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

Abstract. A comparison of the Naval Research Lab Layered Ocean Model (NLOM) nowcast fields with independent 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 this dynamical inconsistency is caused by a low data coverage for assimilation at the time of the cruise in combination with the data assimilation technique, that treats sea surface height and sea surface temperature data independently.