Ship borne remote sensing of submesoscale oceanographic features along the northern boundary of the Gulf Stream

摘要

The authors made low grazing angle coherent radar measurements of submesoscale oceanographic features off the coast of Cape Hatteras using a dual polarized X-band radar with a range resolution of 3.75 m. They deployed the radar oh the USNS Bartlett and collected data from numerous features such as eddies, slicks, internal waves and temperature, salinity and current fronts. From the coherent backscatter data they compute backscatter power and surface flow velocity fields and use the surface flow velocity fields to determine the existence of current shear across the submesoscale features. The authors describe the experiment and present backscatter power and surface flow velocity fields for two fronts sampled on 22 June, 1993. The first set of results is for the northern front of a wedge of rough green water and the second set of results is for a front separating rough green water to the northwest and calmer blue water to the southeast of the front. The results show that a variability of 60 cm/s in the surface flow velocity exists across the first feature and a variability of 50 cm/s across the second feature, suggesting the existence of current shear across these features.