OVERVIEW: High Frequency (HF) radar systems have successfully used to monitor ocean currents, and more recently ultra-high frequency (UHF) radar systems have been used to monitor river currents. During Nov - Dec 2005, a CODAR RiverSonde ultra-high frequency (UHF) radar system was installed at the Baruch Institute at Georgetown, SC to determine the feasibility of using an UHF radar to record currents in an estuarine environment. Radar systems offer many advantages over traditional instrumentation, since they are able to record data from a large area, rather than just a single point location. Additionally, radar systems are land-based, and thus not subject to hazards that submersible instruments face.

OBJECTIVES:

1. To determine which environmental and meteorological factors affect the accuracy of the RiverSonde system (UHF radar).

2. To determine how the performance of the RiverSonde system compares to that of a traditional ADCP.

UHF RADAR BACKGROUND:

For more information about the background of HF / UHF radar systems and the principles of operation, visit our HF Radar page.

CODAR Ocean Sensors, Ltd produced the UHF radar system, called the RiverSonde, that was used in this experiment. Visit CODAR's webpage to learn more details about principles of operation of the RiverSonde system.

STUDY SITE MAP:

	This picture shows the complete, operational RiverSonde system mounted a boardwalk overlooking the marsh at the Baruch Institute. The tower is approximately 3 meters tall, with three antenna arms. The RiverSonde system emits radar signals over the marsh, and the roughness caused by surface waves reflects the radar signals back to the system. The velocity of the surface waves can be calculated based on the Doppler shift of the returning signal.
	This figure shows the complete coverage range of the RiverSonde system, a semi-circular swathe with a 300 meter radius. This range included the main tidal channel, small tidal creeks, and regions of the marsh platform.Since this was a validation study, an ADCP was deployed in the main tidal channel approximately 100 m from the RiverSonde system. Since the RiverSonde takes thousands of readings throughout the coverage zone simultaneously, in order to compare the readings from these two instruments we only used radar readings from a small region surrounding the ADCP.
	Steven Traynum configuring the ADCP before deployment.
	Dr. Rich Styles, shown here, as well as Calvin Teague and Don Barrick, both from CODAR Ocean Sensors, were primary investigators in this study.
	A view of a small tidal creek, with the Baruch Institute in the background. Note the abundance of Spartina grass over the marsh platform. Even at high tide, Spartina protrudes above the surface of the water, creating an ideal radar target. Thus, inaccurate readings due to backscatter from vegetation proves to be a significant challenge when using radar systems in an inter-tidal environment.

View our results HERE