Sequential forecasting of the surface and subsurface conditions in the Japan Sea

Hirose, Naoki*; Kawamura, Hideyuki  ; Lee, H. J.*; Yoon, J.-H.*

This study estimates and forecasts a realistic change of the Japan Sea by assimilating satellite measurements into an eddy-resolving circulation model. Suboptimal but feasible assimilation schemes of approximate filtering and nudging play essential roles in a system. The sequential updates of error covariance significantly outperforms the asymptotic covariance due to irregular sampling patterns from multiple altimeter satellites. The best estimate shows an average rms difference of 1.2 C only to the radiometer data, and also explain about half of sea level variances measured by the microwave observation. It is demonstrated that a forecast persistency strongly depends on variable, depth, and location.