The twin
assimilation experiments indicate that the effectiveness of a data assimilation
method depends on initial perturbation.
For the imperfect
initial condition case in which the T/S fields are perturbed, the EnKF works
efficiently in restoring the true ocean state (RMS errors reduce by 75% over a
time scale of ~10 days).
For imperfect model configuration case in which the wind
and heat flux fields are perturbed, the EnKF is constrained more by wind field
than heat flux. In winter, the wind dominates the effectiveness,while in
summer, both wind and heat flux seem equally important.
Since the data
assimilation works only under small e values, it is more important to improve
the accuracy of the forcing driving the model before the data
assimilation is used.