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SUMMARY:An Inter-Comparison of Icosahedral Climate Models on the G8 Call: 
 ICOMEX Project - Ryuji Yoshida\,   (RIKEN/AICS)
DTSTART:20120928T125500Z
DTEND:20120928T132000Z
UID:TALK40244@talks.cam.ac.uk
CONTACT:Mustapha Amrani
DESCRIPTION:The ICOsahedral-grid Models for EXascale Earth system simulati
 ons (ICOMEX) is the consortium for the climate models development toward t
 he exascale computing. It started since October 2011 as one of the G8 call
  projects. Participated are NICAM (Japan)\, ICON (Germany)\, MPAS (UK and 
 US)\, and DYNAMICO (France) model teams. On the road to the exascale compu
 ting\, we would find many road blocks\, such as file I/O speed\, lower byt
 e/flops rate\, outer/inner node communication. In order to examine these p
 roblems\, six working groups are seated together. The Japan team works on 
 the model inter-comparison to be synergistic among working groups. Althoug
 h all the participated models use the icosahedral-grid\, the discretizatio
 n methods are different. For example\, the hexagonal shape of a control vo
 lume is used in NICAM\, while the triangular shape is used in ICON. Throug
 h intercomparison of both computational and physical performances between 
 models\, we will find which aspects of the model configuration are advanta
 gous toward exascale computing. Two types of experiments were performed un
 til now using NICAM and ICON: the baroclinic wave test (Jablonowski and Wi
 lliamson\, 2006) and the statistical climatology test (Held and Suarez\, 1
 994). The horizontal resolution is from 240km (glevel-5) to 14km (glevel-9
 )\, and higher resolution runs will be tested in future. For the Held and 
 Suarez test case\, NICAM and ICON simulated climatology similar to that sh
 own in the original paper. The baroclinic wave test is also compared betwe
 en the two models. To investigate computational aspects\, we examined stro
 ng scaling of parallel computing. Tests were performed on the Westmere and
  Bulldozer machine by using 5 through 40 MPI processes. We found that the 
 two models have a good scaling: the measured scaling efficiency is 0.8-0.9
 . We plan to perform the intercomparison experiments using K computer usin
 g a larger number of processes O(10^5) to examine detail profiles of very 
 massive parallel cores.\n\n
LOCATION:Seminar Room 1\, Newton Institute
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