date: Tue, 07 Sep 1999 13:53:26 +0100 from: Tim Osborn subject: comments on NERC long-term support to: k.briffa@uea Nothing terribly wrong with it, but is it worth 400K? It will improve upon the simpler models (e.g. proposed Millesym, or Rahmstorf/PIK CLIMBER model, or Stocker's model), but will it be a big enough improvement? It will have some chance at simulating the key processes of mid-latitude depressions, NAO and ENSO, but may not do them well enough. The only reference to the intermediate GCM is old (1975). Some recent studies suggest that a higher resolution than T21 is needed in order to simulate a realistic/strong response of the atmosphere to mid and high latitude SST variations - will the T21 IGCM be too insensitive and therefore fail to correctly simulate changes in storms, storm tracks, NAO etc. during different periods of the proposed simulation? ENSO is also mentioned as important, yet most recent studies show the need for high ocean resolution in the tropical Pacific to get a very realistic simulation. Will a low-res MOM ocean perform well enough? They will suggest that there is no alternative, since the full A/OGCM+ice+land is too slow to run. Dr Timothy J Osborn | phone: +44 1603 592089 Senior Research Associate | fax: +44 1603 507784 Climatic Research Unit | e-mail: t.osborn@uea.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