2016 - 2021: Assistant Chief, Global Modeling and Assimilation Office
2014 - 2021: Member, GMAO Strategic Management Team
2008 - 2009: Member, International Scientific Organizing Committee, Fifth WMO International Symposium on Data Assimilation, Melbourne, Australia
2005: Guest Editor, Quarterly Journal of the Royal Meteorological Society
2004 - 2005: Co-Chair, International Program Committee, Fourth WMO International Symposium on Assimilation of Observations in Meteorology and Oceanography, Prague, Czech Republic
2003 - 2008: Editor, Monthly Weather Review
2002 - 2003: Member, Scientific Committee, Roger Daley Memorial Symposium, Montreal, Canada
2002: Lecturer, NATO Advanced Study Institute (ASI) on Data Assimilation for the Earth System, Maratea, Italy
2000 - 2002: Chief Scientist for Analysis, Data Assimilation Office, GSFC
2000 - 2001: Ph.D. Thesis Supervisor (Tijana Janjic), University of Maryland College Park
2000 - 2001: Special Faculty, University of Maryland College Park
1998 - 2000: Associate Editor, Monthly Weather Review
1995: Member, Scientific Committee, Second UNAM-Cray Supercomputing Conference on Numerical Simulations in the Environmental and Earth Sciences, Mexico City, Mexico
1993 - 1998: Lead Scientist for GEOS Data Assimilation System Development, GSFC
1993 - 1995: Fellow, Joint Center for Earth System Science
1992, 2002: Branch Representative, Summer Institute on Atmospheric and Hydrospheric Sciences
1992 - 1998: Chair, GSFC Library Committee
1992 - 1994: Chair and Founding Member, Goddard Mathematics Group