cc: lbutler@ucar.edu, k.briffa@uea.ac.uk
date: Wed, 2 Jun 1999 11:19:35 -0600 (MDT)
from: Tom Wigley <wigley@meeker.ucar.edu>
subject: Re: Paleo and Balling
to: Phil Jones <p.jones@uea.ac.uk>

Thanks, Phil.  I've faxed a copy to Tom in Copenhagen.  

Lisa

On Tue, 1 Jun 1999, Phil Jones wrote:

> 
>  Lisa,
>     Tom requires this for a public debate he's having with
>  Michaels and other skeptics on June 7. He tells me he's in
>  Denmark at the moment. I couldn't get something to him yesterday
>  as it was a holiday here. Can you forward the reply to him ?
> 
>  Cheers
>  Phil
> 
>  Tom,
>    Keith's in the Ural mountains for the next two weeks. You
>  probably emailed Malcolm re this one Utah chronology. As you say
>  this is one chronology, but Balling shouldn't have reconstructed
>  ANNUAL temperature. This may only work as the growing season is
>  part of the year. Malcolm may know if this is a good site for
>  temperature, also what standardization, if any, was used. Balling
>  doesn't say what r-squared he got or anything about Calib/Verif
>  or why the tree width series was deautocorrelated. So I would
>  say single site is the main point to make and his detail-less
>  calibration. Balling wouldn't accept a global/hemipsheric
>  temperature series based on one station - so why accept one
>  based on on tree series. He quotes an r value of 0.45, which is
>  not very high !
> 
>    Looking at Balling's figure (#1) it would seem from the skew
>  of his reconstructions that he has an inverse relationship
>  with temperature (ie it's really precip that the trees respond
>  to). I would expect 'real' annual temps in Utah to be -vely
>  skewed. Ring widths will be -vely skewed. He has +ve skew in the
>  reconstruction, hence the presumed inverse relationship. Despite
>  his small r value of 0.45, he has quite a range in the 
>  reconstruction. I would doubt whether Utah could get 4C warmer
>  in a year.
> 
>     If you use many more proxy series ( tree rings/ widths, ice
>  cores, historical etc) then you get a different view of the 
>  past 1000 years. The papers to mention are 
> 
>  a) Jones et al (1998) in The Holocene 8 467-483.
> 
>  b) Mann et al (1998) Nature 392 779-787 and GRL(1999) 26, 759-762.
> 
>  c) Briffa et al (1999) Science compass piece in early May.
> 
>  All 3 use different sets of paleo series ( Jones 17 long series,
>  Mann about 100 and Keith about 400 density series).
> 
>  All conclude that 20th century is the warmest of the millennium
>  and the warming during it unprecedented since 1400. All
>  centuries this millennium are cooler than the 1961-90 base
>  period - the 20th by about -0.05 and the 17th (coldest) 0.5
>  below 1961-90. Warmest century in the first half of the
>  millennium was about 0.1-0.2 below 1961-90. Range of values
>  of decades over the last 1000 years is quite small - 1990s
>  about 0.35 and 1601-1610 -0.7. Even the coldest year of 1601
>  was only about 1 C below 1961-90.  This level of variability of
>  hemipsheric average temperature is in accord with the long
>  model control runs and the few runs with solar forcing since
>  ~ 1650.
> 
>  Hope this is of some use.
> 
>  Cheers
>  Phil
> 
> 
> Prof. Phil Jones
> Climatic Research Unit        Telephone +44 (0) 1603 592090 
> School of Environmental Sciences    Fax +44 (0) 1603 507784 
> University of East Anglia                      
> Norwich                          Email    p.jones@uea.ac.uk 
> NR4 7TJ
> UK
> 
> ----------------------------------------------------------------------------
> 
>     
> 


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       *Tom M.L. Wigley						*
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