Comments on: New CPD Paper on Reconstructions http://climateaudit.org/2006/10/26/new-cpd-paper-on-reconstructions/ by Steve McIntyre Tue, 21 May 2013 15:32:22 +0000 hourly 1 http://wordpress.com/ By: jae http://climateaudit.org/2006/10/26/new-cpd-paper-on-reconstructions/#comment-67651 Fri, 17 Nov 2006 17:59:36 +0000 http://www.climateaudit.org/?p=875#comment-67651 65: Thanks. The problem is that there is little or no data for the other variables. In fact, as I understand the situation, they are not even using the correct (local) data for the temp. variable.

]]> By: bender http://climateaudit.org/2006/10/26/new-cpd-paper-on-reconstructions/#comment-67650 Fri, 17 Nov 2006 17:42:03 +0000 http://www.climateaudit.org/?p=875#comment-67650 Re #64
1. No, because I am not stating a proven fact. I am asking a provocative question.
2. If one could identify the top 4 factors and quantify their influence (including interactions), reconstruction might be possible through a simulation approach, rather than a statistical approach. (If the top 4 factors account for much of the variability in an experimental setting, the reconstruction might be quite good.)
3. However you are definitely catching my point. If a four-factor model with interactions is what is required to explain 80% of the variation in growth, then this might explain why a one-term linear model that “explains” 10% of the variability might be inadequate. That is why it is important that the Rob Wilsons, the Martin Juckeses & co-authors address this point.
4. My question is directed specifically at California bcps, not all trees in general (although it may have broader relevance for other species in other systems).

]]> By: jae http://climateaudit.org/2006/10/26/new-cpd-paper-on-reconstructions/#comment-67649 Fri, 17 Nov 2006 17:06:33 +0000 http://www.climateaudit.org/?p=875#comment-67649 Bender: Don’t your comments in #7 suggest that the use of tree rings as temperature proxies is futile? Too many variables and interactions? You have only listed a few out of many other variables, also.

]]> By: bender http://climateaudit.org/2006/10/26/new-cpd-paper-on-reconstructions/#comment-67648 Fri, 17 Nov 2006 15:17:26 +0000 http://www.climateaudit.org/?p=875#comment-67648 Dr. Juckes,
Your attention is requested on #7.

]]> By: TAC http://climateaudit.org/2006/10/26/new-cpd-paper-on-reconstructions/#comment-67647 Mon, 06 Nov 2006 13:41:50 +0000 http://www.climateaudit.org/?p=875#comment-67647 Martin Juckes: As I mentioned in #53, citing Hosking (1984) was welcome, but the discussion in the CPD paper is entirely unsatisfactory. My suggestion would be to read with care some of the recent work on this topic: P Craigmile et al. ["Trend assessment in a long memory dependence model using the discrete wavelet transform," Environmetrics 15, 313-335, 2004]; M Kallache et al. ["Trend assessment: applications for hydrology and climate research," Nonlinear Processes in Geophysics 12:201-210, 2005]; D Koutsoyiannis ["Nonstationarity versus scaling in hydrology," Journal of Hydrology 324, 239-254, 2006], and the various papers cited therein.

Here is the gist: Most papers on climate trends employ demonstrably inappropriate methods. The conventional assumption of iid data, or at most AR(1) or ARMA(p,q) [p and q small], are inconsistent with what one sees in virtually any long time series of climate data (proxy or real). This has been known for over 50 years [Hurst, 1951]. One consequence is that the standard trend tests greatly overstate trend significance, typically with errors that can best be described as huge (e.g. here).

I do not fully understand what was done in the CPD paper, so I am not sure how to comment on it. However, I can state that what appears in the appendix does not inspire confidence. Specifically, the right way to handle this situation does not involve reproducing the sample pacf out to lag 70 or 100.

There really is a better way; see references above, or, even better, consult a statistician familiar with this topic.

]]> By: Willis Eschenbach http://climateaudit.org/2006/10/26/new-cpd-paper-on-reconstructions/#comment-67646 Sun, 05 Nov 2006 22:18:16 +0000 http://www.climateaudit.org/?p=875#comment-67646 Yeah, it’s the weekend, but the site’s been open for comments for ten days now.

w.

]]> By: MarkR http://climateaudit.org/2006/10/26/new-cpd-paper-on-reconstructions/#comment-67645 Sun, 05 Nov 2006 21:51:31 +0000 http://www.climateaudit.org/?p=875#comment-67645

a ban on celebrating “bonfire night’?

Hi Kevin, I think they already banned burning the Guy in some places.

]]> By: KevinUK http://climateaudit.org/2006/10/26/new-cpd-paper-on-reconstructions/#comment-67644 Sun, 05 Nov 2006 21:21:07 +0000 http://www.climateaudit.org/?p=875#comment-67644 #58, Mark R

Shouldn’t that be post the Stern review.

“Several pennies for the Goverment, guy?”

Given that bonfires contribute to CO2 in the atmosphere and therefore to global warming, I wonder how long it will be before our eco-infiltrated, nannying, political correct government introduces a ban on celebrating ‘bonfire night’?

KevinUK

]]> By: MarkR http://climateaudit.org/2006/10/26/new-cpd-paper-on-reconstructions/#comment-67643 Sun, 05 Nov 2006 21:11:52 +0000 http://www.climateaudit.org/?p=875#comment-67643 It’s the weekend, some people have other non-work related things on their minds.

Over here it’s Bonfire Night.

Penny for the Guy Gov?

]]> By: Willis Eschenbach http://climateaudit.org/2006/10/26/new-cpd-paper-on-reconstructions/#comment-67642 Sun, 05 Nov 2006 20:25:29 +0000 http://www.climateaudit.org/?p=875#comment-67642 As of this morning, I’m the only person to comment on the MITRIE paper at CPD, go figure.

I asked a couple of pointed questions of Martin, no reply. Likely he’s busy … but I sure hope the “Discussion” part of CPD is more lively than it has been to date …

w.

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