Scripps Institution of Oceanography
Initial information package requesting installation of
Surface Current Mapping antennas on San Clemente
Island at Stone Station or SPAWAR facility
Scripps Institution of Oceanography Points of Contact:
Lisa Lelli: (858) 822-2060
Operations Manager
Coastal Observing Research and Development Center
[email protected]
Eric Terrill: (858) 822-3101
Director
Coastal Observing Research and Development Center
[email protected]
www.sccoos.org
www.sdcoos.ucsd.edu
Scripps Institution of Oceanography
SCCOOS
Southern California Coastal Observing System
•
Project Overview
– The Southern California Coastal Observing System - Shelf to Shoreline Observatory Development
has been funded by NOAA to provide long range ocean current monitoring infrastructure for the
region, providing near real-time data products made openly available to a broad end-user community.
•
CODAR Element
– The system elements proposed to meet project goals includes a network of CODARS (Coastal Ocean
Dynamics Applications Radar).
–
The measurement principle for surface current mapping systems is based upon transmitting radio
waves and reflecting them from the ocean’s surface. The radio wa ves are tuned to a specific length of
ocean wave are transmitted from an antenna on shore, scattered o ff the ocean surface, and
subsequently received by another antenna next to the transmitter. The received radio signal, when
appropriately processed, allows the determination of currents at different ranges and angles in a
radial pattern centered at the radio antennas. Combining data from multiple systems that are
deployed along the coast allow the determination of both the northerly and easterly currents.
–
Optimal operation of the small-footprint radio antennas requires them to be placed near the water’s
edge to allow a broad field of view of the ocean.
–
More details regarding the principles behind HF radar based measurement of ocean currents can be
found at: http://www.sccoos.org/technology.shtml
Scripps Institution of Oceanography
Example Product
24hr averaged ocean currents, 2/25/03
CODAR is a low power radio technique used to map
ocean surface currents. Data is provided in near realtime for oceanographic studies, oil spill response,
search and rescue, aid to water quality assessments,
and integration into Regional Ocean Modeling
System.
Shown is an example product of surface currents
combined from four deployed stations. Data is
available at www.sdcoos.ucsd.edu for the San Diego
Region.
A long range system deployed on San Clemente will
allow ocean current mapping to extend offshore
70nm.
Scripps Institution of Oceanography
Potential Coverage map from system
deployed on San Clemente Island
Scripps Institution of Oceanography
Surface current vector
maps enabled when
combined with other long
range sites. Shown here
are overlaps for San
Clemente and Point Loma
Scripps Institution of Oceanography
Radio Antenna Specifications for Surface Current Mapping
l
Long Range Antennas (qty. 2)
1) Transmit Antenna
l 43 feet high
l
typically requires guy wire supports
2)
l
Receive Antenna
l 20 feet high
l four 8’ radial elements extend horizontally at a height of 12’
l one 8’ vertical element extends at a height of 12’
l guy wire supports
Electronic enclosure
l typical dimensions are 126Hx63Wx85D cm enclosure
l requires ~ 300 watts AC
l network connection required
Scripps Institution of Oceanography
Signal Specifications
Output Radiated Power: 80 watts peak, 40 watts average
Operating Frequency Range: 4.3 - 5.4 MHz
Modulation Format: Pulsed Swept Frequency CW
Pulse Repetition Frequency: 256 -512 Hz
Duty Factor: 50%
Sweep Width: 12 - 25 kHz (typical)
Sweep Repetition Frequency: 1 Hz
Total Radiated Signal Bandwidth (at - 20 dB level): 27 - 40 kHz
Polarization: vertical
Transmitter: SSTX 100
Input RF Drive Level: 0 dBm
Output RF Power Level: 100 watts peak, 50 watts average
Required Power: one of either 120 VAC or 220 VAC; 50-60 Hz, 300 watts
Design (gated FET): modular; all solid state
Operation: Class AB
Receiver: SSRX 100A
Maximum In-band Input Level: 0 dBm
Impedance: 50 ohm
Sensitivity (noise level): -160 dBm in 1 Hz BW
Required Power: One of either 120 v AC or 220 VAC, 50-60 Hz, 100 watts
FCC approvals to transmit in place. Radio power levels are similar to that of a CB radio. Detailed EM studies available upon request.
SCCOOS retains a NEPA categorical exclusion for this equipment. CEQA does not apply.
Scripps Institution of Oceanography
Installation of similar hardware at
Battery Humphries on Point Loma
Antenna location
Deployed: August 30, 2002
Scripps Institution of Oceanography
Example Long Range CODAR Deployment depicting
relative Transmit and Receive antenna locations
Nantucket Island, MA
Scripps Institution of Oceanography
Potential San Clemente
deployment locations
PEAK
Scripps Institution of Oceanography
Option 1: Vicinity of Stone Station
Stone Station for power
and enclosure
Northern view from Stone Station:
potential CODAR site
SPAWAR property
50 meters
Option 2: SPWAR Property
Northern view from Rigging area