date: Mon, 30 Jan 2006 10:32:38 +0000 from: Tim Osborn subject: Re: erik sea level to: Julie Jones ,Eduardo.Zorita@gkss.de, fidelgr@fis.ucm.es,schnur@dkrz.de,Keith Briffa 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 >************************************ > Attachment Converted: "c:\eudora\attach\magerik_f4.gif" 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