Category Archives: Divergence

Devi et al 2009

See comments introducing this extremely interesting article. UPDATE: Since some readers are having routing issues downloading/reading this Devi et al paper, I have mirrored it here (PDF) for your convenience. – Anthony

Craig Loehle on the Divergence Problem

Tree rings are widely used for reconstructing climate and past climates are critical for putting the current climate (including global temperatures) into the proper perspective. Is current warming unusual? Only a comparison to the past can tell. To help gain a better understanding of the past and how global temperatures may have behaved, researchers frequently […]

Divergence: the Young Dendros Rebel

I’ll try to do reports on various interesting aspects of the AGU conference over the next few weeks. Today I’m going to post on the session on the Divergence Problem, initiated and chaired by Rob Wilson, and which, for the most part, consisted of young dendros probing critically at the issue of the failure of […]

How IPCC AR4 authors defended the Briffa data deletions

I recently received a copy of how IPCC authors answered the review comments, including their answers to the requirement of one reviewer that the deleted Briffa data be restored (and an explanation given for the inconvenient bits.) You may recall the observation of one reader in the discussion of Swindle, the reader observing: If a […]

New Light on Old Fudge

One of my first blog postings was on Briffa’s very first fudging (2011 update: the “Briffa bodge”) of a temperature reconstruction – his adjustment of the Tornetrask reconstruction – a reconstruction that is used in virtually every study. This was one of the first encounters with the Divergence Problem. Tornetrask MXD went down in the […]

GHCN Adjusted Data Isn't Good Enough for D'Arrigo et al

D’Arrigo, Wilson et al 2007 is an interesting article on the Divergence Problem, about which I plan to post from time to time. Since we’ve been discussing temperature data recently – with special discussions of GHCN data problems in Russia, China and Australia, I thought that it would be interesting to draw attention to an […]

More on the Divergence Problem

Two new things on the Divergence Problem. The IPCC First and Second Drafts did not contain a whisper of a mention of the divergence between ring widths and density in the second half of the 20th century, although this is rather an important issue. It came up at the NAS Panel and was completely unresolved […]

A Reply to an Angry Dendroclimatologist

In a recent post, I challenged the Dendro Truth Squad to root out use of precipitation proxies in multiproxy studies (which the NAS Panel also encouraged avoidance of). Instead of illustrating this with bristlecones one more time (although they obviously occur in a high desert), I illustrated the challenge with the example of Dulan junipers, […]

More on Positive and Negative Responders

(2012 Update…) CA was the first blog to discuss the recent papers by Wilmking and his associates on “positive and negative responders” – the opposite response of trees to recent warming in which – at the same site – some trees responded positively and some negatively. This is an important observation in trying to provide […]

Wilson et al 2007

Rob Wilson has referred us to Wilson et al 2007. In addition to being an example of site selection, Wilson et al 2007 uses a type of principal components on a tree ring network – something that should be of interest to many CA readers – and an interesting illustration of non-Mannian statistical methods within […]

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