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SUMMARY:Reexamination of non-hydrostatic formulations using the hydrostati
 c-pressure based co-ordinates - Takeshi Enomoto\,   (Kyoto University)
DTSTART:20120926T082500Z
DTEND:20120926T085000Z
UID:TALK40139@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:The rapid increase of computing power is making global non-hyd
 rostatic simulations affordable. A natural approach is to extend the formu
 lation to include the non-hydrostatic effect. The advantage of this approa
 ch is that the existing data assimilation and tools require minimal change
 s. ECMWF and JMA seem to pursue this approach. ECMWF has achieved TL7999 (
 corresponding to approximately 2.5 km) with a fast Lendre transform using 
 the butterfly algorithm (Nils Wedi\, pers. comm.). Hiromasa Yoshimura (MRI
 /JMA) has built a non-hydrostatic version of JMA GSM using double Fourier 
 series. Their formulations are based on Laprise (1992) that proposes the v
 ertical co-ordinates based on hydrostatic pressure. Juang (1992\, 2000) al
 so adopts hydrostatic sigmaco-ordinates in the vertical but there are subt
 le differences. The latter introduces the hydrostatic temperature. In a li
 mited-area model\, such as MSM\, the hydrostatic temperature may be given 
 externally. In a GCM\, however\, the hyd rostatic temperature must be dete
 rmined internally if is not time-independent. We investigated the two form
 ations and found the assumption of the hydrostatic state of Laprise (1992)
  may be used to diagnose the hydrostatic temperature within MSM. Similarly
  the hydrostatic assumption of Arakawa and Konor (2009) can be used. MSM i
 s found to run stably with any of these diagnosed hydrostatic states. The 
 diagnosed hydrostatic temperature would enable the application of the form
 ulation of MSM to the global domain.\n\n
LOCATION:Seminar Room 1\, Newton Institute
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