From	Michael E. Mann	Date	Tue, 28 Jan 2003 12:33:35 -0500
To	Ulrich Cubasch
CC	Tim Osborn, Keith Briffa, Irina Fast, Scott Rutherford, Michael E. Mann
Subject	Re: multiproxy
Dear Ulrich, That's fine--you can go ahead and use it. But I have to issue a number of caveats first. This is a version we gave Tim Osborne when he was visiting here, and since Tim hasn't used it, and we haven't compared results from that code w/ our published results, I can't vouch for it--it may or may not be the exact same version we ultimately used, and it may or may not run properly on platforms other than the one I was using (Sun running ultrix). Scott Rutherford (whom I've cc'd on this email) has worked with the code more frequently. The code is not very user friendly unfortunately. For example, the determination of the optimal subset of PCs to retain is based on application of the criterion described in our paper, which involves running the code many times w/ different choices. So the "iterative" process has to be performed by brute force. The method, as outlined, is quite straightforward and others have implemented it themselves. SO you might prefer to code it yourself. That would be my suggestion. But you are, of course, free to use our code. That having been said, we have essentially abandoned that method now in favor of a somewhat more sophisticated version of the approach, which makes use of the RegEM method for imputing missing values of a field described by Schneider (J. Climate, 2000). Some initial results are described here: Mann, M.E., Rutherford, S., Climate Reconstruction Using 'Pseudoproxies', Geophysical Research Letters, 29 (10), 1501, doi: 10.1029/2001GL014554 [1]ftp://holocene.evsc.virginia.edu/pub/mann/Pseudoproxy02.[2]pdf and in a paper in press in Journal of Climate. Rutherford, S., Mann, M.E., Delworth, T.L., Stouffer, R., The Performance of Covariance-Based Methods of Climate Field Reconstruction Under Stationary and Nonstationary Forcing, J. Climate, in press, 2003. (I don't have the preprint--Scott Rutherford can provide you with one however). In our view, this is a preferable approach on a number of levels, though the results obtained are generally quite similar. I will be in Nice, and looking forward to seeing you there, Mike At 04:59 PM 1/28/03 +0100, Ulrich Cubasch wrote: Dear Michael, as you might know we (Briffa, Wanner, v. Storch, Tett ...) have an European project called SOAP, which aims at combining multy proxi and model data. more under [3]http://www.cru.uea.ac.uk/cru/projects/soap In the workpackage I am coordinating we would like to use your multi-proxy program for some temperature reconstructions. The collegues in Norwich have got your program already, but I would like to implement it here in Berlin. I therefore would like to ask you if you can grant me the permission to use it. I will probably copy it then from Keith and Tim directly. I will keep you informed about the results we obtain with it. regards Ulrich Cubasch P. S. Are you coming to Nice? _______________________________________________________________________ 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 [4]http://www.evsc.virginia.edu/faculty/people/mann.[5]shtml References 1. ftp://holocene.evsc.virginia.edu/pub/mann/Pseudoproxy02.pdf 2. ftp://holocene.evsc.virginia.edu/pub/mann/Pseudoproxy02.pdf 3. http://www.cru.uea.ac.uk/cru/projects/soap 4. http://www.evsc.virginia.edu/faculty/people/mann.shtml 5. http://www.evsc.virginia.edu/faculty/people/mann.shtml