HR: 1340h
AN: NG43B-0587    [Abstracts]
TI: Core Flow Response to Surface Magnetic Field Observations
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 Laboratory, Code 697, Goddard Space Flight Center, Greenbelt, MD 20771 United States
AB: In geomagnetic data assimilation, only surface observations of the magnetic field are available to make corrections to the core state. In the absence of correlations between the errors in the different state variables (velocity, temperature and magnetic field), coupling between observations and the core flow is through the Lorenz force term in the Navier-Stokes equation. In this work, we examine the changes to the core flow that occur after assimilating magnetic observations. We have carried out a model run that assimilates surface observations every 20 years, from 1900 to 2000 and analyze the response of the core flow to each of 5 assimilation cycles. We find that the response of the surface magnetic field after the first assimilation diverges from the observed values more rapidly than responses to later assimilation cycles. We will show what changes in the core flows that could possibly be leading to this improvement in the magnetic field forecast.
DE: 0560 Numerical solutions (4255)
DE: 1510 Dynamo: theories and simulations
DE: 3315 Data assimilation
SC: Nonlinear Geophysics [NG]
MN: Fall Meeting 2005