I’ve talked recently about the phenomenon of cherry picking tree ring chronologies with upticks in the small-subset (10-20) compilations used in typical Hockey Team multiproxy studies (e.g. Jones et al 1998; Crowley and Lowery 2000, etc., most recently Osborn and Briffa, 2006; and to a slight lesser extent D’Arrigo et al, 2006 (where there was […]
The Polar Urals temperature reconstruction (Briffa et al, 1995) has been a mainstay of multiproxy studies. More data was collected at this site in 1998 (russ176), but in the two new studies (Osborn and Briffa, 2006; D’Arrigo et al., 2006), they relate their site selection to the Polar Urals, but substitute the Yamal RCS series […]
There’s been a relatively lively discussion at realclimate here on O&B . I’ve got a couple of thoughts for now on (1) the independence of authors and (2) differences between datasets – two issues which I’ve frequently discussed.
D’Arrigo, Wilson and Jacoby [2006] represents state-of-the-art in dendrochronology and is hot off the press. It is unique among such studies in using a considerable amount of up-to-date data and is relatively candid about its results. I’ll try to discuss it in more detail. Here I want to pick up on one issue that featured […]
David Stockwell was intrigued by the seeming “robustness” of O&B results. There’s a reason for it: pretty much every one of the stereotyped Hockey Team proxies that are common to multiple studies are included in the O&B collation: bristlecones, Briffa’s re-processed series, Thompson’s Dunde and Guliya, Jacoby’s Mongolia. Pretty much every rascal has been gathered […]
Osborn and Briffa [2006] , published today in Science, cannot be considered as an “independent” validation of Hockey Stick climate theories, because it simply re-cycles 14 proxies, some of them very questionable, which have been repeatedly used in other “Hockey Team” studies, including, remarkably, 2 separate uses of the controversial bristlecone/foxtail tree ring data. Also […]
A recurring question which was asked again on at Eurotrib: in the Wikipedia spaghetti graph, how many of the spaghetti strands are from the Hockey Team? I guess it depends how you define the "Hockey Team". Almost exactly one year ago, I posted up the following listing http://www.climate2003.com/blog/hockey_team.htm of who I thought was on the […]
For your reading pleasure, here is our Reply to Ammann and Wahl (GRL). as submitted on Jan. 29, 2006. You don’t have access to the A&W Comment itself; [update: now here ] but if you re-read the Huybers article, it has the same points without all the mischaracterizations and misrepresentations of A&W. A&W also have […]
I’ve just noticed at the UCAR website that Ammann and Wahl now say that their CC re-submission was “provisionally accepted” on Dec 12. I have no information on what a "provisional acceptance" means, but it’s certainly a coincidence that the “provisional acceptance” occurred only 3 days after GRL agreed to send their previously rejected GRL […]
Continued from Part 1, Part 2, Part 3 OK, back to Ammann at AGU, his answer to the cross-validation R2 and my offer to him after our lunch. I think that asking for the cross-validation R2 was a good one-bite question at several different levels. First, it’s objective and any prevarications are noticeable to the […]
Climate Audit 