Operational Numerical Weather Prediction systems based on Linux cluster architectures

The progress in weather forecast and atmospheric science has been always closely linked to the improvement of computing technology. In order to have more accurate weather forecasts and climate predictions, more powerful computing resources are needed, in addition to more complex and better-performing numerical models. To overcome such a large computing request, powerful workstations or massive parallel systems have been used. In the last few years, parallel architectures, based on the Linux operating system, have been introduced and became popular, representing real“high performance–low cost” systems. In this work the Linux cluster experience achieved at the Laboratory for Meteorology and Environmental Analysis (LaMMA-CNR-IBIMET) is described and tips and performances analysed

High-performance computing enables simulations to transform education

This paper presents the case that education in the 21st Century can only measure up to national needs if technologies developed in the simulation community, further enhanced by the power of high performance computing, are harnessed to supplant traditional didactic instruction. The authors cite their professional experiences in simulation, high performance computing and pedagogical studies to support their thesis that this implementation is not only required, it is feasible, supportable and affordable. Surveying and reporting on work in computer-aided education, this paper will discuss the pedagogical imperatives for group learning, risk management and “hero teacher” surrogates, all being optimally delivered with entity level simulations of varying types. Further, experience and research is adduced to support the thesis that effective implementation of this level of simulation is enabled only by, and is largely dependent upon, high performance computing, especially by the ready utility and acceptable costs of Linux clusters

Simulations of Ground Motion in the Los Angeles Basin Based upon the Spectral-Element Method

We use the spectral-element method to simulate ground motion generated by two recent and well-recorded small earthquakes in the Los Angeles basin. Simulations are performed using a new sedimentary basin model that is constrained by hundreds of petroleum-industry well logs and more than 20,000 km of seismic reflection profiles. The numerical simulations account for 3D variations of seismic-wave speeds and density, topography and bathymetry, and attenuation. Simulations for the 9 September 2001 M_w 4.2 Hollywood earthquake and the 3 September 2002 M_w 4.2 Yorba Linda earthquake demonstrate that the combination of a detailed sedimentary basin model and an accurate numerical technique facilitates the simulation of ground motion at periods of 2 sec and longer inside the basin model and 6 sec and longer in the regional model. Peak ground displacement, velocity, and acceleration maps illustrate that significant amplification occurs in the basin

High-performance computing enables simulations to transform education

This paper presents the case that education in the 21st Century can only measure up to national needs if technologies developed in the simulation community, further enhanced by the power of high performance computing, are harnessed to supplant traditional didactic instruction. The authors cite their professional experiences in simulation, high performance computing and pedagogical studies to support their thesis that this implementation is not only required, it is feasible, supportable and affordable. Surveying and reporting on work in computer-aided education, this paper will discuss the pedagogical imperatives for group learning, risk management and “hero teacher” surrogates, all being optimally delivered with entity level simulations of varying types. Further, experience and research is adduced to support the thesis that effective implementation of this level of simulation is enabled only by, and is largely dependent upon, high performance computing, especially by the ready utility and acceptable costs of Linux clusters

Spectral-Element and Adjoint Methods in Seismology

We provide an introduction to the use of the spectral-element method (SEM) in seismology. Following a brief review of the basic equations that govern seismic wave propagation, we discuss in some detail how these equations may be solved numerically based upon the SEM to address the forward problem in seismology. Examples of synthetic seismograms calculated based upon the SEM are compared to data recorded by the Global Seismographic Network. Finally, we discuss the challenge of using the remaining differences between the data and the synthetic seismograms to constrain better Earth models and source descriptions. This leads naturally to adjoint methods, which provide a practical approach to this formidable computational challenge and enables seismologists to tackle the inverse problem

Software framework for geophysical data processing, visualization and code development

IGeoS is an integrated open-source software framework for geophysical data processing under development at the UofS seismology group. Unlike other systems, this processing monitor supports structured multicomponent seismic data streams, multidimensional data traces, and employs a unique backpropagation execution logic. This results in an unusual flexibility of processing, allowing the system to handle nearly any geophysical data. In this project, a modern and feature-rich Graphical User Interface (GUI) was developed for the system, allowing editing and submission of processing flows and interaction with running jobs. Multiple jobs can be executed in a distributed multi-processor networks and controlled from the same GUI. Jobs, in their turn, can also be parallelized to take advantage of parallel processing environments such as local area networks and Beowulf clusters. A 3D/2D interactive display server was created and integrated with the IGeoS geophysical data processing framework. With introduction of this major component, the IGeoS system becomes conceptually complete and potentially bridges the gap between the traditional processing and interpretation software. Finally, in a specialized application, network acquisition and relay components were written allowing IGeoS to be used for real-time applications. The completion of this functionality makes the processing and display capabilities of IGeoS available to multiple streams of seismic data from potentially remote sites. Seismic data can be acquired, transferred to the central server, processed, archived, and events picked and placed in database completely automatically