Thursday, December 8, 2011


From: "Michael E. Mann" <>
Subject: problem
Date: Wed, 04 Apr 2001 14:10:07 -0400

Phil et al,

There is a problem w/ figure 4 (and discussion thereof) in your paper to
appear in Science. Unfortunately, I didn't catch this until I re-read the
paper just now. You haven't shown the right Mann et al NINO3
reconstruction. Are you sure you have used the *cold-season* NINO3
reconstruction, as discussed (and available) in the Mann et al Earth
Interactions paper, and not the annual mean reconstruction!!

I don't believe that has the trend that the series you show does. That
NINO3 series agrees closely (r=0.63) w/ the Stahle et al series (once
the sign has been flipped on that series, and the off-by-one-year date
convention is taken into account), far closer than
what you have shown. I'm pretty sure you've used the wrong series.

Moreover, it is inappropriate to refer (as you do) the Nino3 reconstruction
as an SOI reconstruction, no matter whether it has been
renormalized, sign-switched, etc. There are fundamennal differences between
the low-frequency behavior of NINO3 and SOI, (consider
for example the 20th century!) and they aren't dynamically equivalent! To
say there is a "long-term trend" in our "SOI reconstruction"
is extremely misleading. There is a long-term trend in our *NINO3*
reconstruciton. Only Stahle produced an SOI reconstruction, and it is only
meaningful to correlate the two at annual timescales where they should
similarly reflect largely interannual ENSO variability.

Moreover, I don't think this is true (or as true) of our colld-season NINO3
series, which is the right one to use. Hopefully, you still
have a chance to change this in the galleys, etc.

Thanks in advance for your attention to this,


Professor Michael E. Mann
Department of Environmental Sciences, Clark Hall
University of Virginia
Charlottesville, VA 22903
e-mail: Phone: (804) 924-7770 FAX: (804) 982-2137


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