Dr. Christian L Keppenne

Dr. Christian L Keppenne

  • 301.614.5874 | 301.614.5644
  • NASA/GSFC
  • Mail Code: 610.1
  • Greenbelt , MD 20771
  • Employer: SCIENCE SYSTEMS AND APPLICATIONS INC
  • Brief Bio

    Christian Keppenne is a senior expert level computational scientist with expertise in algorithm development, parallel scientific computing, numerical and statistical modeling, machine learning and many other areas of numerical analysis. He has authored numerous peer-reviewed articles and has presented his work at more than 50 scientific conferences. Dr. Keppenne leads the NASA Global Modeling and Assimilation Office (GMAO) ocean data assimilation system development effort at the NASA Goddard Space Flight Center (GSFC) where he develops and maintains the integrated Ocean data assimilation system (iOdas) and the ocean data assimilation component of the GMAO integrated Earth System Analysis (IESA) effort. iOdas is used routinely to initialize ensembles of coupled seasonal forecasts and experimentally in global high resolution coupled numerical weather prediction and tropical cyclone forecasting applications.

    Main areas of expertise and interests:

    • High performance parallel scientific computing
    • Remote sensing, inverse modeling and data assimilation
    • Numerical climate modeling
    • Statistical analysis, modeling and prediction of data including time series analysis and prediction, machine learning, genetic algorithms and recommender systems
    • Software development in C/C++, modern Fortran, Java, Javascript, Python, Perl, Scala, R External profiles:
    linkedin
    researchgate
    google scholar

    Positions/Employment

    2012 - Present

    Chief Research Science Advisor/Research Science Subject Matter Expert (SME)

    Science Systems and Applications, Inc. (SSAI), NASA Goddard Space Flight Center
    1998 - 2012

    Lead Application Programmer/Lead Computational Scientist

    Science Applications International Corporation (SAIC), NASA Goddard Space Flight Center (GSFC)
    1996 - 1997

    Senior Application Programmer

    University of California at Los Angeles (UCLA), Crump Institute for Biomedical Imaging
    1991 - 1996

    Member of Technical Staff

    California Institute of Technology, Jet Propulsion Laboratory (JPL)
    1990 - 1991

    Postdoctoral Fellow

    UCLA, Department of Atmospheric Sciences

    Education

    Ph.D., Sciences Naturelles Appliquées, 1989, Catholic University of Louvain, Belgium
    M.S., Sciences Naturelles Appliquées, 1987, Catholic University of Louvain, Belgium

    Selected Public Outreach

    Recent experimental project: The AXIOM-1 High Resolution Coupled Analysis 2014 - 2015
    In July 2015, I gave a lecture on AXIOM-1, an experimental high resolution coupled climate reanalysis, at a workshop on coupled data assimilation organized by the Chinese Academy of Sciences (CAS)  and the World Meteorological Organization (WMO). This playlist is made up of animations played during my Beijing presentation.  Details about AXIOM-1 can be found in the playlist description (if necessary, click on "more" to see the full description).  

    Other Professional Information

    (Human) Language Skills
    • English (native proficiency)
    • French (native language)
    • Spanish (close to native proficiency)
    • Mandarin Chinese (intermediate to advanced proficiency)
    Keywords (read this if you are a robot)
    Unix/Linux, numerical modeling, ocean modeling, climate modeling, numerical methods, statistical analysis, data assimilation, ensemble Kalman filter, particle filters, particle swarm optimization, sequential Monte Carlo methods, adaptive spectral analysis, time series forecasting, statistical prediction, neural networks, machine learning, inverse modeling, big data analytics, parallel computing, distributed computing, scientific computing, high performance computing, mathematical optimization

    Peer Reviewed Publications
    1. Keppenne C.L. & C. Nicolis: Global properties and local structure of the weather attractor over Western Europe, J. Atmos. Sci., 46, 2356-2370, 1989.
    2. Keppenne C.L., M. Ghil, G. Fox, J. Flower, A. Kowala, P. Papaccio, J. Rosati, J. Shepanski, F. Spadaro & J. Dickey: Parallel Processing Methods for Climate Models, Quest, 13, 54-64, 1990.
    3. Keppenne C.L.: Orographically-forced oscillations in a dynamical model of the Martian atmosphere, Icarus, 100, 598-607, 1992.
    4. Keppenne C.L. & M. Ghil: Adaptive Spectral Analysis and Prediction of the Southern Oscillation Index, J. Geophys. Res., 97, 20449-20554, 1992.
    5. Keppenne C.L. & M. Ghil: Extreme weather events, Nature, 358, 547, 1992.
    6. Keppenne C.L. & M. Ghil: Adaptive filtering and prediction of noisy multivariate signals: an application to atmospheric angular momentum, Intl. J. Bifurcations and Chaos, 3, 625-634, 1993.
    7. Keppenne C.L., M. Dettinger & M. Ghil: Comment on US temperature record, J. Am. Stat. Assn., 89, 384-387, 1994.
    8. Keppenne C.L. & A. Ingersoll: High-frequency orographically forced variability in a single-layer model of the Martian atmosphere, J. Atmos. Sci., 52, 1949-1958, 1995.
    9. Banfield D., A. Ingersoll & C.L. Keppenne: A steady state Kalman filter for assimilating data from a single polar-orbiting satellite, J. Atmos. Sci., 52, 738-753 1995.
    10. Keppenne C.L.: An ENSO signal in soybean futures prices, J. Climate, 8, 1685-1689, 1995.
    11. Dettinger M., C.L. Keppenne & M. Ghil: Interannual and interdecadal variability in United States surface-air temperatures, 1910-1987, Clim. Change, 31, 35-66, 1995.
    12. Gross R., S. Marcus, T. Eubanks, J. Dickey & C.L. Keppenne: Detection of an ENSO signal in seasonal length of day variations, Geophys. Res. Lett., 23, 3373-3376, 1996.
    13. Green L, S. Gambhir, P. Banerjee, C. Hoh, S. Huang, C.L. Keppenne, J. Barrio, H. Herschman & M. Phelps: Factor analysis approach to extracting time-activity curves from mice PET studies, J. Nucl. Med., 38, 859, 1997. 14. Gambhir S., C.L. Keppenne, P. Banerjee & M. Phelps: A new method to estimate parameters of linear compartmental models using artificial neural networks, Phys. Med. Biol., 43, 1659-1678, 1998.
    15. Keppenne C.L., S. Marcus, M. Kimoto & M. Ghil: Intraseasonal variability in a two-layer model and observations, J. Atmos. Sci., 57, 1010-1028, 2000.
    16. Keppenne C.L.: Data assimilation into a primitive equation model using a parallel ensemble Kalman filter, Mon. Wea. Rev., 128, 1971-1981, 2000.
    17. Keppenne C.L. & M. Rienecker: Development and initial testing of a parallel Ensemble Kalman filter for the Poseidon isopycnal ocean general circulation model, Mon. Wea. Rev., 130, 2951-2965, 2002.
    18. Keppenne C.L. & M. Rienecker: Assimilation of temperature into an isopycnal ocean general circulation model using a parallel Ensemble Kalman filter, J. Mar. Sys., 41, 363-380, 2003.
    19. Keppenne C.L., M. Rienecker, N. Kurkowski & D. Adamec: Ensemble Kalman filter assimilation of altimeter and temperature data with bias correction and application to seasonal prediction, Nonlinear Processes in Geophysics, 12, 491-503, 2005.
    20. Borovikov A., M. Rienecker, C.L. Keppenne & G. Johnson: Multivariate error covariance estimates by Monte Carlo simulation for assimilation studies in the Pacific Ocean, Mon. Wea. Rev., 133, 2310-2334, 2005.
    21. Sun C., M Rienecker, A. Rosati, M. Harrison, A. Wittenberg, C.L. Keppenne, J. Jacob & R. Kovach: Comparison and sensitivity of ODASI ocean analyses in the Tropical Pacific, Mon. Wea. Rev., 135, 2242-2264, 2007.
    22. Reichle R., W. Crow & C.L. Keppenne: An adaptive ensemble Kalman filter for soil moisture data assimilation, Water Resources Research, 44, W03423, 2008.
    23. Keppenne C.L., M. Rienecker, J. Jacob & R. Kovach: Error covariance modeling in the GMAO ocean ensemble Kalman filter, Mon. Wea. Rev., 136, 2964-2982, 2008.
    24. Yang S., C.L. Keppenne, M. Rienecker & E. Kalnay: Application of coupled bred vectors to seasonal-to-interannual forecasting and ocean data assimilation, J. Climate, 22, 2850-2870, 2009.
    25. Yang S., M. Rienecker & C.L. Keppenne: The impact of ocean data assimilation on seasonal to interannual forecasts: A case study of the 2006 El Nin?o event, J. Climate, 23, 4080-4095, 2010.
    26. Keppenne C.L.: An ensemble recentering Kalman filter with an application to Argo temperature data assimilation into the NASA GEOS-5 coupled model, Ocean Modelling, 77, 50–55, 2014.
    27. Chang C., S. Yang & C.L. Keppenne: Applications of the mean recentering scheme to improve typhoon track prediction: A case study of Typhoon Nanmadol (2011), J. Meteor. Soc. Japan, 92, 559-584, 2014.
    28. Vernieres G., R. Kovach, C.L. Keppenne, L. Brucker & E. Dinnat: The impact of the assimilation of Aquarius sea surface salinity data in the GEOS ocean data assimilation system, J. Geophys. Res. Oceans,119, 69746987, 2014.  

    Academic dissertations and Technical Memoranda
    1. Keppenne C.L.: A Comprehensive Model of Shallow Overland Flow, M.S. Thesis, Catholic University of Louvain, 37pp., 1986.
    2. Keppenne C.L.: Bifurcations, Strange attractors, and Low-Frequency Atmospheric Dynamics, Ph.D. Dissertation, Catholic University of Louvain, 158pp., 1989.
    3. Keppenne C.L. & M. Rienecker: Design and Implementation of a Parallel Multivariate Ensemble Kalman Filter for the Poseidon Ocean General Circulation Model, NASA/TM-2001-104606, 21, 2001.
    4. Vernieres G., C.L. Keppenne, M. Rienecker, J. Jacob & R. Kovach: The GEOS-ODAS description and evaluation, NASA/TM-2012-104606, 30, 2012.
    5. Keppenne C.L., M. Rienecker, R. Kovach & G. Vernieres: Background Error Covariance Estimation using Information from a Single Model Trajectory with Application to Ocean Data Assimilation into the GEOS5 Coupled Model, NASA/TM-2014-104606, 34, 2014.

    Papers Presented at Scientific Meetings (to save space, listing only when Lead Author)
    1. Keppenne C.L. & M. Ghil: Adaptive Spectral Analysis of the Southern Oscillation Index, in Proc. of XVth Annual Climate Diagnostics Workshop, US Department of Commerce, NOAA, 1-35, 1990.
    2. Keppenne C.L., M. Ghil, A. Kowala, G. Fox, & J. Flower: Parallelization of an atmospheric general circulation model, in Proc. of International Workshop on Controlled Active Global Experiments, Societa Italiana di Fisica, 47-66, 1991.
    3. Keppenne C.L.: Meteorological Data Assimilation Using a Kalman Filter: Challenges and Rewards, in Proc. of Workshop on Data Systems for Parallel Climate Models, ANL/MCS-TM-169, Argonne National Laboratory, 195-198, 1992.
    4. Keppenne C.L. & M. Ghil: Intraseasonal Oscillations in the Northern Hemisphere: A Dynamical View, EOS Trans. AGU, 73, Spring Meeting Suppl., 47, 1992.
    5. Keppenne C.L. & M. Ghil: Singular spectrum analysis (SSA) and the maximum entropy method (MEM) applied to forecast the Southern Oscillation Index, in Experimental Long-Lead Forecast Bulletin, National Meteorological Center, NOAA, Vol. 1-3, No 1-4, 1992-1994.
    6. Keppenne C.L., J. Dickey, D. Boggs & M. Ghil: Global Climate Modeling Applied to Planetary Atmospheres, JPL D-10228, Jet Propulsion Laboratory, Pasadena, CA, 151-154, 1993.
    7. Keppenne C.L., M. Dettinger & M. Ghil: Spatio-temporal analysis of interannual fluctuations in the United States surface-air temperature record, EOS Trans. AGU, 74, Fall Meeting Suppl., 123, 1993.
    8. Keppenne C.L. & M. Ghil: Intraseasonal oscillations in a two-layer model, EOS Trans. AGU, 75, Fall Meeting Suppl., 130, 1994.
    9. Keppenne C.L.: Orographically forced oscillations in the Martian atmosphere, in NAS Technical Summaries, March 1992-February 1993, NASA RP-132110, 123, 1994.
    10. Keppenne C.L.: Intraseasonal Atmospheric Oscillations, in NAS Technical Summaries, March 1993-February 1994, NASA RP-1355, 97, 1995.
    11. Keppenne C.L.: The El Nino/Southern Oscillation and agricultural commodity futures, EOS Trans. AGU, 76, Spring Meeting Suppl., 175, 1995.
    12. Keppenne C.L. & U. Lall: A new methodology to forecast paleoclimate time series with applications to the Southern Oscillation Index, EOS trans. AGU, 76, Fall Meeting Suppl., 327, 1995.
    13. Keppenne C.L. & U. Lall: Forecast of the Southern Oscillation Index using complex singular spectrum analysis (CSSA) and multivariate adaptive regression splines (MARS), in Experimental Long-Lead Forecast Bulletin, National Meteorological Center, NOAA, Vol. 4, No 1-4, 1995.
    14. Keppenne C.L., I. Fukumori & M. Ghil: Assimilation of altimeter data in a primitive-equation model of the Equatorial Pacific using an ensemble Kalman filter, 1996 Data Assimilation and Modeling Evaluation Experiment (DAMEE) North Atlantic Basin (NAB) Meeting, held at Miami, March 18-21, 1996.
    15. Keppenne C.L., M. Rienecker & M. Suarez: Reconstruction of the 97/98 El Nino from TOPEX and TOGA /TAO measurements using a massively parallel isopycnal ocean model and data assimilation system, Fall Meeting of the American Geophysical Union, held at San Francisco, December 6-10, 1998.
    16. Keppenne C.L. & M. Rienecker: A parallel ensemble Kalman filter, 24th General Assembly of the European Geophysical Society, held at Den Haag, Netherlands, April 19-23, 1999.
    17. Keppenne C.L. & M. Rienecker: Massively parallel sequential assimilation of temperature data from the TAO array into an ocean general circulation model, 3rd World Meteorological Organization Symposium on the Assimilation of Observations in Meteorology and Oceanography, held at Quebec, Canada, June 7-11, 1999.
    18. Keppenne C.L. & M. Rienecker: Assimilation of temperature into an ocean general circulation model using a massively parallel ensemble Kalman filter, Workshop on Advanced Data Assimilation Methods, held at Corvallis, Oregon, July 28-30, 1999.
    19. Keppenne C.L. & M. Rienecker: Assimilation of satellite altimetry into a global ocean general circulation model using a parallel ensemble Kalman filter, 25th General Assembly of the European Geophysical Society held at Nice, France, April 25-29, 2000.
    20. Keppenne C.L. & M. Rienecker: Identical-twin assimilation of altimetry into an ocean circulation model using a parallel ensemble Kalman filter, Spring Meeting of the American Geophysical Union, held at Washington, DC, May 30-June 3, 2000.
    21. Keppenne C.L. & M. Rienecker: Parallel assimilation of altimeter data and in situ temperature data into quasi isopycnal ocean general circulation model, 26th General Assembly of the European Geophysical Society held at Nice, France, March 26-30, 2001.
    22. Keppenne C.L. & M. Rienecker: Validation of a parallel ensemble Kalman filter for seasonal to interannual forecasting, 2001 Liege Colloquium on Ocean Hydrodynamics held at Liege, Belgium, May 7-11, 2001.
    23. Keppenne C.L. & M. Rienecker: Multivariate assimilation of altimetry into an OGCM with diagnostic sea surface height using the ensemble Kalman filter, proc. of Symposium on Observations, Data Assimilation and Probabilistic Prediction held at Orlando, January 13-17, 2002, 158-163, Amer. Met. Soc., 2002.
    24. Keppenne C.L. & M. Rienecker: An ensemble Kalman filter for seasonal-to-interannual forecast applications, "En route vers GODAE" Symposium held at Biarritz, France, June 14-17, 2002.
    25. Keppenne C.L. & M. Rienecker: Assimilation of TOPEX/Poseidon altimeter data into a global OGCM with an ensemble Kalman filter, 5th Symposium on Integrated Oberving Systems held at Long Beach, CA, February 10- 14, 2003.
    26. Keppenne C.L. & M. Rienecker: Initial results from the assimilation of sea-surface height anomalies into the NSIPP global ocean model using the ensemble Kalman filter, 2nd Workshop on Ensemble Based Assimilation held at Camp Springs, MD, March 18-20, 2003.
    27. Keppenne C.L. & M. Rienecker: Validation of a massively parallel ensemble Kalman filter with a 1/3-degree, 27-layer global OGCM, 2003 General Assembly of the European Geophysical Society, held at Nice, France, April 7-11, 2003.
    28. Keppenne C.L., M. Rienecker & N. Kurkowski: Initialization of seasonal forecasts with the ensemble Kalman filter, Meeting on Ensemble Forecasting Methods, held at Valmorin, QC, Canada, September 18-20, 2003.
    29. Keppenne C.L., M. Rienecker & N. Kurkowski: Hindcasting the 2002 El Nino event by means of a coupled model initialized with a multivariate ensemble Kalman filter, Symposium on Forecasting the Weather and Climate of the Atmosphere and Ocean, held at Seattle, WA, January 11-15, 2004.
    30. Keppenne C.L., M. Rienecker, N. Kurkowski, R. Kovach & D. Adamec: Use of the ensemble Kalman filter in the GMAO coupled forecasting system, 2004 General Assembly of the European Geophysical Union, held at Nice, France, April 26-30, 2004.
    31. Keppenne C.L., M. Rienecker, N. Kurkowski & D. Adamec: Ensemble Kalman filtering of temperature and altimetry data in 3 X 10^7 state dimensions with online bias correction and application to seasonal forecasting, 13th AMS Conference on Satellite Meteorology and Oceanography, held at Virginia Beach, VA, September 20- 24, 2004.
    32. Keppenne C.L., M. Rienecker & N. Kurkowski: Temperature and altimetry assimilation into a high resolution OGCM with a localized ensemble Kalman filter and impact on seasonal forecasts, 9th Symposium on Integrated Observing Systems and Data Assimilation, held at San Diego, CA, January 9-13, 2005.
    33. Keppenne C.L., M. Rienecker, J. Jacob & R. Kovach: Temperature and altimetry assimilation into a high resolution OGCM with a localized ensemble Kalman filter, 2006 American Geophysical Union Ocean Sciences Meeting, held at Honolulu, HI, February 20-24, 2006.
    34. Keppenne C.L., M. Rienecker, N. Kurkowski, J. Jacob & R. Kovach: Ensemble data assimilation and its impact on seasonal prediction skill, 2006 General Assembly of the American Geophysical Union, held at Baltimore, MD, May 23-26, 2006.
    35. Keppenne C.L., M. Rienecker, J. Jacob, R. Kovach & J. Marshak: Use of the ensemble Kalman filter in a global coupled seasonal prediction system: impact on prediction skill and other issues, 11th Symposium on Integrated Observing and Assimilation Systems for the Atmosphere, Oceans, and Land Surface, held at San Antonio, TX, January 14-18, 2007.
    36. Keppenne C.L.: The GMAO ocean data assimilation system and the assimilation of altimetry data, Joint Center for Satellite Data Assimilation 5th Science Workshop, held at College Park, MD, May 1-2, 2007.
    37. Keppenne C.L., M. Rienecker, J. Jacob & R. Kovach: Error covariance modeling in low-order ensemble filters, 2nd Clivar/GODAE Meeting on Ocean Synthesis Evaluation, held at MIT, Cambridge, MA, October 24-26, 2007.
    38. Keppenne C.L., M. Rienecker, R. Kovach & J. Jacob: Use of the ensemble Kalman filter in a global coupled seasonal prediction system, American Geophysical Union Ocean Sciences Meeting, held at Orlando, FL, March 2-7, 2008.
    39. Keppenne C.L., M. Rienecker & J. Jacob: The NASA/GMAO coupled data assimilation effort, 3nd Clivar/GSOP Meeting, held at JAMSTEC, Tokyo, Japan, October 6-8, 2008.
    40. Keppenne C.L., G. Vernieres, M. Rienecker, R. Kovach, J. Jacob & J. Marshak: Ocean Data Assimilation into the GEOS-5 Coupled Model with the GMAO Coupled Ensemble Analysis System, American Geophysical Union Ocean Sciences Meeting, held at Portland, OR, February 22-26, 2010.
    41. Keppenne C.L., G. Vernieres, M. Rienecker & R. Kovach: Ensemble Data Assimilation of Ocean Data into the GEOS-5 Coupled Model, invited lecture given at the NOAA Environment Modeling Center, Camp Springs, MD, June 15, 2010.
    42. Keppenne C.L., G. Vernieres, R. Kovach & M. Rienecker: Look Ma, no EnKF! Ensemble Data Assimilation without Ensembles, 4th World Climate Research Programme Conference of Reanalyses, held in Silver Spring, MD, May 7-11, 2012.
    43. Keppenne C.L., G. Vernieres, M. Rienecker & R. Kovach: Ensemble Data Assimilation without Ensembles with Application to Ocean Data Assimilation, 6th World Meteorological Organization Symposium on Data Assimilation, held in College Park, MD, October 7-11 2013.
    44. Keppenne C.L., S. Akella, M. Keppenne, R. Kovach, R. Todling, G. Vernieres, Y. Vikhliaev & B. Zhao: High Resolution Ocean and Sea Ice Data Assimilation with Weak Coupling to Atmospheric Analysis in the NASA GEOS-5 Coupled Modeling System, invited lecture to the Symposium on Coupled Data Assimilation organized by the Chinese Academy of Sciences and the World Meteorological Organization Symposium, held in Beijing, China, July 5-8 2015.

    Awards

    NASA Laboratory for Hydrospheric Processes Peer Award 2001 
    Awarded for outstanding development of NASA seasonal to interannual prediction project (NSIPP) ocean data assimilation system in a massively parallel computing environment and for leading ocean data assimilation research in a quasi-operational framework

    NASA GMAO/SRT Outstanding Performance Award 2004
    Recognition for (1) outstanding leadership and support for the GMAO ocean data assimilation effort and unified software implementation of ensemble Kalman filter (EnKF) and multivariate optimal interpolation (MvOI) schemes used by the GMAO and (2) demonstrating the importance of online bias correction in the assimilation of sea surface height anomalies in the GMAO seasonal forecasting system leading to improved seasonal forecasts

    GMAO/SRT Outstanding Performance Award 2005
    Recognition for outstanding leadership in ocean data assimilation within the GMAO

    NASA GMAO Outstanding Performance Award 2009
    For leadership in the GMAO data assimilation group and outstanding performance in the development of the ensemble Kalman filter (EnKF) data assimilation system within the GEOS-5 atmosphere-ocean general circulation model

    NASA GMAO/SSAI Outstanding Performance Award 2012
    Awarded for involvement in team effort in preparing ocean, sea ice and land initial conditions for the NASA GEOS-5 seasonal and decadal predictions.

    Brief Bio

    Christian Keppenne is a senior expert level computational scientist with expertise in algorithm development, parallel scientific computing, numerical and statistical modeling, machine learning and many other areas of numerical analysis. He has authored numerous peer-reviewed articles and has presented his work at more than 50 scientific conferences. Dr. Keppenne leads the NASA Global Modeling and Assimilation Office (GMAO) ocean data assimilation system development effort at the NASA Goddard Space Flight Center (GSFC) where he develops and maintains the integrated Ocean data assimilation system (iOdas) and the ocean data assimilation component of the GMAO integrated Earth System Analysis (IESA) effort. iOdas is used routinely to initialize ensembles of coupled seasonal forecasts and experimentally in global high resolution coupled numerical weather prediction and tropical cyclone forecasting applications.

    Main areas of expertise and interests:

    • High performance parallel scientific computing
    • Remote sensing, inverse modeling and data assimilation
    • Numerical climate modeling
    • Statistical analysis, modeling and prediction of data including time series analysis and prediction, machine learning, genetic algorithms and recommender systems
    • Software development in C/C++, modern Fortran, Java, Javascript, Python, Perl, Scala, R External profiles:
    linkedin
    researchgate
    google scholar

                                                                                                                                                                                            
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