date: Thu Sep 25 07:59:46 2003
from: Keith Briffa <k.briffa@uea.ac.uk>
subject: Re: your submission to THe Holocene
to: alana@unav.es

   Dear Dr Gil-Alana
   I am terribly sorry , but your email prompted me to check my files and I have now only just
   realised that I did not communicate with you following my last message. Your file was put
   in the wrong drawer.
    I am sorry to say that we have decided not to publish your paper - the overwhelming reason
   being , not a criticism of its general scientific content , but rather the relatively low
   relevance weighting put on it by the referees, with specific regard to this journal. After
   reading their reports , one of which ( ironically the one that took a long time to secure),
   simply emphasised that the readership would not appreciate the significance of the work .
   The other referee made potentially somewhat more substantive comments and these are copied
   below, but the question of relevance was also to the fore. I discussed this with our main
   editor,  John Matthews,  and we agreed that we would have to concur with this opinion,
   particularly given the current heavy load of submissions.
   Of course this decision should have been communicated to you many weeks (even months ) ago
   , and for this I am truly sorry. I hope you accept this apology and will feel able to
   submit the manuscript elsewhere.
   Yours sincerely
   Keith Briffa
   referee 1 comments
   ________________________________________________________________________________
   Review of manuscript "A Global Warming in the Temperatures in the Northern Hemisphere Using
   Fractionally Integrated Techniques",
   author: L.A. Gil-Alana
   This manuscript describes some interesting statistical modeling experiments with the CRU
   instrumental 'Northern hemisphere mean temperature' series of 1854-1989, building on
   previous work by Bloomfield and others.
   The primary problem with this, and other similar past papers of this kind, however, is that
   the wrong null hypothesis is assumed, creating somewhat of a 'straw man' for the argument
   in favor of a long-range dependent noise process. The null hypothesis invoked is that the
   observed NH mean temperature series is a realization of a stationary noise process, and
   that null hypothesis is subsequently rejected in favor of a non-stationary noise process
   (i.e., a fractionally-integrated noise process). The null hypothesis thusly assumed is
   inappropriate however, leading to false conclusions regarding the statistical character of
   the series. It is very likely that at least 50% of the low-frequency variability in the
   series in question is externally forced (by volcanic, solar, and in particular in the 20th
   century, anthropogenic radiative forcing). See e.g.:
   Crowley, T.J., Causes of Climate Change Over the Past 1000 Years, Science, 289 (14 July),
   270-277, 2000.
   The non-stationary (ie., the 20th century trends) in the series in large part arises from
   the linear response of the climate to these forcings, and much of the apparent
   'non-stationarity' is simply a result of the non-stationary nature of the forcings, not the
   non-stationarity of the noise term. Moreover, this associated temporal dependence structure
   is almost certain to change over time, as the emerging anthropogenic forcing increases the
   relative importance of the forced vs. internal (noise) component of variance. See e.g.:
   Wigley, T.M.L., R.L. .Smith, and B.D. Santer, Anthropogenic Influence on the
   Autocorrelation Structure of Hemispheric-Mean Temperatures, Science, 282, 1676-1680, 1998.
   The appropriate null hypothesis (and a challenging one to beat, in my opinion) would be
   that the observed temperature series is the sum of an externally-forced component as
   modeled e.g. by Crowley (the data is available here:
   http://www.ngdc.noaa.gov/paleo/pubs/crowley.html) plus a simple autocorrelated AR(1)
   internal noise process. This is the most physically-plausible model for the observed NH
   mean temperature variations, so the fractionally-integrated process must at the very least
   do better (in a statistical sense) than this model...
   There are a number of other minor problems:
   1) No account is taken of the obvious change in variance (and presumably, the temporal
   dependence structure as well) back in time with increased sampling uncertainty (and
   potentially, bias due to limited spatial representation in the underlying data network) in
   the sparser early observations. For some purposes that isn't a problem. However, in this
   study, where it is precisely the variance and temporal dependence structure of the series
   that is being analyzed, I believe this is a problem.
   2) It looks as if an unnecessarily outdated version of the CRU NH series has been used. A
   revised, and updated version through 2001 is available online here:
   The author should also reference more recent work:
   [1]http://www.cru.uea.ac.uk/cru/data/temperature/
   Jones, P.D., M. New, D.E. Parker, S. Martin, and J.G. Rigor, Surface Air Temperature and
   its Changes over the Past 150 Years, Reviews of Geophysics, 37 (2), 173-199, 1999.
   see also the additional references and information in the website indicated above.
   3) It seems to me that a number of other papers on long-range dependence in surface
   temperature series have been published over the past 5 years (e.g. Smith, Nychka, others),
   and the author needs to do a far more thorough literature review. The reviewers literature
   review looks, on the average, to be about 5 years or so out of date...
   I would thus suggest that the authors resubmit the paper for consideration after
   appropriately dealing with the issues outlined above.
   _______________________________________________________________________
   the short /late response
   -------------------------------------------------------------------------------------------
   -----------
   I have finally read this paper and since you are so anxious to get a quick answer my
   opinion is that it is not the type of paper that paleo people would understand or be much
   interested in. This sort of thing has been looked at before and I do not think there is
   much to justify publishing it here. It would be better sent to a stats journal or climate
   journal that publishes statistical analysis of climate series . I think journal of climate
   would be a good option.
   I do not see anything glaringly wrong but I would suggest it is not your kind of thing.
   -------------------------------------------------------------------------------------------
   -------------
   At 04:29 PM 9/24/03 +0000, you wrote:

     Dear Prof. Briffa,
     I am writing you in connection with a paper submitted to The Holocene
     Research Papers a long time ago and titled: "A global warming in the
     temperatures in the Northern hemisphere using fractionally integrated
     techniques".
     On 02 May 2003 you replied to me saying that you were still waiting for
     the comments of the second referee.
     I would be very glad if you can inform me about the progress of the paper.
     Sincerely
     Dr. Luis A. Gil-Alana
     On Fri, 02 May 2003 10:13:02 +0100 Keith Briffa wrote:
     > Dear Dr Gil-Alana
     > this is a brief note to say that I am still chasing up the second referee
     > regarding your paper. I am away for a week now and hope to get some
     > response by the time I return. Sorry about the delay but I will try
     > to get
     > a reply to you soon. Keith
     >
     > --
     > Professor Keith Briffa,
     > Climatic Research Unit
     > University of East Anglia
     > Norwich, NR4 7TJ, U.K.
     >
     > Phone: +44-1603-593909
     > Fax: +44-1603-507784
     >
     > [2]http://www.cru.uea.ac.uk/cru/people/briffa/
     Este mensaje ha sido enviado con Buzn - [3]www.unav.es

   --
   Professor Keith Briffa,
   Climatic Research Unit
   University of East Anglia
   Norwich, NR4 7TJ, U.K.

   Phone: +44-1603-593909
   Fax: +44-1603-507784
   [4]http://www.cru.uea.ac.uk/cru/people/briffa[5]/

