date: Mon, 30 Jan 2006 10:32:38 +0000
from: Tim Osborn <t.osborn@uea.ac.uk>
subject: Re: erik sea level
to: Julie Jones <Julie.Jones@gkss.de>,Eduardo.Zorita@gkss.de, fidelgr@fis.ucm.es,schnur@dkrz.de,Keith Briffa <k.briffa@uea.ac.uk>

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It is clearly very difficult to separate the signal of response to 
forcings (that we want) from the long-term drift (that we don't want) 
by selecting layers in this way.

It looks like there is a response to the 20th century anthropogenic 
greenhouse forcing at all depths down to 600m (and maybe below).  And 
the drift-related trends are evident (I think) up to at least 250m 
(and maybe above).  Clearly tricky.

If it's easy, then I guess it would be nice to see the curve obtained 
just from the upper ocean (say above 425m like you suggest) and 
compare this with the full-depth results already obtained (don't 
throw this away!).

But, as mentioned before, I think the constant salinity calculation 
is the more important.  Yes, it will still have a drift component, 
but perhaps not so large?  I wonder whether we could use the MAGICC 
emulation to estimate the temperature drift component - it reproduced 
the ECHO-G heat flux into the ocean reasonably well (see bottom panel 
of attached graph).

Or perhaps we just ignore sea level in erik as being impossible to 
diagnose without a control run to estimate the adjustment/drift 
term.  erik2 will presumably have less sea level drift (though still 
some I guess) which may be useful for future work, but no time for 
using that within the SO&P project.

Any other suggestions?

Cheers

Tim

At 09:21 30/01/2006, Julie Jones wrote:

>Dear Tim, Edu, Fidel,
>
>Do you have a suggestion as to the depths to inlude in a sea level
>calculation just using the upper layers.  I've attached Fidel's plot of
>temperatures at the different levels, and here it appears that there's
>already a trend at 600m.  Does it make sense to calculate the sea level
>from surface to 425m depth?
>
>cheers
>
>Julie
>
>************************************
>Dr. Julie M. Jones
>Institute for Coastal Research
>GKSS Forschungszentrum
>Max-Planck-Strasse
>D-21502 Geesthacht
>Germany
>
>e-mail: jones@gkss.de
>phone: +49 (0)4152 871845
>fax: +49 (0)4152 871888
>************************************
>

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Attachment Converted: "c:\eudora\attach\magerik_f4.gif"
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Dr Timothy J Osborn
Climatic Research Unit
School of Environmental Sciences, University of East Anglia
Norwich  NR4 7TJ, UK

e-mail:   t.osborn@uea.ac.uk
phone:    +44 1603 592089
fax:      +44 1603 507784
web:      http://www.cru.uea.ac.uk/~timo/
sunclock: http://www.cru.uea.ac.uk/~timo/sunclock.htm
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