Meteorological Simulations in the Cloud with the ASKALON Environment Gabriela Andreea Morar 1 , Felix Schüller 2 , Simon Ostermann 3 , Radu Prodan 3 , and Georg Mayr 2 1 Babes-Bolyai University, Cluj-Napoca, Romania gabriela.morar@econ.ubbcluj.ro 2 Institute for Meteorology and Geophysics, University of Innsbruck {felix.schueller,georg.mayr}@uibk.ac.at 3 Institute of Computer Science, University of Innsbruck {simon,radu}@dps.uibk.ac.at Abstract. Precipitation in mountainous regions is an essential process in meteorological research for its strong impact on the hydrological cycle. To support scientists, we present the design of a meteorological applica- tion using the ASKALON environment comprising graphical workﬂow modeling and execution in a Cloud computing environment. We illus- trate performance results that demonstrate that, although limited by Amdahl’s law, our workﬂow can gain important speedup when executed in a virtualized Cloud environment with important operational cost re- ductions. Results from the meteorological research show the usefulness of our model for determining precipitation distribution in the case of two ﬁeld campaigns over Norway. 1 Introduction Scientiﬁc computing requires an ever-increasing number of resources to deliver results for growing problem sizes in a reasonable time frame. Today, Cloud com- puting provides an alternative by which parallel resources are no longer hosted by the researcher’s computational facilities or shared as in computational Grids, but leased from large specialized data centers only when needed. To account for the heterogeneity and loosely coupled nature of resources, the scientiﬁc com- munity adopted the workﬂow paradigm based on loosely coupled coordination of atomic activities as one of the most successful programming paradigms. As a consequence, numerous eﬀorts among which the ASKALON environment [1] developed integrated environments to support the development and execution cycle of scientiﬁc workﬂows on dynamic Grid and Cloud environments. In this paper, we illustrate a case study of using ASKALON for porting and executing a meteorological application in a real Cloud environment. First of all, the applica- tion is speciﬁed by the user at a high-level of abstraction using a graphical UML modeling tool or an XML-based speciﬁcation language. A set of advanced mid- dleware services consisting of resource management, scheduling, and enactment I. Caragiannis et al. (Eds.): Euro-Par 2012 Workshops, LNCS 7640, pp. 68–78, 2013. c  Springer-Verlag Berlin Heidelberg 2013