Frontal surveys with a towed profiling conductivity /temperature/depth measurement package (SeaSoar)

In April 1986, RV Oceanus participated in the Frontal Air-Sea Interaction Experiment (FASINEX1) in the region 27-29 N, 68-71 W. The objective was to survey a pronounced oceanic front2–4 and its effect on the oceanic and atmospheric boundary layers. Although moorings have yet to be recovered, and much of the data analysis is as yet only preliminary, it is possible to report here the typical density structure of a front as derived from SeaSoar5,6 (Fig. 1a) observations, which were analysed within a few hours of collection. Previously unreported detail is revealed, including subducted pycnostads (areas of weak vertical density gradient) with anomalous temperature/salinity signature, splitting of the frontal jet and three-dimensional structure not apparent in the surface temperature field.