into position #42 (the comment count is currently at 60). Gavin Schmidt's inline commentary is reproduced at the tail of this post. -- AMac ]

The Tiljander Data Series: Data and Graphs

I have compiled the information from the Lake Korttajarvi borehole varved sediments record that was characterized in Tiljander03, and then used in the multiproxy paleoclimate reconstruction Mann08.

The Excel file containing this data can be downloaded from this BitBucket.org archive. The name of the 1.5MB file is Tiljander-Mann08-proxies-data+graphs.xls. The name of the 1.8 MB file is Tiljander_proxies_dataset_graphs.xls .

Some observations and some graphs follow.

Part 2: Synopsis of some Tiljander-related arguments

This post is the continuation of a discussion on the Tiljander proxies that took place in the comments thread following the Aug. 1, 2010 Climate Audit post The No-Dendro Illusion.

Part 1 is here. As with that post, I may clean up formatting and grammar here, without notice.

Unthreaded post

This is a post for comments that don't fit anywhere else on the blog.

Please be civil, etc.

Synopsis of some Tiljander-related arguments in a recent Climate Audit thread

This post is a placeholder that will hopefully be superseded by a more careful and thorough description of a discussion of the use of the four Lake Korttajarvi lakebed sediment series (the "Tiljander proxies") in Mann08 (PNAS). This discussion was largely between two pseudonymous commenters at Steve McIntyre's Climate Audit post The No-Dendro Illusion.

I'm putting this together to respond to this recent comment by DeepClimate, at his blog.

MikeN weighs in on Mann08's use of the Tiljander proxies

One thing that I can't do is evaluate the MatLab code that Prof. Mann placed online when PNAS published Mann08 in September, 2008. I can't even make heads or tails of Steve McIntyre's "R"-based emulations of Mann08... when it comes to running even simple programs, I'm an illiterate (gasp!).

MikeN is a frequent participant at technical Climate Audit discussions. The latest has been The No-Dendro Illusion. He has offered considerable insight within the threads at Arthur Smith's posts at Not Spaghetti considering the use of the Tiljander proxies in the Mann research group's recent efforts: Where's the fraud?, Michael Mann's errors, and Open Thread.

Via email, he offered a summary of his views of Mann08's use of the Tiljander proxies. With minor edits, his remarks follow.

Two views of Tiljander

On Aug. 4 at Collide-a-scape, Keith Kloor presented an e-mail interview of Gavin Schmidt, the NASA climate modeler and RealClimate.org blogger, Gavin's Perspective. It's a generally interesting read. After the post went up, Gavin stayed around to field accodades and brickbats from readers. After some questions about the Tiljander/Mann Affair went unanswered, I penned a Tiljander For Beginners essay at #127, and invited Gavin's thoughts. He duly responded with his view at #188.

The two perspective pieces are side-by-side, below.

Backgrounder on Analysis of Freshwater Lakebed Varved Sediment Cores

Deep in the thread following the Climate Audit post The No-Dendro Illusion, "Ianl8888" made a series of remarks that provide valuable context to the 2003 Boreas paper by Mia Tiljander et al.

His (or her) remarks follow, with minor edits for style.

A Savings Account at the Paleo National Bank

Thanks to my town's Open Meeting Law, I'm able to follow local officials' actions pretty closely. Our Treasurer recently reported that, a few months ago, she switched the town's savings account to the Paleo National Bank. She was attracted by its generous offer of a 6% annual percentage rate. The latest Treasurer's Report included a summary of last month's savings account statement from the PNB. It looked like this:

Beginning-of-month balance: $2,500.00
Deposits: $200.00
Withdrawals: $250.00
Average Daily Balance: $1,841.54
Interest: $6.20
End-of-month balance: $2,443.80.

At first, this looked okay -- but on closer inspection, the arithmetic seemed questionable:

$2,500.00 + $200.00 - $250.00 + $6.20 = $2,456.20

There's a difference of $12.40. It seems that Interest of $6.20 had been debited from rather than credited to the balance:

$2,500.00 + $200.00 - $250.00 - $6.20 = $2,443.80

Tiljander Proxies' Modest Effects on Mann08 Estimates... probably

Few things in life can be as rewarding as shouting "I was wrong!"

[Edit 7/13/10: That is, "probably wrong in thinking that the Tiljander proxies make an oversized contribution to Mann08's paleoclimate reconstructions (and still correct about other Tiljander-related issues)." Elaborated upon, below.]

One of the things that's annoyed Dr. Schmidt (see his Collide-a-scape 'guest post' The Main Hindrance to Dialogue (and Detente)) and other AGW Consensus advocates has been my contention that the Tiljander proxies likely provide a substantial contribution to the "hockey stick" shape of the paleotemperature reconstructions in the Mann group's 2008 PNAS paper, "Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia" (see this post for literature references). That stance has provided grist for the mill for protracted discussions at Lucia's Blackboard and other blogs. But...

Ari Jokimäki Looks at the Tiljander Proxies

This post is a placeholder (29 June 2010). The immediate intent is to provide a link to two sites. This post was written on 29 June 2010; corrections and minor additions made on 7 July 2010 are in italics. The objective is to provide some data and links to accompany recent posts by Ari Jokimäki and Arthur Smith.

First, Ari Jokimäki's new analysis of the Tljander proxies, particularly XRD, X-Ray Density. His post at AGW Observer is Tiljander.

Second, here is a link to the Excel file Kort-gridbox-CRUtemv3.xls, which contains monthly and annual CRUtemv3 CRUTEM3v temperature anomaly records for the 5 degree by 5 degree gridbox that includes Lake Korttajarvi. It is downloadable from Bitbucket by clicking on the filename.

The Newly-Discovered Jarvykortta Proxy -- II

This post is a rewrite of an essay I published on 28 Nov. 2009, The Newly-Discovered Jarvykortta Proxy: Relevant to the Tiljander Varve Series? It's been edited and reformatted for clarity. I assume that a fictional monastery exists alongside a fictional "Jarvykortta River" (cf. the real Lake Korttajarvi) in fictional Ruritania (cf. Finland). The point is to explore whether a proxy series can be inadvertently used in an upside-down orientation. The example illustrates that Yes, such an error is quite possible. I argue that a data series refers back to one or more physical attributes. Care should be taken to see that such data are used in the orientation that makes logical sense, with respect to what they represent in the physical world.

Another Scientist Commends Mann et al. '08 -- Tiljander Notwithstanding

Last week, Roger Pielke Sr. headlined a critical email on his site, Guest Post By Chick Keller On The Content and Tone Of My Weblog. Dr. Keller is the retired Director of the Los Alamos National Laboratory Branch of the University of California’s Institute of Geophysics and Planetary Physics (IGPP). He's made significant contributions to the peer-reviewed literature on climate change (PDF).

While I am not a regular reader of Pielke's blog, such efforts to establish dialog among 'Consensus scientists,' 'skeptics,' and 'lukewarmers' are commendable. Given my own interests, I was most taken by the following paragraph from Chick Keller's post.

The Null Hypothesis

This post is a follow-on to discussions on the use by Mann et al (PNAS, 2008) of the Lake Korttajarvi varve proxies described by Tiljander et al (2003), at Lucia's Blackboard and at Michael Tobis' Only In It For The Gold.

Nick Stokes asserted,

Mann fixed Tiljander in the SI of the 2008 paper. He did an analysis without it. If the calibration of the proxy doesn’t work, that’s all you can do.

This follows in the footsteps of Gavin Schmidt's analysis at RealClimate.org --

[Response: This issue was discussed ad nausem at Stoat - bring it up there... There is no other possible reconstruction that would use the proxy in another orientation. It is either in the way it was, or it isn't included at all. Both options were published together in the PNAS paper. No correction needed... ]

Emphasis added.

In this post, I argue that understanding the implications of Mann et al.'s use of the Lake Korttajarvi varve series is essential to a reasoned interpretation of their work.