NASA/GSFC - Global Modeling and Assimilation Office
2010 - Present
• Leads the model development in GEOS-5 as Principal Investigator for the “Acceleration of the NASA GEOS-5 GCM using Graphic Processing Unit (GPU) technology”
• Leads the development of the non-hydrostatic finite-volume atmospheric dynamical core on the cubed-sphere for the GEOS-5 atmospheric model
• Leads the global high-resolution model development in preparation for the next generation, non-hydrostatic cloud-resolving version of the GEOS AGCM, GEOS-6. This effort led to the GEOS-5 AGCM being one of only two global models worldwide to simulate global weather at a horizontal resolution of 3.5-km. These high-resolution simulations are continuously evaluated using satellite observations from MODIS, CloudSat, CALIPSO, TRMM and others to improve model development and enhance our understanding of physically resolvable local/regional weather phenomena.
• Leads the high-resolution global mesoscale simulations with GEOS-5 for observing system simulation experiments (OSSEs) to test proposed observing system designs and assimilation techniques regarding new instruments and they’re deployments, assessing instrument accuracy, and the impact of measurements on analysis quality
• Completed the first global “Nature Run” simulation for OSSE development at 10-km global horizontal resolution, permitting the use of OSSEs to evaluate improvements on regional weather phenomenon such as tropical predictability and global aerosol distribution including organic/black carbon, dust and sulfates.
• Principal Investigator on the joint NOAA proposal “Towards improving convection parameterization in next-generation climate models” to the MAPP Program of the NOAA Climate Program Office
• Leads monthly telecons to facilitate the collaboration among the Modeling Analysis and Prediction program awardees in the development and analysis of the GEOS-5 AGCM
• Evaluates global high-resolution model simulations with respect to high resolution satellite observations and climate connections between meso-scale simulations of extreme events (hurricanes) and climate
• Produces cutting-edge scientific visualizations raising public awareness of global climate and weather model development efforts, and the impact of regional weather/climate events on global scales
NASA/GSFC - Advanced Software Technology Group
2008 - 2010
• Managed the Advanced Software Technology Group (ASTG), a team of 15 contractor staﬀ to provide support to NASA’s High End Computing Program and NASA’s Modeling and Prediction Program. ASTG is responsible for level 2 support for the NASA Center for Computational Sciences (NCCS) as well as benchmarking efforts for NASA high performance computing applications and numerous modeling integration efforts.
• Ported and executed the GEOS atmospheric model on the cubed-sphere for non-hydrostatic weather/climate modeling at 14- to 3-km global resolutions on the Cray XT5 at Oak Ridge National Laboratory (a petascale high performance computing system with a peak performance of 1.6 petaFlops) and the large Linux cluster at NASA Goddard Space Flight Center
• Integrated the cubed-sphere non-hydrostatic finite-volume dynamical core in the NASA GEOS atmospheric model and data assimilation system and the NASA GISS modelE climate model.
• Prepared the latlon and cubed-sphere finite-volume, and GISS modelE BQ dynamical cores for participation in the National Center for Atmospheric Research (NCAR) Advanced Study Program Summer Colloquium (ASPC) on Numerical Techniques for Global Atmospheric Models. The ASPC consisted of 13 premier international modeling groups contributing dynamical cores and modeling mentors for selected graduate students from the atmospheric sciences and applied mathematics to get hands-on experience with the latest numerical methods for dynamical core components. The ASPC also provided a unique opportunity for inter-comparison of cutting edge dynamical cores via standardized baroclinic idealized tests.
• Presented invited and contributed talks to international and national conferences on atmospheric model development and software scalability
NASA/GSFC - Software Integration and Visualization Office
2004 - 2008
• Developed the quasi-uniform cubed-sphere grid implementation of the finite-volume dynamical core; this work extends the scalability of the current Lat-Lon implementation to petascale processor counts of 10s to 100s of thousands of processors providing a stepping stone toward global cloud resolving non-hydrostatic weather/climate modeling at 10km and finer resolution.
• Managed the fvGCM 0.5-degree daily numerical weather prediction runs. This included: twice daily data updates with the NCEP data assimilation system, iteration of the fvGCM to produce 10-day global weather forecasts, post-processing and analysis of results.
• Supported the fvGCM 0.25-degree daily numerical weather prediction and hurricane experiments on the NASA Advanced Supercomputing Division SGI Altix cluster ‘Columbia’. This work focused on producing ground-breaking scientific achievements in the realm of high-resolution global modeling, focused on hurricane prediction for all aspects of hurricane development (generation, strengthening, track and intensity forecasts).
• Managed the benchmarking efforts for earth science applications of interest to NASA and users at the NASA Center for Computational Sciences at GSFC. Targeted applications were ported and profiled for early evaluation of emerging computational platforms.
• Optimized the fvGCM for improved performance on the SGI Altix platform. Optimizations resulted in a 35-40% improvement in overall model performance.
• Enabled an MPI version of the offline CLM land model used within the fvGCM to allow efficient testing for science modifications at high resolution. Execution time improved from 88 seconds per model day in serial to 9 seconds per model day using 16 processors on the Compaq AlphaServer SC45 ‘Halem’.
• Lead the educational/public outreach efforts for the NASA fvGCM and earth science applications via informative scientific visualization and unique public relations opportunities.
• Presented numerous seminars/workshops on model development and high performance computing at national and international conferences.
Senior Software Engineer
Science Applications International Corporation - Data Assimilation Office / Global Modeling and Assimilation Office
2001 - 2004
• Implemented MPI-1, MPI-2, SHMEM and MLP communication paradigms within a portable fortran90 communication module for the NASA Finite Volume General Circulation Model (FVGCM).
• Used MPI-2 thread-safe one-sided communication strategy to improve the scalability and overall performance of the NASA fvGCM by 30% on the 512 processor SGI Origin 3000 system.
• Ported the NASA fvGCM to the IBM SP3, Compaq AlphaServerSC, Linux platforms, and served as the point of contact on porting/testing/benchmarking efforts of the FVGCM on the Cray SX6.
• Served as a liaison for the Data Assimilation Office in the Community Atmospheric Model (CAM) development activities with NCAR and the DOE; and facilitated the merge of the fvGCM communication module within the CAM.
• Used VAMPIR parallel visual debugging tool to identify load imbalances caused by the Community Land Model (CLM2) and the Community Climate Model (CCM3) physics within the NASA fvGCM; modified the data distribution within the CLM2 based on the results of this analysis.
• Completed several case studies with the 0.5-degree resolution fvGCM in weather forecast mode; these studies included hurricane forecasts for Atlantic hurricanes Lili, Isidore, and Isabel, winter storm prediction including the 2003 President's Day storm which produced 2+ feet of snow throughout the mid-Atlantic, homeland security applications of plume dispersion modeling, and 10-day forecast and analysis of the splitting of the southern hemisphere ozone hole in the fall of 2002.
• Contributed to the parallelism of the Goddard Institute for Space Studies (GISS) modelE general circulation model in coordination with the NASA Center for Computational Sciences (NCCS). Completed several preparatory steps for standard 1-D domain decomposition within the modelE code. Prepared a comprehensive study of I/O requirements and completed a parallel implementation of all required I/O within the GISS modelE
Solutech Inc., Billet Construction Mgmt. Inc. - Indianapolis, Indiana
2000 - 2001
• Developed reusable Component Object Model (COM) and Distributed COM (DCOM) components with Microsoft Visual Basic for various client applications including inter-office project management for generic business models and surgical materials tracking for hospital environments.
• Used Microsoft Project to manage office progress on various software development tasks.
• Used Microsoft Visual Basic and Java to develop custom software for job tacking including quote management, subcontractor selection, materials purchase, milestone completion and final billing.
• Integrated Quickbooks Pro and Microsoft Outlook 2000 to develop a complete business solution for subcontractor supervision, insurance management and final billing.
Post-Masters Research Fellow
Oak Ridge Associated Universities - Oak Ridge National Laboratory – Climate Dynamics Group
1998 - 2000
• Developed statistical canonical correlation analysis (CCA) tools to establish regional downscaling capabilities for the ORNL Regional Climate Modeling Project.
• Produced high-resolution regional climate predictions from seasonal to interdecadal timescales based on the statistical relationships among the prediction of global climate from the Parallel Climate Model (PCM) and the Community Climate Model (CCM3) and regional observations of temperature, precipitation and stream flow from the Vegetation/Ecosystem Modeling and Analysis Project (VEMAP) and the US Geological Survey (USGS).
• Developed scalable Fortran90 modules for spherical harmonic transforms and grid transformations suitable for parallel computation and climate model development.
• Participated in the early design stages of the Community Atmospheric Model (CAM).
• Studied conservation and stability properties of high order cartesian (HOC) methods for the shallow water equations on a sphere.
• Analyzed the impact of focused grids on global and regional climate prediction.
Graduate Research Assistant
Florida State University - Center for Ocean-Atmospheric Prediction Studies
1996 - 1998
• Implemented a variational blending of Florida State University tropical winds and National Centers for Environmental Prediction reanalysis wind data over the Pacific Ocean.
• Examined the relationship between tropical and extra-tropical winds on El Nino-Southern Oscillation time-scales; and identified linkages between the Aleutian Low and tropical trade winds.
Undergraduate Student Research
University of Maryland at College Park - Department of Meteorology
1995 - 1996
• Performed back trajectory analyses of atmospheric data in the Washington DC area to study the impacts of the large-scale circulation on high ozone events in the Washington DC metropolitan region.
• Analyzed and determined the source of air parcels which preceded high ozone events in the Mid-Atlantic.
M.S. - 08/1998 : Meteorology - Florida State University, Tallahassee, FL
B.S. - 05/1996 : Computer, Mathematical, and Physical Science – University of Maryland, College Park, MD
American Geophysical Union
2008 - Present
Chi Epsilon Pi, National Meteorological Honor Society
1996 - Present
- 2010 Achievement Award. For outstanding contributions in preparing high resolution simulations that were the highlight of NCCS media events.
- 2002 NASA DAO/SRT Outstanding Performance Award - For exceptional work in the implementation of MPI-2 and parallel MPI-2 I/O that led to substantial improvement in the computational performance of the finite-volume GCM.
- 2001 NASA DAO/SRT Group Achievement Award - For outstanding contributions to the highly successful parallelization of the finite-volume GCM.
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Putman, W. M. 2006. The Finite-Volume Dynamical Core on the Cubed-Sphere SC 2006 Poster Reception