Jr. Gunson et P. Malanotterizzoli, ASSIMILATION STUDIES OF OPEN-OCEAN FLOWS .2. ERROR MEASURES WITH STRONGLY NONLINEAR DYNAMICS, J GEO RES-O, 101(C12), 1996, pp. 28473-28488
In a companion paper by Gunson and Malanotre-Rizzoli [this issue], the
problem of estimating boundary and initial conditions for a regional
open-ocean model from sparse data is addressed using the adjoint metho
d. Here the estimation of error covariances for the estimated boundary
and initial conditions and interior fields, in the presence of strong
ly nonlinear dynamics, is investigated. The evaluation of the full err
or covariance matrix for the estimated control variables from the inve
rse Hessian matrix is presented along with its dependence upon the deg
ree of nonlinearity in the dynamics. Major new results here obtained a
re the availability of off-diagonal covariances, the successful calcul
ation of error covariances for all boundary and initial conditions, an
d the estimation of errors for interior fields. The role of the Hessia
n matrix is assessed in gauging the sensitivity of the estimated bound
ary and initial conditions to the data.