Category Archives: bristlecones

North and NAS on Bristlecones

BTW, I thought that the Chronicle colloquy was pretty interesting. I don’t usually get to ask people questions directly, so I appreciated that the Chronicle allowed questions through without Gavin Schmidt/realclimate censoring. Now that I think of it, the only other question that I’ve been able to ask a climate scientist directly was to Caspar […]

bender on Gaspé

New poster bender has written some very thoughtful posts, including some comments on Gaspé which I I’d like to recover from deep in a political thread. The growth pulse in Gaspé cedars seemed very improbable to me as a temperature proxy; bender has some detailed knowledge on the topic.

Bristlecones, Foxtails and Temperature

The relationship of bristlecone/foxtails to gridcell temperature is something that I’ve discussed at length, but, surprisingly, I’ve never illustrated it at the blog. This is a type of relationship that, in some ways, is well suited to blogs. It’s simple to discuss; it’s important. It would be amply illustrated and discussed in business feasibility studies […]

Graumlich Archives Two Foxtail Series

The two “lost” Graumlich foxtail series used in Esper et al 2002 were archived today at WDCP. Only the specific series that I had requested were archived; other series in Bunn et al 2005 were not archived – see prior discussion here. UPDATE May 17: Graumlich also archived two chronologies (Boreal -ca636.crn; Upper Wright – […]

5 Niwot Ridge Chronologies

As I mentioned earlier today, Niwot Ridge is about 45 minutes drive from UCAR headquarters in Boulder (which hosts the IPCC WG1 TSU). I’ve identified 5 archived chronologies from Niwot Ridge, including two chronologies discussed in Kienast and Luxmoore 1988 as contradicting Graybill’s claims of enhanded post-1950 growth. Graumlich 1991 distinguished the two studies on […]

Rocky Mountain High #2

Pat Frank thought that I was being a little sarcastic of the rigors of updating tree ring collections at Niwot Ridge. However, I’d like now to give what is perhaps a better example of what Mann had in mind when he explained the inability of paleoclimatologists to update tree ring collections. Just to review, here’s […]

Rob Wilson on Bristlecones

Rob Wilson sent in a post on another thread arguing that bristlecones are not as bad a proxy as I would have everyone believe. Unlike realclimate, opposing views are not censored here. In fact, I’m happy to highlight them. I’ll read Rob’s note and reply on an another occasion. I’ll only note now that, in […]

Millar et al: The Sierra Nevada MWP

Otto-Bliesner asked me how I would do a reconstruction. As I’ve said on other occasions, I said that I didn’t know. I’m really reluctant to just apple-pick some series but it’s prbably worthwhile showing that you can pick apples as well as cherries. More constructively, I think that there are some approaches that look better […]

D’Arrigo et al. on Bristlecone Calibration

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 […]

Review of Osborn and Briffa [2006]

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 […]

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