Could the two anticyclonic eddies during winter 2003/2004 be reproduced and predicted in the northern South China Sea?
Great progress has been made in understanding the mesoscale eddies and their role on the large-scale structure and circulation of the oceans. However, many questions still remain to be resolved, especially with regard to the reproductivity and predictability of mesoscale eddies. In this study, the reproductivity and predictability of mesoscale eddies in the northern South China Sea (NSCS), a region with strong eddy activity, are investigated with a focus on two typical anticyclonic eddies (AE1 and AE2) based on a HYCOM–EnOI assimilated system. The comparisons of assimilated results and observations suggest that generation, evolution, and propagation paths of AE1 and AE2 can be well reproduced and forecasted when the observed amplitude is >8 cm (or the advective nonlinearity parameter U∕c is >2), although their forcing mechanisms are quite different. However, when their amplitudes are less than 8 cm, the generation and decay of these two mesoscale eddies cannot be well reproduced and predicted by the system. This result suggests, in addition to dynamical mechanisms, that the spatial resolution of assimilation observation data and numerical models must be taken into account in reproducing and predicting mesoscale eddies in the NSCS.