Date: 16 Nov 1999, Phil I’ve just completed Mike’s Nature trick of adding in the real temps to each series for the last 20 years (ie from 1981 onwards) amd from 1961 for Keith’s to hide the decline. Date: 22 Dec 2004, mike No researchers in this field have ever, to our knowledge, “grafted […]
The 20th century warming counters a millennial-scale cooling trend which is consistent with long-term astronomical forcing. MBH99 According to the UMass researchers, the 1,000-year reconstruction reveals that temperatures dropped an average of 0.02 degrees Celsius per century prior to the 20th century. This trend is consistent with the “astronomical theory” of climate change, which considers […]
Here’s a first attempt at applying the techniques of Brown and Sundberg 1987 to MBH99. The results shown here are very experimental, as I’m learning the techniques, but the results appear very intriguing and to hold some possibility for linking temperature reconstructions to known statistical methodologies – something that seems more scientifically useful than “PR […]
%%%% Matlab version of Hockey Stick % %Mann, M. E., R. S. Bradley, and M. K. Hughes (1998), Global-scale %temperature patterns and climate forcing over the past six centuries, %Nature, 392, 779– 787. % %Mann, M. E., R. S. Bradley, and M. K. Hughes (1999), Northern %Hemisphere temperatures during the past millennium: Inferences, uncertainties, %and […]
UC and Hu McCulloch have been carrying on a very illuminating discussion of statistical issues relating to calibration , with UC, in particular, drawing attention to the approach of Brown (1982) towards establishing confidence intervals in calibration problems. In order to apply statistical theory of regression , you have to regress the effect Y against […]
If someone felt that it was necessary to detrend the bristlecone pine-based PC1 of Mann’s AD1000 network for CO2 fertilization, it’s doubtful that the initial instinct would be to coerce the data to a network of northern Canadian-Alaskan tree ring chronologies where the possibility of regional differences must surely be allowed for. Inspection of Mann’s […]
We’ve all had enough experience with the merry adjusters to know that just because someone “adjusts” something doesn’t necessarily mean that the adjustment makes sense. A lot of the time, the adjuster arm waves through the documentation and justification of the adjustment. Today I’m going to work through aspects of one of the most problematic […]
Update: the following does not explain the Caramilk secret of MBH99 confidence intervals, which remains unexplained and mysterious. End Update. OK, Mann starts with a sigma obtained from the standard errors in the calibration period from his hugely overfitted model. He uses this in MBH98. In MBH99, recognizing the autocorrelation in the residuals, he adjusts […]
I’ve posted in the past on the mystery of MBH confidence interval calculations, especially the mysterious MBH99 confidence intervals (another Caramilk secret). In our NAS panel presentation and perhaps before, I’d speculated that MBH98 confidence intervals, rotundly described in MBH98 as “self-consistently estimated” were nothing other than twice the standard error of the (overfitted) calibration […]
Climate Audit 