present Space Weather Prediction Center, NOAA Physicist/Ionosphere modeling and services 1991 - 2005 CIRES/University of Colorado at Boulder Research Scientist–Thermosphere/Ionosphere Modeling 1989 - 1991 University College London/University of Southampton, UK Research Assistant–Thermosphere/Ionosphere Coupling 1986 - 1989 National Center for Atmospheric Research/High Altitude Observatory Graduate Research Assistant–System theory approach to a large nonlinear computer model of the Thermosphere/Ionosphere SystemFor his Ph.D., Dr. Codrescu used the NCAR three-dimensional, time-dependent thermospheric model (TGCM) to study the importance of an interactive ionosphere in thermosphere simulations. In 1991 he accepted a position with the Cooperative Institute for Research in Environmental Sciences at the University of Colorado at Boulder. Dr. Codrescu joined NOAA's Space Environment Center in Boulder, CO in 2005. He is interested in understanding and quantifying the response of the upper atmosphere to auroral precipitation and to the magnetosphere electric field. He has recently become involved with data assimilation techniques and the application of metrics to quantify our ability to specify and forecast the upper atmosphere. Dr. Codrescu has published over 40 scientific papers in refereed journals and has presented numerous talks at national and international meetings.Specialties: Space Weather, Ionosphere, GPS positioning