From: Kevin Trenberth <trenbert@ucar.edu>
To: Grant Foster <tamino_9@hotmail.com>
Subject: Re: ENSO blamed over warming - paper in JGR
Date: Mon, 03 Aug 2009 11:34:59 -0600
Cc: p.jones@uea.ac.uk, "J. Salinger" <j.salinger@auckland.ac.nz>, James Annan <jdannan@jamstec.go.jp>, j.renwick@niwa.co.nz, Mike Mann <mann@meteo.psu.edu>, Gavin Schmidt <gschmidt@giss.nasa.gov>, b.mullan@niwa.co.nz

   Hi Grant,
   I have been tied up with other things.  In looking at the paper some questions.
   1) In Fig 1, why is the scale zero to 2?  Normally a filter would be scaled to have a
   response function zero to 1.
   2) In Fig 2 and 3 what are the units of "power"? It is not in the caption.  Are these
   normalized spectra so that the area under the curve is unity?  My guess is that this is the
   case and hence the amplification at ENSO bands.  But it is important to say this and
   perhaps point out.  Maybe the captions are sufficient?   Add something like:  The spectra
   have been normalized to have unit variance, which relatively inflates the values in the 0.2
   to 0.5 frequency band.   In a couple of places in text add "normalized" before "power
   spectrum" such as 2 lines above Fig 3 in the JGR set version.
   3) A minor point: in the  x= sin(2*pi*vt) I would be inclined to add an amplitude which
   would then be included also in eq (1) on RHS emphasizing how the amplitude is changed.
   [My own preference would be to call the amplitude A and the A you have R (for response
   function)].  However it is fine as is.
   Thanks
   Kevin
   Grant Foster wrote:

     Gentlemen,
     Well, I got some free time and it didn't take as long as I expected.  Attached are:
     comment.zip    Comment in preprint form
     draft.zip      Comment in draft form (for submission)
     freeform.zip   Comment NOT as preprint or draft, with larger font and double-wide graphs
     I suggest we don't circulate it until folks have had one further day to check.  And
     double check and triple-check.  If we don't hear an objection by tomorrow morning, I
     suggest we submit it to JGR and feel free to circulate it.
     So -- this is your last chance to suggest changes before submission, or to suggest
     restraint in circulation.
     Sincerely,
     Grant
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Kevin E. Trenberth                  e-mail: [2]trenbert@ucar.edu
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References

   1. http://windowslive.com/explore?ocid=PID23384::T:WLMTAGL:ON:WL:en-US:NF_BR_sync:082009
   2. mailto:trenbert@ucar.edu
   3. http://www.cgd.ucar.edu/cas/trenbert.html

