Ž . Parallel Computing 24 1998 911–922 Parallelization and performance of a meteorological limited area model M. Marrocu a , R. Scardovelli a,b, ) , P. Malguzzi c a CRS4, Õia N. Sauro 10, 09123 Cagliari, Italy b DIENCA, Õia dei Colli 16, 40136 Bologna, Italy c CNR-FISBAT, Õia Gobetti 101, 40129 Bologna, Italy Received 30 March 1996; revised 18 April 1997 Abstract We have developed a parallel implementation of a meteorological limited area model using a standard domain decomposition technique. Several communication strategies and message-passing libraries are compared. Results are presented for low, medium and high spatial resolutions. A good performance is obtained in the high resolution test case with an efficiency higher than 85% of the theoretical maximum. q 1998 Published by Elsevier Science B.V. All rights reserved. Ž . Keywords: Meteorological Limited Area Model LAM ; Message-passing libraries and interfaces: PVM; Chameleon; BlockComm; EUI-MPL 1. Introduction wx In this study, we consider the BOLAM system 1 , a research-oriented Limited Area Ž . Model LAM to study weather events in a complex environment. It is divided in three parts: initialization routines, meteorological model, and post processing routines. Here, the focus is on the meteorological model, the most complex and computationally expensive module. Typical spatial resolutions of state-of-the-art LAMs are in the order of a few tens of kilometers. However, there is a strong interest in the investigation of their performance, in particular the dynamics, radiation and convection parameterizations, near the limit of validity of the hydrostatic approximation at about 7–10 km. For these reasons, we have ) Corresponding author. E-mail: raus@crs4.it 0167-8191r98r$19.00 q 1998 Published by Elsevier Science B.V. All rights reserved. Ž . PII: S0167-8191 98 00032-5