Application of OpenMP to Weather, Wave and Ocean Codes

Weather forecast limited area models, wave models and ocean models run commonly on vector machines or on MPP systems. Recently shared memory multiprocessor systems with ccNUMA architecture (SMP-ccNUMA) have been shown to deliver very good performances on many applications. It is important to know that the SMP-ccNUMA systems perform and scale well even for the above mentioned models and that a relatively simple effort is needed to parallelize the codes on these systems due to the availability of OpenMP as standard shared memory paradigm. This paper will deal with the implementation on a SGI Origin 2000 of a weather forecast model (LAMBO — Limited Area Model Bologna, the NCEP ETA model adapted to the Italian territory), a wave model (WA.M. — Wave Model, on the Mediterranean Sea and on the Adriatic Sea) and an ocean model (M.O.M. — Modular Ocean Model, used with data assimilation). These three models were written for vector machines, so the paper will describe the technique used to port a vector code to a SMP-ccNUMA architecture. Another aspect covered by this paper are the performances that these models have on these systems