cc: tcrowley@ocean.tamu.edu
date: Tue, 1 Aug 2000 10:52:26 -0500
from: tom crowley <tom@ocean.tamu.edu>
subject: Briffa et al review JGRd2000R306
to: jgr@gaia.envsci.Rutgers.EDU

Dear Roni,

Below is my review of Briffa et al. (JGRd 2000R306).  This is a very nice
paper.  The new analysis makes a good case that summer temperatures were
colder than previously estimated - this is an important conclusion that is
relevant both to the magnitude of climate change and mechanisms required to
explain the changes.

I recommend publication with only very minor changes, which I do not need
to see.

Tom Crowley


Review of Briffa et al. (JGRd2000R306)

I really liked this paper.  It is a careful reanalysis of a large number of
tree ring data that makes a good case for summer temperatures being colder
in most regions than previously estimated.  I recommend that the paper be
published with only minor changes, which I do not need to see.

Comments:

- p. 6, second full para., line 9, I may have missed it but there seems to
be no callout for Figure 5 - the text just says "This figure..."  With
respect to Fig 5 it would be helpful for those interested in gritty details
to put larger tick marks at the mid-century points so that the reader can
more easily narrow down the ages of certain events

- p. 7, even though the authors restrict their summation to NH land summer
half-season, it would be useful if they listed the correlation between this
index and NH mean annual temperatures.  In an earlier study Crowley and Kim
(GRL, 3:359-362, 1996, Fig. 2 and text) obtained a 0.8 correlation for the
interval ~1890-1990.  How would the correlation change for the interval
discussed by the authors?

- p. 10, bottom, it would be nice if the authors expanded a little on
possible circulation patterns that could account for the Siberian warming -
AO?  Their time series data are intriguing - in addition to the obvious
ENSO peaks there is some indication from Pacific coral data for 14 AND 17
year peaks - not in the same corals but in different sites.  This result
has long puzzled me - maybe there are really two oscillations with
different periods in different regions.  The significance of these
oscillations probably still needs testing.  This is more of a comment for
the authors rather than any recommendation to expand on the point.

END OF REVIEW




Thomas J.  Crowley
Dept. of Oceanography
Texas A&M University
College Station, TX  77843-3146
409-845-0795
409-847-8879 (fax)
409-845-6331 (alternate fax)


