date: Fri Jul 12 12:43:29 2002
from: Keith Briffa <k.briffa@uea.ac.uk>
subject: Fwd: Re: Reconstructions
to: drdendro@ldeo.columbia.edu
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From: Ricardo Villalba <ricardo@lab.cricyt.edu.ar>
To: Keith Briffa <k.briffa@uea.ac.uk>
Subject: Re: Reconstructions
Date: Tue, 9 Mar 1999 10:56:05 -0300
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Dear Keith,
Attached to this message is the file
alerce.doc (Word97), which contains a plot of the Fitzroya chronologies from
Lara et al. (in press). I have included the smoothed version of the
chronologies, which shows better the low-frequency component. If you decide
to include it, I can send you the raw data to plot the chronologies
according to PAGES requirements. What software do you use for doing plots?
Do you have the possibility of working with Sigma Plot figures?
>Do you still think Inverse temperature in previous year?
We have tested the relationships between tree growth and climate for most
chronologies and we found that the inverse relationships with previous
summer tenperature is the dominant pattern. However, as we mention in the
summary for the INQUA meeting, which I sent you, we believe that CO2? is
weaking the relationshipsduring the most recent time. We have recently
compiled good precip. and temp. record from Valdivia for the period
1853-1883. These records were produced by a neat German guy, who lived in
Valdivia at that time. Chronologies are better correlated with this records
(0.6 to 0.75) than any other most recent record in the region. This let us
to think that something is changing the ecology of Fitzroya (Something
similar to your findings in Europe?). Anyway, the relationships with this
old record still support the inverse relationships between tree growth and
previous summer temperature.
>The fact that there are clear differences in the two temperature
>reconstructions (yours and the Lara et al) still make me think that the
>interpretation is difficult.
I agree with you that there are differences between both reconstructions.
However, this records are significantly correlated between them.
Differences are more marked in the low frequency components: the LIA is
present in Alerce, but is not clear in Lenca and so on. As you know, both
chronologies were standarized in different ways. Another reason is that
Fitzroya, as most trees growing in close canopy forest, are very sensitive
to dynamics of the forest. Disturbance, and gap dynamics introduce
important changes in the low-frequency variations of Fitzroya. We certainly
are conscious of that, and this was the main reason that led us to developed
a regional network of chronologies.
>I want to say that the potential for further
>long series is high but I feel I need to say something direct about the
>lack of clear common signal in the different Fitzroya series.
We mentioned that in our chapter for the Jones, Bradley and Jouzel Book.
Indeed, in that chapter we produced a records from the 8 millenium
chronologies available at that time. All the chronologies were standarized
using similar-conservative methods and the regional record, as expected,
show similarities but also differences with the previous two
reconstructions. Correlations between this regional record and climate,
still support the inverse relationship to previous summer temperature (Fig.
7).
>I also want to say something about long-timescale change being not
appparent in these
>data. In the London meeting , I showed a curve of the two reconstructions
>averaged. What do you think if I wished to put this in the paper and say
>the standardisation method(s) removed potential for seeing more than
>decadal-multidecadal changes?
Certainly, this is one possibility. The other is to include the regional
record that we present in Jones,Bradley, Jouzel, and a third possibility is
to show the new reconstruction based on 16 chronologies. Although this is a
preliminary reconstruction, is the one based on the large number of Fitzroya
chronologies. My feelings is that both the Rio Alerce and Lenca
reconstructions were the first attemps to show the potential of Fitzroya to
provide millenial chronologies. we have recongnized the limitations of these
reconstructions and now we are in ther porcess of improving this early
attempts. It will be interesting to see what Antonio think about that!!
There are new work going on and I would put more emphasize on the new
results and not just in the comparison of Alerce and Lenca.
>Also , this David Keys keeps hassling me about 536 and the 540s in general.
The hassle has also arrived to Mendoza. David has been calling us
insistently during the past few days. Pepe and I were talking to him for
about 2 hours last Friday. After that I definetly quit. Pepe is more pacient
and sitill is trying to get something reasonable from all this talks. After
interchanging some faxes and calls along this week, I saw that Pepe was
still talking with him yesterday. It looks like Pepe is going into David
personal affairs. Pepe told me that David is married with a Brazilian and
other stuffs. Hard to beleive! It looks like David does not care too much
about telephone bills.
Keith, please let me know if you need some additional information. I will
be pleased to sent it to you. Best regards,
Ricardo Villalba
Departamento de Dendrocronologma e Historia Ambiental
IANIGLA - CRICYT
C.C. 330, (5500) Mendoza, Argentina
Phone: 54-261-428-7029 ext. 33
Fax: 54-261-428-7370
e-mail: ricardo@lab.cricyt.edu.ar
--
Professor Keith Briffa,
Climatic Research Unit
University of East Anglia
Norwich, NR4 7TJ, U.K.
Phone: +44-1603-593909
Fax: +44-1603-507784
[1]http://www.cru.uea.ac.uk/cru/people/briffa[2]/