date: Wed, 06 Nov 2002 14:25:58 -0700
from: "Dr. Jacek Majorowicz" <majorowiczatXYZxyzw.ca>
subject: Re:Majorowicz view
to: Tim Osborn <t.osbornatXYZxyz.ac.uk>
Thank you for your very interesting paper with Dr. Briffa.
HC 2001 GRL paper makes an assumption in which the observational (etheo
station's based) surface temperatures are part of their model.Their model
used to fit temperature anomalies with depth conssists of the observational
(metheorological stations) and pre-observational level which is the only
freedom level in the model.
Well temperature mathod can only show ground warming changes and this is
sometimes different from the air surface temperature changes. This is
especially the case when our well data come from the remote areas which
went through land changes (clear cutting, changing of grass land to
agriculture or grazing systems, forest fires etc plus changes in boundary
conditions like moisture, snow etc). Staraight comparison of these with
standard condition metheorological stations is therefore difficult or not
In fact some of the above conditions are likely the cause for ground surface
temperature warming magnitudes in the last century to be higher than air
surface temperature changes from metheorological stations.
In many of my papers we showed that GST warming from wells is higher than
SAT based warming from metheo stations . Therefore large warming change
showed by HO 2001 is maybe a result of the above i.e. well reconstructions
show higher groud surface warming than oservational air surface data in many
areas consisting their well data basis. (see our Skinner and Majorowicz,
Climate Research, v. 12, 39-52,1999 and my previous work in Clim. Change in
1977 (35, p. 485-500). Asuuming these as part of the ground surface
temperature change model is therefore risky.
I have attached very schematic figure (showed it in Nice at EGS 2002 at
Mann's at al session) in which I compare Huang Pollack Shen (2000, v. 403.
17 February) northern hemisphere reconstruction from wells with Mann and
Jones (lower) proxy reconstructions. Instead of using year 2000 as reference
(as Huang et al in their Nature work) I am shifting their curve (based on
well temperature reconstructions) to 1600hundreds level. Such relative
change of levels sugest that if let's say Jones et al., level before major
recent warming is correct, the well temperature reconstruction level is
higher in the recent couple centuries and mainly in 20th century. This in
fact is what I observe across Canada. My warming magnitudes for ground
warming are higher than metheo observation.
I realise that it is all relative where we put the level for comparison .,
howeer, it leads to different interpretations. One can say that proxy data
fail to show previous significant cooling before last century warming; I can
say that well temperature based ground warming is higher than observations
in recent years for the reasons as above.
I hope this insight will be of interest.
I am hoping to make it to EGS 2003 in Nice and hope to see you and have some
----- Original Message -----
From: "Tim Osborn" <t.osbornatXYZxyz.ac.uk>
To: "Dr. Jacek Majorowicz" <majorowiczatXYZxyzw.ca>
Sent: Tuesday, November 05, 2002 7:49 AM
Subject: Re: jgr reprint attached
> At 17:33 02/11/02, you wrote:
> >with best regards
> Thanks - looks very interesting. I attach one in return!
> Dr Timothy J Osborn | phone: +44 1603 592089
> Senior Research Associate | fax: +44 1603 507784
> Climatic Research Unit | e-mail: t.osbornatXYZxyz.ac.uk
> School of Environmental Sciences | web-site:
> University of East Anglia __________| http://www.cru.uea.ac.uk/~timo/
> Norwich NR4 7TJ | sunclock:
> UK | http://www.cru.uea.ac.uk/~timo/sunclock.htm
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