Friday, December 30, 2011


From: Kevin Trenberth <>
To: Grant Foster <>
Subject: Re: FW: 2009JD012960 (Editor - Steve Ghan):Decision Letter
Date: Mon, 28 Sep 2009 14:45:18 -0600
Cc: Mike Mann <>,, "J. Salinger" <>, James Annan <>,, Gavin Schmidt <>,

Hi all
About time. Incidentally i gave a copy to Mike McPhaden and discussed it with him last
week when we were together at the OceanObs'09 conference. Mike is President of AGU.
Basically this is an acceptance with a couple of suggestions for extras, and some
suggestions for toning down the rhetoric. I had already tried that a bit. My reaction is
that the main thing is to expedite this. That means no extras unless it really makes
sense. And removal of a few unnecessary words like "absolutely".
In the abstract, we have a number of such adjectives that could be removed: I agree with
Rev 3 in this.
"greatly overstates" could be just "overstates" as it is reinforced better later.
"severely overestimates" could be just "overestimates"
"faulty analysis" maybe "flawed analysis"?
"extremely high" maybe "very high" or "unduly high"
I would leave last sentence alone though as the main comment.
A few more comments embedded below.
Grant Foster wrote:

> From: [1]
> Date: Mon, 28 Sep 2009 15:54:05 +0000
> To: [2]
> Subject: 2009JD012960 (Editor - Steve Ghan):Decision Letter
> CC: [3]
> Manuscript Number: 2009JD012960
> Manuscript Title: Comment on "Influence of the Southern Oscillation on tropospheric
temperature" by J. D. McLean, C. R. de Freitas, and R. M. Carter
> ------------------------------------------------------------------------------
> Reviewer Comments
> Reviewer #1 (Comments):
> This paper does an excellent job of showing the errors in the analytical methods used
by McLean et al. and why their conclusions
> about the influence of ENSO on global air temperature is incorrect.
> I have only a couple of suggestions to help clarify their analysis of the methods.
First, a little more explanation of the comment about the time derivative reduced to an
additive constant would help. Second, in the analysis of the artificial time series I
think it would be interesting to show the results of both steps of filtering (running
mean and derivative) as separate time series. This would help the reader understand why
the filtering creates false correlations. The only other suggestion is to find a better
adjective than "faulty" in the abstract to characterize the analysis.

It is not so easy to see the result from the derivative owing to the phase shift. The
spectrum actually does a better job. I would address this comment in this way and change

> Reviewer #2 (Comments):
> I think this comment on McLean et al can be published more or less as is.
> I have two comments
> First, in the abstract (page 3, line 15), I'm not sure that "inflating" is quite the
right verb - the paper itself does not make the point that the filter constructed by
McLean et al inflates power in the 2-6 year window. Perhaps "isolating" would be a
better verb.

Yes it should not be in abstract if not in text. Need to point out that the response
function in Fig. 1 is greater than unity and does "inflate". So adjust the text.

> Secondly, I think the points that are being made with Figures 4 and 5 could be
strengthened by adding to the right of each plot of a pair of time series, a scatter
plot of the pairs of values available at each time. Such a scatter plot would help to
clearly illustrate the absence (upper panels) or presence (lower panels) of correlation
between red and black values.

I don't think this helps. There is nothing to be gained from a scatter plot that a
correlation or regression value does not summarize.

> Reviewer #3 (Comments):
> Accept pending major changes (mainly in style not scientific comment)
> The real mystery here, of course, is how the McLean et al. paper ever made it into
JGR. How that happened, I have no idea. I can't see it ever getting published through J
Climate. The analyses in McLean et al. are among the worst I have seen in the climate
literature. The paper is also a poorly guised attack on the integrity of the climate
community, and I guess that is why Foster et al. have taken the energy to contradict its
> So the current paper (Foster et al.) should certainly be accepted. Someone needs to
address the science in the McLean et al paper in the peer-reviewed literature. But the
current paper could be - and should be - done better. That's why I am suggesting major
changes before the paper is accepted. All of my suggestions have to do more with the
tone and framing of the current paper, rather than its content.
> 1. As noted above, I agree McLean et al is problematic. But as it is written, the
current paper almost stoops to the level of "blog diatribe". The current paper does not
read like a peer-reviewed journal article. The tone is sometimes dramatic and sometimes
accusatory. It is inconsistent with the language one normally encounters in the
objectively-based, peer-reviewed literature. For examples....
> - In the abstract: Do you really need all of these adjectives?...'greatly overstates';
'severely overestimates'; 'faulty analysis'; 'extremely high'.

Agree, see above

> - In the introduction... 'Unfortunately, their conclusions are seriously in error..."
strikes me as overly subjective. Better to say: 'We will demonstrate that their
conclusions are strongly dependent on ....' or something like that...

Don't go that far. Could drop "seriously" but they are "in error"

> - Page X-6: 'tell us absolutely nothing'. Surely it's enough to state 'tell us


> - Page X-9: 'it is misleading...' That's a strong word. It may be true. But I think we
should rise above such accusations.

misleading is OK. I did a search (not sure I have latest) and found "grossly misleading"
and the "grossly" could be removed.

> Anyway, I'm sure the lead author gets my point. I think the current paper will have a
much greater impact (and can claim the high road) if it is rewritten in a more objective
> 2. Similarly, instead of framing the paper as "Taking down McLean et al.", why not
focus more on interesting aspects of the science, such as the frequency dependence
between ENSO and global-mean temperature (perhaps cross-correlation analysis would be
useful); the importance of not extrapolating results from one timescale to another
timescale; or the lack of trends in ENSO. That way, the current paper contributes to the
peer-reviewed literature while also doing a service by highlighting the problems with
McLean et al.

I think I tried to emphasize that this should be a teaching moment. Even more important
given the time lapse.

> 3. In general, the current paper is sloppy and needs tightening. I don't think the
lead author needs 10 pages of text to make the main points.

So over to you to generate the next draft.

Kevin E. Trenberth e-mail: [4]
Climate Analysis Section, [5]
P. O. Box 3000, (303) 497 1318
Boulder, CO 80307 (303) 497 1333 (fax)

Street address: 1850 Table Mesa Drive, Boulder, CO 80305



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