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.