From	Kevin Trenberth	Date	Mon, 03 Aug 2009 11:34:59 -0600
To	Grant Foster
CC	Phil Jones, Jim Salinger, James Annan, Jim Renwick, Michael E. Mann, Gavin Schmidt, Brett Mullan
Subject	Re: ENSO blamed over warming - paper in JGR
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 ___________________________________________________________________________________ Windows Live(TM): Keep your life in sync. [1]Check it out. -- **************** Kevin E. Trenberth e-mail: [2]trenbert@ucar.edu Climate Analysis Section, [3]www.cgd.ucar.edu/cas/trenbert.html NCAR P. O. Box 3000, (303) 497 1318 Boulder, CO 80307 (303) 497 1333 (fax) Street address: 1850 Table Mesa Drive, Boulder, CO 80305 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