Evaluation of a UHF Radar Surface Current Mapping System in an Intertidal Salt Marsh

Abstract

A UHF RiverSonde radar system was deployed in an intertidal salt marsh during November and December 2005 near Georgetown, South Carolina. The purpose of this experiment was to evaluate radar performance in a coastal plain salt marsh, where the channels are highly sinuous and the flow is dominated by tides. To help evaluate radar performance, an acoustic current profiler was placed in a large subtidal channel located in the field of view of the radar. Comparisons indicated that the radar accurately reproduced both the magnitude and phasing of the surface current. Spatial coverage was generally good in the channels but much more sporadic over the marsh platform. Temporal coverage in the channel was also good and correlated with wind speed. Reliable measurements were obtained under wind speeds as low as 2?3 m s?1, which are common at this site. In addition, some unexpected signals were seen at near zero Doppler shift, which were attributed to the saltwater vegetation Spartina alterniflora, which acted as effective radar targets. However, these signals were uncorrelated and likely can be filtered.