Comparison of a NLOM data assimilation product to direct measurements in the Antarctic Polar Frontal Zone: a case study

An independent comparison of the Naval Research Lab Layered Ocean Model (NLOM) nowcast fields with in-situ observations from a cruise in the Polar Frontal Zone of the Atlantic Sector of the Southern Ocean is presented. NLOM sea surface temperature fields can be used to determine the position of fronts and individual eddies, whereas the analyzed sea surface height appears to be out of phase. It is suggested that a combination of low data coverage for assimilation of the model at the time of the cruise and the data assimilation technique causes this inconsistency.