My colleagues in Bergen, Norway, in an effort led by my former student Yiguo Wang, have published a paper in Ocean Modelling. I have helped edited the paper and reviewed the data assimilation advances of the study. The paper explains how to assimilate hydrographic profiles into an isopycnal ocean using the EnKF. The study is based on the Norwegian Climate Prediction Model and the EnKF.
First, the study shows that it is best to assimilate the observations using their z-level coordinates rather than the isopycnal coordinates, which answers a difficult question in the field. Second, the localisation radius is geographically adapted and its impact tested. Third, the instrumental and representativeness errors are estimated based on a fine theoretical statistical analysis.