JPL Technical Report Server

An Approximate Kalman Filter for Ocean Data Assimilation; An Example with an Idealized Gulf Stream Model

Show simple item record Fukumori, Ichiro en_US Malanotte-Rizzoli, Paola en_US 2004-10-01T17:41:47Z 2004-10-01T17:41:47Z 1994-11-14T17:41:47Z
dc.identifier.citation Journal of Geophysical Research en_US
dc.identifier.clearanceno 95-0033
dc.description.abstract A practical method of data assimilation for use with large, nonlinear, ocean general circulation models is explored. A Kalman filter based on approximations of the state error covariance matrix is presented, employing a reduction of the effective model dimension, the error's asymptotic steady-state limit, and a time-invariant linearization of the dynamic model for the error integration. The approximations lead to dramatic computational savings in applying estimation theory to large complex systems. We examine the utility of the approximate filter in assimilating different measurement types using a twin experiment of an idealized Gulf Stream. A nonlinear primitive equation model of an unstable east-west jet is studied with a state dimension exceeding 170,000 elements. Assimilation of various pseudo measurements is examined, including velocity, density, and volume transport at localized arrays, and realistic distributions of satellite altimetry and acoustic tomography observations. Results are compared in terms of their effects on the accuracies of the estimation. The approximate filter is shown to outperform a previous study that used an empirical nudging scheme. The examples demonstrate that useful approximate estimation errors can be computed in a practical manner for general circulation models. en_US
dc.format.extent 1233944 bytes
dc.format.mimetype application/pdf
dc.language.iso en_US
dc.subject.other Kalman Filter en_US
dc.subject.other Ocean General Circulation Models en_US
dc.title An Approximate Kalman Filter for Ocean Data Assimilation; An Example with an Idealized Gulf Stream Model en_US

Files in this item

This item appears in the following Collection(s)

Show simple item record



My Account