Radar Ocean Sensing Laboratory (ROSL)

The RSMAS Radar Ocean Sensing Laboratory (ROSL) is an interdisciplinary research group primarily based in the Division of Applied Marine Physics of the Rosenstiel School, but with additional members in Meteorology and Physical Oceanography. Its research efforts involve the use of a land-based Doppler radar to measure surface vector currents in the coastal ocean and airborne and satellite observations of different radar sensors such as wind speed and direction from scatterometers [SEASAT, ERS-1 and NSCAT], wave height and wind speed from altimeters [SEASAT, GEOSAT, ERS-1 and TOPEX/POSEIDON], and directional wave spectra and backscatter images from synthetic aperture radars [JPL/INSAR, SEASAT, and ERS-1]. The research and graduate education of ROSL complements the satellite oceanography activities of the Remote Sensing Group.


OSCR

ROSL owns and operates a dual-frequency ocean surface current radar (OSCR) which utilises HF (25.4 MHz) and VHF (49.9 MHz) radio frequency to map surface current patterns over a large area in the coastal ocean. The shore-based radar system consists of two units (Master and Slave) which are usually deployed several kilometers apart. Each unit makes independent measurements of current speed along radials emanating from its phased-array antenna system. The data are then combined via UHF or telephone communication to produce accurate vector currents (speed and direction) and display them in near real time. The measurements can be made simultaneously at up to 700 grid points either at 1 km (HF mode) or 250 m (VHF mode) resolution. The measurement interval for one vector current map is repeated every 20 minutes.

	      OSCR System Capabilities and Specifications
	----------------------------------------------------------
        	                                    HF        VHF
	----------------------------------------------------------
	Frequency (MHz)                             25.4      49.9
	Resolution  (km)                             1        0.25
	Range* (km)                                  40        10
	Measurement cycle (min)                      20        20
	Spatial coverage*  (km^2)                   700        70
	Max number of measurements points*          700       700
	Measurement depth (cm)                       40        20
	Data Storage (days)                         120       120
	---------------------------------------------------------
	Transmitter Peak Power (KW)                   1       0.1
	Transmitter Average Power (W)                 2        2
	Power Consumption (KW @ 240V)                 1        1
	Transmit antenna elements (Yagi; 6dB gain)    4        4
	Receive antenna elements (phased array)      16       32
	Pulse length
	Pulse repetition frequency
	---------------------------------------------------------
	Accuracy:
  	Radial current (cm/s)                         2        2
  	Vector current (cm/s)                         4        4
  	Vector direction (max deg)                    5        5
	---------------------------------------------------------

Research Program

The present program supports multi-disciplinary research projects funded by the Office of Naval Research (ONR), the National Aeronautics and Space Administration (NASA), the US Coast Guard, the Minerals and Management Service (MMS), the Naval Research Laboratory (NRL), and the US Army Corps of Engineers (USAE). The NASA efforts center around the pre-launch development of a wind retrieval model function which includes the effects of sea sate and the development of algorithms to detect and quantify the occurence of extreme waves or so-called ``rogue waves'' using SAR imagery. The Coast Guard project funded through the UM Ocean Pollution Research Center is concerned with new techniques to monitor remotely surface currents in in coastal waters. The ONR program is focused on understanding the physics responsible for imaging mesoscale surface features by radar. The NRL supports a study to examine the feasibility of utilising the OSCR system on a ship. The MMS effort investigates the temporal and spatial variability of the coastal circulation. The Army Corps of Engineers supported a study on using airborne interferometry for computing surface current patterns along the coast.

A cluster of SUN workstations networked by ethernet and several PCs facilitate the computing system for data processing and analysis of scatterometer and altimeter data, radar images and remotely sensed surface current fields. The computing system is linked to high speed networks (2 T1 links to the Internet).


Faculty

Hans C. Graber
Associate Professor [AMP/MPO] (surface wave dynamics, microwave remote sensing of ocean processes, air-sea interaction and boundary-layer dynamics)
Lynn K. Shay
Associate Professor[MPO] (air-sea interactions, ocean response to atmosphere forcing aircraft-based ocean measurements)

Staff

Brian K. Haus
Associate Scientist[AMP] (ocean surface-layer dynamics, radar measurments of surface waves, coastal circulation)
Jorge Martinez
Research Associate (Field operations and data processing)

Contact Information

Prof. Hans Graber
RSMAS - University of Miami
4600 Rickenbacker Causeway
Miami, FL 33149

tel: 305/361-4935
fax: 305/361-4701
hgraber@rsmas.miami.edu
Last Revised: 31 August 2000