cc: Scott Rutherford , mann@virginia.edu date: Mon, 19 Jan 2004 15:59:36 -0500 from: "Michael E. Mann" subject: Re: J. Climate paper - in confidence to: "Malcolm Hughes" , "Malcolm Hughes" , Tim Osborn , Briffa Keith Malcolm, series (5) is 'trd.dat', a Bradley & Jones (93) series. BJ93 was of course the nucleus of the MBH98 network, which was constructed by adding other indicators to that initial dataset. Of course, that does imply some redundancy, since many of the BJ93 series were composites of other data, etc. I might have gotten the reference from BJ93 for trd.dat wrong (Fritts and Shao is for correct for trw.dat, but perhaps not trd.dat, right?). I don't have BJ93 w/ me? What reference does it give for trd.dat? Scott should fix this in the revised MBH98 data list: [1]ftp://holocene.evsc.virginia.edu/pub/sdr/temp/nature/MANNETAL98/PROXY/mbh98datasummary.t xt In any case, this hardly constitutes "considerably more overlap". This represents 1 series/indicator out of 415 series/112 indicators used. So, in total, there are 24 density series used out of a total of 415 proxy indicators, in the MBH98 network. Its fair to say this comprises a "very small fraction" of the network, but of course we must be careful to point out that the two networks are therefore not entirely independent. I will modify the wording in the paper accordingly. One final question, was each of the 24 density series in question actually used in the Briffa et al MXD network (Tim/Keith?). Thanks all for the feedback, mike At 01:42 PM 1/19/2004 -0700, Malcolm Hughes wrote: Mike - there are the following density data in that set: 1) 20 Schweingruber/Frttss series from the ITRDB (those that met the criteria described in the Mann et al 2000 EI paper) 2) Northern Fennoscandia reconstruction (from Keith) 3) Northern Urals reconstruction (from Keith) 4) 1 density series for China (Hughes data) and one from India (also Hughes data) - neither included in Keith's data set, I think. 5) To my great surprise I find that you used the Briffa gridded temperature reconstruction from W. N. America (mis-attributed to Fritts and Shao) - of course I should have picked up on this 6 years ago when reading the proofs of the Nature sup mat. It was my understanding that we had decided not to use these reconstructions, as the data on which they were based were in the ITRDB, and had been subject to that screening process. So depending on whether you used the long or the shorter versions of these, there will have been a considerable number of density series included , some of them twice. It means that there is considerably more overlap between the two data sets, in North America, than I have been telling people. I stand corrected. Cheers, Malcolm . .Malcolm Hughes Professor of Dendrochronology Laboratory of Tree-Ring Research University of Arizona Tucson, AZ 85721 520-621-6470 fax 520-621-8229 ______________________________________________________________ Professor Michael E. Mann Department of Environmental Sciences, Clark Hall University of Virginia Charlottesville, VA 22903 _______________________________________________________________________ e-mail: mann@virginia.edu Phone: (434) 924-7770 FAX: (434) 982-2137 [2]http://www.evsc.virginia.edu/faculty/people/mann.shtml