From: Kevin Trenberth <trenbert@ucar.edu>
To: Michael Mann <mann@meteo.psu.edu>
Subject: Re: ENSO blamed over warming - paper in JGR
Date: Wed, 29 Jul 2009 10:23:09 -0600
Cc: Grant Foster <tamino_9@hotmail.com>, p.jones@uea.ac.uk, "J. Salinger" <j.salinger@auckland.ac.nz>, j.renwick@niwa.co.nz, b.mullan@niwa.co.nz, Gavin Schmidt <gschmidt@giss.nasa.gov>, James Annan <jdannan@jamstec.go.jp>

   Hi all
   Wow this is a nice analysis by Grant et al.  What we should do is turn this into a learning
   experience for everyone: there is often misuse of filtering.  Obviously the editor and
   reviewers need to to also be taken to task here.  I agree with Mike Mann that a couple of
   other key points deserve to be made wrt this paper.  Making sure that the important
   relationships and role of ENSO on interannual variability of global temperatures should
   also be pointed out with some select references (as in recent emails and the refs
   therein).  In terms of the paper, I recommend consolidating the figures to keep them fewer
   in number if this is a comment: combine Figs 3 with 4 , and 6 with 7.  Make sure the plots
   of spectra have period prominently displayed as well as frequency and maybe even highlight
   with stipple some bands like >10 years.  Glad to sign on: I would need an acknowledgment
   that NCAR is sponsored by NSF.
   Regards
   Kevin
   Michael Mann wrote:

     thanks Grant, the paper is starting to shape up well now. Jim and I (well, mostly Jim,
     w/ some input from me) are iterating on a blurb about past studies on ENSO/temperature
     relationships and should have something for you soon on that,

   As James has pointed out, its important to stick to the key points and not get sidetracked
   with nonsense. I would avoid any commentary on their ignorant ramblings about the Hadley
   Cell, etc.  We want to cut straight to the deep flaws in their analysis which are, in order
   of importance in my view,

   1. indefensible use of a differencing filter, which has the effect of selectively damping
   low-frequency variability and renders any conclusions about factors underlying long-term
   trends completely spurious.

   2. ignoring the fact that the influence of ENSO on global temperature has been known for
   decades, and much better quantified in past studies than in the current deeply flawed
   analysis.

   3. the selective use of a flawed temperature data and curious splicing in of inappropriate
   recent data (UAH TMT) to further suppress trends.  A bit of overkill given that they
   already eliminated the trends anyway. Guess they wanted to play it extra cautious just in
   case some bit of warming trend tried to sneak in.

   The other stuff is just a distraction.

   mike

   On Jul 29, 2009, at 10:51 AM, Grant Foster wrote:

   Gentlemen,
   Attached is a zip file with LaTeX and pdf for a first draft.  I've included everybody's
   name (in alphabetical order after mine), but of course it should only include in submission
   those who give explicit consent.
   There are a few other issues.  One is that MFC have recently removed the pdf version of
   their paper from the "New Zealand Climate Coalition" website.  They've replaced it with
   this:
   [1]http://nzclimatescience.net/index.php?option=com_content&task=view&id=502&Itemid=1
   which refers to a graph showing only part of figure 7, and suggests that there's not trend
   in GTTA so "nothing to worry about."  Yet the plotted GTTA is from UAH TMT (*not* TLT) so
   of course it shows no trend, and the MT channel is contaminated by stratospheric cooling.
   In figure 7 of the paper itself they compare the 50-year record of SOI and GTTA, but their
   graph of GTTA is made of RATPAC-A data until 1980 grafted onto UAH TMT data afterward --
   hence the lack of an obvious trend.  I think this too should be mentioned, especially as
   the entire RATPAC-A record shows a very pronounced trend.
   One last thing: there's a lot of stuff in the paper about Hadley cells and heat transport
   and so forth.  I suspect this is really a bunch of gobbledygook -- but I don't know.  But
   I'll bet you guys do.  Comments?
   Sincerely,
   Grant
     ______________________________________________________________________________________

   Windows Live(TM) HotmailŪ: Celebrate the moment with your favorite sports pics. [2]Check it
   out. <comment.zip>

   --
   Michael E. Mann
   Professor
   Director, Earth System Science Center (ESSC)
   Department of Meteorology                 Phone: (814) 863-4075
   503 Walker Building                              FAX:   (814) 865-3663
   The Pennsylvania State University     email:  [3]mann@psu.edu
   University Park, PA 16802-5013
   website: [4]http://www.meteo.psu.edu/~mann/Mann/index.html
   "Dire Predictions" book site:
   [5]http://www.essc.psu.edu/essc_web/news/DirePredictions/index.html

--
****************
Kevin E. Trenberth                  e-mail: [6]trenbert@ucar.edu
Climate Analysis Section,           [7]www.cgd.ucar.edu/cas/trenbert.html
NCAR
P. O. Box 3000,                     (303) 497 1318
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Street address: 1850 Table Mesa Drive, Boulder, CO  80305

References

   1. http://nzclimatescience.net/index.php?option=com_content&task=view&id=502&Itemid=1
   2. http://www.windowslive.com/Online/Hotmail/Campaign/QuickAdd?ocid=TXT_TAGLM_WL_QA_HM_sports_photos_072009&cat=sports
   3. mailto:mann@psu.edu
   4. http://www.meteo.psu.edu/%7Emann/Mann/index.html
   5. http://www.essc.psu.edu/essc_web/news/DirePredictions/index.html
   6. mailto:trenbert@ucar.edu
   7. http://www.cgd.ucar.edu/cas/trenbert.html

