HR: 1340h
AN: NG43B-0586    [Abstracts]
TI: Geomagnetic Data Assimilation Using Ensemble Error Covariance Estimation
AU: * Sun, Z
EM: sunzhib1@umbc.edu
AF: Dept. Math, University of Maryland-Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 United States
AU: Tangborn, A
EM: tangborn@gmao.gsfc.nasa.gov
AF: JCET, University of Maryland-Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 United States
AU: Kuang, W
EM: kuang@bowie.gsfc.nasa.gov
AF: Space Geodesy Branch, Code 697, Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Liu, D
EM: dliu@bowie.gsfc.nasa.gov
AF: JCET, University of Maryland-Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 United States
AU: Jiang, W
EM: jiangw@umbc.edu
AF: JCET, University of Maryland-Baltimore County, 1000 Hilltop Circle, Baltimore, MD 21250 United States
AB: We outline the development of a geomagnetic data assimilation system in which the error covariances are calculated using an ensemble of model solutions. The MoSST core dynamics model is used with perturbed initial conditions to construct time varying error covariances. These covariances are especially important in geomagnetic data assimilation because only part of the poloidal magnetic field (up to degree L = 13) are observable at the Earth's surface. The error covariances indicate not only how the poloidal magnetic field deep inside the core should be corrected by the surface observations, but also how other physical variables, i.e. the remaining poloidal field, the toroidal magnetic field, the velocity field and the density perturbation should be corrected. This "balanced" approach to correcting the core state is less likely to cause non-physical oscillations or instabilities in the response. We will show the time varying error covariances between the poloidal magnetic field and the other state variables along with some initial assimilation results.
DE: 0560 Numerical solutions (4255)
DE: 1510 Dynamo: theories and simulations
DE: 3315 Data assimilation
SC: Nonlinear Geophysics [NG]
MN: Fall Meeting 2005