SALMON project tracks currents in Cook Inlet

Posted: Tuesday, March 04, 2003

A project designed to measure surface currents on Cook Inlet using radar was introduced to directors of the Cook Inlet Regional Citizens Advisory Council in Kenai on Friday.

The SALMON Project, an acronym for Sea-Air-Land Modeling and Observing Network, was explained by David Musgrave, an associate professor from the University of Alaska Fairbanks. The project maps surface currents by way of land-based radar, said Musgrave, who told the group that two radio antenna sites on the east side of Cook Inlet currently are active.

Each site consists of two antennae -- one to transmit radio waves and one to receive. Transmitted radio waves scatter off the waves on the surface of the ocean, and some are recorded by the receiving antenna.

The radio waves are then used to compute currents moving toward or away from the radar sites.

"One site only gives surface velocities (of ocean waves) in the line of sight," Musgrave said.

"With two sites, we can get two-dimensional velocities by vectoring data from the two sites."

The School of Fisheries and Ocean Sciences associate professor demonstrated an online Web site on which people can watch real-time information from the radar sites mapping currents from ebb tides to slack tides to high tides.

"We've been collecting data from these sites since Dec. 1," Musgrave said.

He described the SALMON Project as part of a larger Coastal Alaska Observing System he is working toward implementing for the coastal ocean in Alaska.

During a computer-based visual presentation to CIRCAC, Musgrave listed several uses for the information being collected, including facilitating safe and efficient marine operations, detecting and forecasting oceanographic aspects that affect climate, managing marine resources, preserving and restoring healthy marine ecosystems, lessening the effects of natural hazards and ensuring public health.

As an example of the usefulness of the CAOS observing system, Musgrave said it can be used to show how water near Seward ends up in Cook Inlet 15 days later.

"We saw this during the oil spill," he said, referring to studies done after the 1989 Exxon Valdez oil spill in Prince William Sound.

He said the U.S. Navy has shown interest in the capabilities of CAOS for national security and said it is effective for use in navigation, to predict such events as tsunamis and El Nino and to measure physical salinity of coastal waters and fish abundance.

"Alaska State Troopers are anxious to get this in place for search and rescue," Musgrave said. "We can tell them exactly where they are and where currents are taking them. Real-time observation (of surface currents) through CODAR allows this."

Unlike other oceanographic systems that are driven by the science community, Musgrave said this ocean-observing system will be driven by users.

"Rather than have scientists with a specific area of interest decide what's in the system, users will decide," he said.

The first radar site in place on Cook Inlet is just south of East Forelands and the second is near the southern end of Kalifornsky Beach Road.

A second set of instruments is planned for the entrance to Kachemak Bay -- one at a field station in Homer and one off Barabara Point.

Asked by one of the CIRCAC members in attendance if CAOS isn't duplicating data already being gathered by others, Musgrave said, "The whole point of CAOS is to get cooperation among agencies."

He described CAOS as a partnership between industry, such as fisheries, shipping and oil services; government, including the Alaska Department of Fish and Game and U.S. Fish and Wildlife; nonprofits, including the Prince William Sound Science Center and the Barrow Arctic Science Center; and academia, including the University of Alaska, Rutgers and the University of Washington.

He said more information about the SALMON Project is available online at and the site also includes links to information about CODAR and CAOS.

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