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CODAR Currents Newsletter Spring 2010
The RiverSonde The RiverSonde

RiverSonde® Grants

CODAR offers at least two RiverSonde equipment loan grants for graduate studentsin 2010
Proposals due by 31 March.

It least two equipment loan and travel expense grants are available for year 2010 that include use of a RiverSonde unit.

CODAR Ocean Sensors, Ltd. is seeking proposals outlining novel applications of RiverSonde in river, lake, estuarine, harbor, or ocean environment. Novel applications could be (but not limited to) measurement of near-shore ocean rip currents or flows at river intersection with ocean or lake, integration of RiverSonde data with other data sets collected inside of a regional ocean observing system, and use of RiverSonde data to improve or validate coastal or river hydrodynamic models, etc. Motivated graduate students interested in hydrology, oceanography or other related subjects are encouraged to apply.

Award Highlights:

• Grantee has use of RiverSonde for up to 3 months.

• CODAR engineer will travel to assist with equipment installation and provide a training course to grantee and their associates at grantee’s institution or deployment site.

• $1,300 in travel funds also provided by CODAR for grantee to present their results at a scientific conference/ workshop pre-approved by CODAR (payment made to grantee upon abstract acceptance).

• Grants are limited to equipment use inside of the United States. Future grant programs may be offered for other regions.

Applications will be accepted 1 February- 31 March 2010. Review of proposals and awards will be conducted on a continuous basis throughout period, so early submissions are encouraged. All awards will be announced by or before end of April 2010.

Complete grant details are posted at CODAR company web site at news_01_1_2010.shtml


RiverSonde® Grants Available
CODAR is supporting education and research by offering equipment grants that include their latest cutting-edge technology.

A Peek Inside California’s
SeaSonde® Network

Romberg Tiburon Center Manages a uniquely diverse radar node in equally diverse settings

Giant Eddy Revealed Off
California Coast

One of the Pacific’s beauties is seen in the COCMP radar data.

On the Horizon:
Reducing Power Needs at
Seasonde Locations

Power requirement may be reduced by as much as 90% with breakthroughs in transmit amplifier efficiency and other design innovations.

Software News
A look inside SeaSonde Release 6

A look Back in Time-
The Birth of CODAR at NOAA

Learn about CODAR technology origins at NOAA.

CODAR Returns to Gibraltar
SeaSondes to be deployed for monitoring Gibraltar Strait.

Transmit & Receive With a
Single-mast Antenna System

CODAR-patented technology brings new excitement to HF radar network siting possibilities.

Upcoming Events

A Peek Inside California’s Radar Network
COCMP SF Bay - Gulf of Farralones Node Personnel shown (left to right): Toby Garfield, Chris Raleigh, Jim Pettigrew, Max Hubbard, Matt Gough

A Peek Inside California’s Radar Network
Figure showing a 25 hour average of surface currents in the Gulf of the Farallones and San Francisco Bay. Data are from the San Francisco node combined with data from the Bodega and Monterey nodes on 2010-01-25.

Point Bonita lighthouse and fog station
Point Bonita lighthouse and fog station.
A Peek Inside California’s Radar Network

The HF Radar team at San Francisco State University’s Romberg Tiburon Center face variety, beauty& sometimes danger all in a day’s work Contributed by Jim Pettigrew, SFSU RTC

hrough California voter-approved bond funding, the Coastal Ocean Currents Monitoring Program (COCMP) was established to measure coastal surface circulation along the whole California Coast. Initially started in 2005, COCMP is now an array of nearly 60 CODAR SeaSondes covering the whole coastal region from the Oregon border south to the Mexican border. In order to provide complete coverage, and also to offer higher resolution in areas of high potential impact from buoyant discharges in regions with high population, the network is designed as “nested” with standard and high resolution systems embedded within the broader Long-Range coverage area. The entire coast is mapped with an array of nine Long-Range (5 MHz) systems to provide 6 km resolution of surface currents from the shore out about 180 km. Between Bodega and Big Sur and in the Southern California Bight, arrays of standard range systems operating at 12 and 25 MHz provide 3 km and 1 km resolution of the currents within 80 km of shore. In San Francisco Bay-- an area that is quite dynamic and at high risk for environmental incidents--an array of four 42 MHz SeaSondes offers 0.4 km spatial resolution for the currents in the central portion of the Bay. This high-resolution portion of network provided important current information during the response effort to Cosco Busan oil spill of 2007.

The COCMP system is subdivided into eight “nodes” each of which is responsible for the operations and maintenance of the radars in its geographic region. Our Romberg Tiburon Center (RTC), part of San Francisco State University, operates the San Francisco Bay and Gulf of the Farallones node whose coverage extends from Point Reyes, south to Pillar Point and into San Francisco Bay. The RTC node consists of 10 SeaSonde units and is the only node to include instruments operating at all the basic SeaSonde frequencies: 4-6 MHz, 12-14 MHz, 24-27 MHz, and 40-44 MHz. Operations of the RTC node are under the leadership of Toby Garfield and managed by Jim Pettigrew, with assistance from Chris Raleigh, Matt Gough and Max Hubbard.

Six units are on Golden Gate National Recreational Area properties for which U.S. Park Service been a terrific partner. We also maintain sites on properties administered by the Air Force, the Coast Guard, and the cities of San Francisco, Sausalito and Montara.These radar locations are each quite interesting. One of our Long-Range SeaSondes resides at Pillar Point directly above Mavericks , the famed big-wave surf break, while a 12 MHz unit in Bolinas sits on the property of the historic Marconi ship-to-shore transmitter array which was built in the early 1900’s. Visiting these locations offers both beauty and a little bit of history.

Not all locations are created equal and some pose logistical and physical challenges: Our first radar set at the Romberg Tiburon Center facility was easy to install and is conveniently accessed by stepping directly outside our office doors. In contrast, our latest site, a 25MHz unit at the Point Bonita Lighthouse and Fog Station, took several years working through bureaucracy to receive land use approvals from the Coast Guard and visiting this site is not for the faint of heart.
After a long hike, then passing through a narrow tunnel with low clearance, to reach the antenna location one needs to suppress vertigo while walking on a swaying footbridge above a perilous chasm. The antenna is bolted to a ledge of pillow basalt high above surging waters and the blast of the fog horn requires ear plugs be worn at all times. The demonstration of bravery and the extra effort RTC staff make to operate at this location is justified as the radar has a 240-degree field of view and provides 1km resolution coverage of the treacherous waters of the San Francisco Bar and Golden Gate Channel..
Snapshots below highlight journey to SeaSonde location at Point Bonita Lighthouse.
All Images provided courtesy of Jim Pettigrew, SFSU Romberg Tiburon Center
Entrance to the Point Bonita tunnel Tunnel’s slippery, low-ceilinged passageway Corroded cables limit traffic to two persons at a time Footbridge to Pt. Bonita Lighthouse SFSU grad student Max Hubbard assembling radar antenna SeaSonde antenna sits about 15m above the water
Entrance to the Point Bonita tunnel Tunnel’s slippery, low-ceilinged passageway Corroded cables limit traffic to two persons at a time Footbridge to Pt. Bonita Lighthouse SFSU grad student Max Hubbard assembling radar antenna SeaSonde antenna sits about 15m above the water

Who Would’ve Known? Seasonally Recurring Giant Eddy
Seen Off California

Remember the fascinating double-gyre structure Jeff Paduan discovered off Monterey Bay 15 years ago from SeaSonde current maps? A bit over a year ago, Greg Crawford and Shannon Stone (of Humboldt State); Chris Halle and John Largier (of Bodega Marine Laboratory) found a giant eddy lurking off Mendocino with their recently installed Long-Range SeaSonde at Shelter Cove, combined with the unit at Pt. Arena. This eddy, they determined, was produced by the NNW winds that drive upwelling off the coast during August - October every year. It is a regular visitor during this period.

As the resulting cold-water jet, up to 2 knots near the coast, flows to the South, it becomes an anticyclonic eddy that has a mammoth diameter up to 170 km. Entraining warmer water in its center, shown by the lighter color in these consecutive figures the colder coastal waters are swept offshore around its Southern edge. Although the example here was seen in 2008, we can attest that this same huge eddy was the most prominent eye-catching feature seen in the zoomed-out West-Coast HFR Net data during the same period in 2009.

These long-range radars are part of the COCMP network that now comprises 60 SeaSondes covering the State of California. Many of the radars are shorter-range, higher-resolution units centered around populated areas and bays. But the long-range systems span the shelf, and when combined with satellite observations like temperature, reveal fascinating dynamics that impact biological fisheries productivity we depend on along our West Coast. As the upwelling winds die (wind shown as the red arrow), this fascinating feature disappears, and a relaxation phase with weak Northerly flows dominates near the coast the remainder of the year.

The authors of the AGU presentation in which this discovery was displayed used animations they called “particle backtracking” from the SeaSonde current maps to determine the origins of the water from a grid of points within the eddy. This type of analysis reveals the surface water pathways and length of time it takes floating particles to traverse the region. The figures below are from that presentation.
Who Would’ve Known? Seasonally Recurring Giant EddySeen Off California

On the Horizon: Reducing Power Consumption at SeaSonde Locations
Why does the CODAR set industry records only to break them shortly after? Because innovation is the key to expanding utility! CODAR engineers are working to lower the entire radar site power requirement by as much as 40-90% of present needs. In this latest development effort CODAR engineers are reducing the power requirement to an average of 150 watts for the SeaSonde radar AND cooling system. This ultra-low power system is ideally suited for remote areas where renewable power sources or operation from generators is only viable option. Read on to learn about this exciting work...
Development Impetus
When calculating the total power required at any radar site, you need to factor in the consumption of the radar plus that of any associated infrastructure at that location. Temperature and humidity control for the electronics enclosure is the potential biggest power draw at the radar site. In mild climates, keeping the electronics within optimal temperature ranges can often be achieved with a simple heat exchange fan that draws only 25 watts power. In contrast, cooling the electronics in warmer climates or stagnant air becomes more complicated; simple low-power heat exchangers are not adequate for the task and in those cases use of a closed-loop air conditioning system is required. Though power for a SeaSonde radar is only 350-450 watts, air conditioners can sometimes require up to 1.5 kilowatts of power-- over 4 times that of the SeaSonde itself. This poses a problem when power must be derived solely from renewable sources (e.g. solar or wind), presenting logistical challenge and high cost.
Prototype Class-E transmit amplifier
Prototype Class-E transmit amplifier shown here.
Reducing Power With New Design Features

Highly Efficient Transmit Amplifier
The conventional SeaSonde transmit amplifier efficiency is 30%, which is standard for Class-AB amplifiers designed for use at HF. CODAR engineers have developed and will be utilizing a breakthrough design Class-E transmit amplifier having an TX efficiency over 80%. This not only reduces the amount of required power input to transmit amplifier but also the amount of heat generated that would otherwise need dissipation.


Electronics Packaging & Built-In Cooling System

A key consideration to maximizing system efficiency is heat management. The entire electronics layout is being revamped to optimize heat dissipation inside the system. The transmit and receive electronics are stripped from the traditional two 19” electronics chassis and assembled together into one small package, roughly 0.75m height x 0.5m width x 0.5m depth. This sealed case is weather resistant and suitable for both indoor/ outdoor use. A cooling system is built into casing with a temperature sensor inside electronics allowing for intelligent auto on/off.

System Requirement
With an average draw of 150 watts, the power requirement will vary throughoutnormal operations from 130 watts - 200 watts, based on the local temperatures(and hence internal air cooling requirement). Any power generation system shouldbe engineered to at least 150 watts under any expected local weather conditions.

Consult CODAR for additional information.

Wind turbine supplying power to a SeaSonde in Alaska. Image courtesy of RachelPotter, University of Alaska, Fairbanks

Software News:
SeaSonde Release 6 Offers
Exciting Features & Convenience

As of September 2009, CODAR released our most user-friendly radial site software yet. Release 6 comes with a number of improvements to make set up and maintenance of your radar sites easier while also providing more robust operation. If you are the squeamish type when it comes to new software releases, fret not. Months of in-house and beta testing on operational systems have made our latest update one that is very stable and ready for prime time.

The feature we are sure will make every technician’s life easier is our new Radial Web Interface. We’ve utilized some of the latest technologies built into Mac OS X 10.6 Snow Leopard, including Ruby On Rails, to create a password-protected interface to the radial site data and diagnostics that is accessible via any standardscompliant web browser. No special app is necessary. You can log on from a friend’s computer or even your iPhone or Blackberry. With built-in email alerts, you can be notified while on the go and diagnose most issues directly from your mobile phone’s browser. With the one-click download of a system report that covers computer, hardware and data quality checks, it’s never been so fast and easy to get a snapshot of radar site health.


CODAR support engineer Hardik
Parikh enjoys a latte at a sunny
California cafe while accessing and
checking status of a SeaSonde
operating in eastern Canada through
his iPhone.
SeaSonde Radial Site BML1 - screen shot
SeaSonde Radial Site BML1 - screen shot
While we’re sure you’ll enjoy using the Radial Web Interface, we’ve also made big changes to our on-board applications that technicians will appreciate whether novice or expert. Are you tired of siting the antenna’s black arrow bearing, correcting for magnetic declination and then adding 45° to get the loop 1 bearing? If so (or if the last sentence just completely confused you), don’t worry, our improved Radial Setup App means you only have to remember one number and it takes care of the rest. Only the essential information is required and a new layout makes it easier to remember what is important. SeaDisplay and SeaDisplay Setup are also much easier to use. Easier navigation control has been added for setting up site maps and oneclick buttons on the toolbar are now available to perform common tasks like making radial distribution plots.

Release 6 is also compatible with our latest Multi-Static Data Processing softwarepackage. Do you have radars in your network that are synchronized on the samefrequency using our patented SHARE technology but are not producing ellipticalvectors? If so, then you’re letting your data go to waste! To find out if Multi-Staticsoftware is right for your network, contact your favorite CODAR representative.You can see results of our most recent elliptical validation study in the latestissue of Remote Sensing: Lipa, B., C. Whelan, B. Rector, B. Nyden, HF radar bistatic measurementof surface current velocities: drifter comparisons and radar consistency checks,Remote Sens., vol. 1, pp. 1190-1211. 2009

Not quite ready to process your Multi-Static signals for currents? You can stillutilize SHARE with our Multi-Static Source Monitoring feature. Whether or notyou have the Multi-Static software package for currents installed, this allowsyou to monitor the transmit signal from other sites in your SeaSonde networkthat are synchronized using SHARE. This monitoring feature that comes includedwith Release 6 allows you to track any changes to antenna pattern characteristicsand log them over time – an important tool in QA/QC of your data.

There are many more under-the-hood changes in Release 6 that make SeaSonde radarsite operation more robust and user-friendly. To see if your computer and operatingsystem are compatible with Release 6 or to download the installer, please visitour support website at or contact a CODAR representativetoday.

    A Look Back In Time... The Birth of CODAR at NOAA

SeaSonde Evolution
he first HF radar to demonstrate and validate current and wave measurement capability was built between 1969-1973 in a program led by DARPA and NOAA, in cooperation with Scripps Institution of Oceanography and Stanford University. Designed by Donald Barrick at NOAA Environmental Research Laboratories (ERL), the radar with its conventional 500-meter long phased-array antenna was bulky and inconvenient for deployment, but proved the point that HF radar is a viable tool for measurement of ocean current and wave parameters.

After the initial success, NOAA's ERL commissioned Dr. Barrick in 1972 to develop a practical replacement for the large and expensive phased array antenna design. The technology resulting from this NOAA program was called CODAR, an acronym standing for Coastal Ocean Dynamics Applications Radar.

In 1977 the prestigious journal Science published an article on the demonstrated CODAR success. Shortly after, in 1978 the NOAA team that developed CODAR was awarded the U.S. Department of Commerce Gold Medal Award. Various patents relating to the technology were granted within the NOAA group starting in 1979.

In the early 1980s, the core team that invented the original CODAR was encouraged by NOAA to move into private industry, to continue the technology evolution and provide a commercial source for institutions to acquire HF radar equipment. That company became CODAR Ocean Sensors, Ltd. The technology has evolved from original CODAR radar and is now the SeaSonde®. It remains the only commercially available HF radar system that is based on the groundbreaking compact HF radar concept developed and patented inside NOAA, while all other HF radars still utilize the phased array approach that was abandoned back in the 1970s. As of 2010, the SeaSonde represents over 85% of all HF radars ever built and used for ocean current and wave measurements, with systems used in 22 countries.

Photos illustrate the current mapping HF radar antenna evolution. Starting with image #1: 500-m long phased array radar at San Clemente Island, circa 1972. Smaller inset image shows the trailers used to house the radar electronics and computer system. Image #2: the first NOAA-built CODAR antenna system consisting of a square monopole receive array with direction-finding closed-form solutions for bearing. Smaller inset image shows the electronics and DEC PDP-11/23 computer and tape drives used for near-real-time processing and archival. Image #3: The first crossed-loop CODAR antenna, built of copper. Image #4: a later version of crossed-loop CODAR antenna, built of PVC. Image #5: Successor to CODAR, the SeaSonde. Image #6: Latest SeaSonde antenna system with all transmit and receive elements colocated atop a single mast. The unit shown is located on Scripps Pier in La Jolla, California. Image #7 shows latest SeaSonde electronics system, consisting of a small but powerful mini-processor and two 19” electronics chassis.
SeaSonde Evolution SeaSonde Evolution

CODAR Returns to Gibraltar
In January 2010 the Regional Government of Andalucia has confirmed funding to a “Proyecto de Excelencia Investigadora” program that includes a 1-year temporary deployment of two 25 MHz SeaSondes in the Gibraltar Strait. This new program is under the scientific leadership of Cadiz University, with the operational coordination of Puertos del Estado and with the participation of Sasemar, Instituto Hidrográfico de la Marina, Instituto Español de Oceanografía, the Harbours of Algeciras and Ceuta, Malaga University, Abdelmalek Essaâdi University of Tanger, Naval Postgraduate School Monterey, Empresa de Gestión Medioambiental de Andalucía, The Spanish and Moroccan Society for the Study of Transport Communication Across Gibraltar Strait, Natural Park of the Strait, and the engineering company QUALITAS Remos. The official project title translates roughly to “Current monitoring by means of coastal HF Radars as a core element of the Operational Oceanography System of the Gibraltar Strait”. Installation of the radars will happen in Cape Carnero and Ceuta Harbour inside 2010.

This could very loosely be described a “re-deployment”, as 28 years ago CODAR units (predecessors of the SeaSonde) operated in this Northwest Alboran Sea area. Named “Donde Va”, the 1982 field campaign objective was to study gyres created by the jet inflowing through Gibraltar from the Atlantic. This was a multinational program that included joint tests between National Oceanic and Atmospheric Administration (NOAA) Wave Propagation Lab and Naval Research Lab (NRL) in Stennis, Mississippi. NRL group focused on satellite and aircraft remote sensing with the CODAR HF radar work carried out by NOAA.

For further reading on the 1982 deployment and results, we recommend: Janopaul, M. M., Frisch, A. S., CODAR measurements of surface currents in the northwest Alboran Sea during the Donde Va experiment, Annales de Geophysique, vol. 2, no. 4, pp. 443-448. 1984
Carnero lighthouse at Cape Carnero
Carnero lighthouse at Cape Carnero.

View from the Ceuta Harbour breakwater
View from the Ceuta Harbour breakwater.

Transmit & Receive With a Single-Mast Antenna System
For over a decade SeaSondes operating between 24-50 MHz frequency band have an antenna system that co-locates both transmit and receive antenna elements atop a single mast. Recently this capability to operate with a single-mast antenna system has been expanded to include lower frequency bands down to 12 MHz.

Though a traditional two-mast antenna system – one for transmit antenna and one for the receive antenna – is already extremely compact by conventional HF radar standards, a single mast antenna system represents a critical practical convenience when installing in congested urban areas, on oil platforms or atop other manmade structures.

The first 12 MHz combined antenna systems were purchased by Scripps Institution of Oceanography (SIO) for use on oil platforms in the Gulf of Mexico. Shown in photo are CODAR company President Don Barrick and Tom Cook of SIO with the first 12 MHz combined antenna. This unit was delivered to SIO in 2008.
SIO’s Tom Cook (left) with CODAR company President Don Barrickand the first 12 MHz combined antenna.
SIO’s Tom Cook (left) with CODAR company President Don Barrick
and the first 12 MHz combined antenna.



Ocean Sciences
22-26 February 2010 Portland, Oregon

Oceanology International
9-11 March London, England

SeaSonde Training Course
3-6 May 2010 Northern California

2010 The Meeting of the Americas
8-13 August 2010 Foz do Iguacu, Brazil
We recommend participation in the OS02 session: Application of HF Radar Networks to Ocean Forecasts.

Links to these conference official web sites can be found in Upcoming Events Section of CODAR home page

Crissy Field SeaSonde
Important Announcement on Not-to-Miss Meeting this Fall:

High-Frequency Radar Workshop 2010 (HFRW 2010)
Theme: Global Forum on HF Radar Applications & Coordination

Workshop Purpose and Objectives
High-Frequency (HF) radar systems and networks are employed in a variety of operational, societal and research applications. SeaSonde HF radars are now used widely for such purposes and represent over 85% of all HF radars used for ocean monitoring. The theme of the High-Frequency Radar Workshop (HFRW 2010) is “Global Forum on HF Radar Applications & Coordination”. The workshop program addresses the application of data from these HF radar systems and networks, with focus on several key application areas, and also addresses some critical issues with designing, building and sustaining an HF radar network to serve the needs of a variety of users. The workshop objective is to bring greater understanding of these topics to those agencies or key persons who are or will be responsible for funding, designing and implementing a multi-application HF radar network, and to those entities or individuals who may benefit from the data products.

The workshop is organized so that leaders in these fields will select subjects and speakers within topic-oriented sections. These sections would be conducted as talks followed by panel discussions, among the panel members and the other participants. Hence a primary goal is to introduce to, and promote among new and existing users, the latest important applications of this vibrant, growing technology.

When: Fall 2010. Exact dates to be announced in Spring 2010. Workshop will occur across a 4 day period.
Where: United States. Specific location to be announced in Spring 2010. Contact: If you are interested in participating in the upcoming HFRW and wish to be added to conference mailing list or have questions on this subject, please contact the HFRW meeting administrator Allison Mendes at phone +1 (408) 773-8240 x23, or send email to

Details on HFRW will be posted on CODAR company web site at
If you have any questions, please email us: CODAR Ocean Sensors logo

1914 Plymouth Street
Mountain View, CA 94043 USA
Phone: +1 (408) 773-8240
Fax: +1 (408) 773-0514


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