Advancing X-cutting Ideas for Computational Climate Science

New dates for AXICCS: Sept 12-13, 2016.

Plenary Speakers

Christopher S. Bretherton

Frontiers in multiscale and global simulation of boundary layer clouds and their interactions with climate

The representation in global climate models of clouds and aerosols, particularly in marine atmospheric boundary layers, has been a major source of uncertainty in constraining cloud feedbacks and anthropogenic aerosol effects on climate change. The uncertainty stems mainly from the need to parameterize several interacting cloud-controlling processes that vary hugely across the scale of a climate model grid cell. One can now envision large-domain large-eddy simulation (LES) of boundary layer clouds that encompass the full range from turbulence (~100 m) to near-global scales. This can sidestep parameterization uncertainties and improve our understanding of regional and global cloud-climate interaction. Strategic directions to achieve maximum science benefit using large-domain LES with finite computing resources are proposed.

Chris Bretherton is an atmospheric scientist who studies cloud formation and turbulence and improves how they are simulated in global climate and weather forecast models. His research includes participating in field experiments and observational analyses, three-dimensional modeling of fluid flow in and around fields of clouds, and understanding how clouds will respond to and feed back on climate change. Computer code developed by his research group for simulating cloud formation by atmospheric turbulence is used in the two leading US climate models. He was a lead author of the Intergovernmental Panel on Climate Change Fifth Assessment Report in 2013, Chair of a 2012 National Academy report entitled A National Strategy for Advancing Climate Modeling, and a former director of the University of Washington Program on Climate Change. In 2012, he received the Jule G. Charney Award, one of the two highest career awards of the American Meteorological Society. He is also a Fellow of the American Meteorological Society and American Geophysical Union.

William D. Collins

Climate Simulation at Impactful Scales: Charge for a New Physics Paradigm

The traditional formulations of the fast, sub-grid physics in climate simulations are rapidly reaching the limits of their validity. At the small scales needed for climate projection relevant to impacts assessments, many of the simplifying assumptions in these formulations are longer valid. These classical parameterizations should be replaced with demonstrably more accurate, convergent, and multiscale representations of the key climate processes. We demonstrate the need for new approaches using results from DOE's CASCADE and Multiscale projects investigating hydrometeorological extremes using telescopic climate models. We conclude by discussing the opportunities for engagement with the applied mathematical and computational science communities in developing a new class of exascale climate models with much more rigorous theoretical and empirical foundations.

William Collins is an internationally recognized expert in climate modeling and climate change science. His personal research concerns the interactions among greenhouse gases and aerosols, the coupled climate system, and global environmental change.

At Lawrence Berkeley National Laboratory (LBNL), Dr. Collins serves as the Director for the Climate and Ecological Sciences Division. At the University of California, Berkeley, he teaches in the Department of Earth and Planetary Science and directs the new multi-campus Climate Readiness Institute (CRI).

Dr. Collins's role in launching the Department of Energy's Accelerated Climate Model for Energy (ACME) program was awarded the U.S. Department of Energy Secretary's Achievement Award on May 7, 2015. He is also a Fellow of the American Association for the Advancement of Science (AAAS). He was a Lead Author on the Fourth Assessment of the Intergovernmental Panel on Climate Change (IPCC), for which the IPCC was awarded the 2007 Nobel Peace Prize, and was also a Lead Author on the recent Fifth Assessment.

Before joining Berkeley and Berkeley Lab, Dr. Collins was a senior scientist at the National Center for Atmospheric Research (NCAR) and served as Chair of the Scientific Steering Committee for the DOE/NSF Community Climate System Model project.

Dr. Collins received his undergraduate degree in physics from Princeton University and earned an M.S. and Ph.D. in astrophysics from the University of Chicago.

Petros Koumoutsakos

The Art of Computational Science: Closing Gaps, Forming Alloys

A Computer Scientist works with a Mechanical Engineer to uncover the secrets of fish schooling, a Chemist works with a Mathematician to quantify water transport in carbon nanotubes, a Civil Engineer works with a Naval Architect and a Medical Doctor to understand placental plasticity. These are examples from our work that I wish to discuss as paradigms of integrating disciplines through Computational science in order to solve challenging scientific problems. At the same time we are concerned with challenges of this field, such as the software-hardware gap and the integration of Computing with Data Sciences. I will discuss successes and failures and I hope to draw some conclusions and receive feedback that may be useful for solving problems across scientific domains.

Professor Koumoutsakos conducts research at the interface of Simulation and Data Sciences with emphasis fundamentals and applications in areas of Fluid Mechanics, Life Sciences and Nanotechnology.

Professor Koumoutsakos received his Diploma (1986, National Technical University of Athens, Greece) and Master's (1987, University of Michigan, Ann Arbor, USA) in Naval Architecture. He received a Master's (1988) and PhD in Aeronautics and Applied Mathematics (1993) from the California Institute of Technology (USA). He was an NSF fellow in parallel computing (1993-1994, Caltech Center for Research on Parallel Computation) and a research associate (1994-1997) with the Center for Turbulence Research at NASA Ames/Stanford University. He was an Assistant professor of Computational Fluid Dynamics (1997-2000) at ETH Zurich. He was named professor of Computational Science at ETH Zurich in 2000. He was the founding director of the ETH Zurich Computational Laboratory (2000-2007) and of the Zurich Graduate School in Computational Science (2014). He is presently a Fellow of the Collegium Helveticum and of the Radcliffe Institute at Harvard University (2016-2017).

Professor Koumoutsakos is an elected Fellow of the American Physical Society (APS), the American Society of Mechanical Engineers (ASME) and the Society or Industrial and Applied Mathematics (SIAM). His other awards include the 2013 Gordon Bell Award by the Association of Computing Machinery (ACM) and the Advanced Investigator Award by the European Research Council.

George Mozdzynski

Addressing future Scalability and Power challenges at the European Centre for Medium-Range Weather Forecasts (ECMWF)

ECMWF is pursuing a long term Programme on Scalability that aims at developing the next-generation forecasting system addressing the challenges of future exascale high-performance computing and data management architectures. The Programme is required to optimize system performance allowing ECMWF to fulfil its strategy within expected funding and environmental constraints. Key components of model, data assimilation, code adaptation to new and emerging hardware solutions as well as data pre- and post-processing are included. The Scalability Programme is expected to produce new capabilities at ECMWF, namely:

In this talk I will present an update on the ECMWF Scalability Programme, and recent developments and experiences on running high resolution forecast models on today's petascale supercomputers.

George Mozdzynski has extensive professional experience of different aspects of supercomputing. He received a Bsc (Hons) degree in Computer Science from Imperial College, London, in 1976. From 1976 to 1985, he worked for Control Data Corporation in the areas of pre-sales, post-sales and benchmarking, working on scalar (CDC CYBER series systems and vector systems (CYBER205). One of his early roles at CDC was as part of a team that wrote a CRAY station facility that provided job and file transfer capabilities between a CRAY1 and a CYBER 175 front-end, the first end-user being ECMWF (who he now works for). From 1986 to 1989 he worked at ETA Systems (ETA10) and from 1989-1994 for Kendall Square Research (KSR1, KSR2) with its innovative AllCache architecture, covering pre-sales and benchmarking activities. He joined ECMWF in 1994, and since then has worked as part of a team on many technical developments to ECMWF's IFS weather forecast model. This included the first distributed memory MPI implementation of IFS, the current hybrid MPI/OpenMP implementation, the EQ_REGIONS partitioning scheme and the radiation interface. From 2011 to 2014 he worked as part of the ECMWF team on the EU funded CRESTA project ( with specific interest in the use of PGAS techniques.