OREGON STATE UNIVERSITY

OSU grant to aid understanding of coastal waters

11/16/1998

CORVALLIS - A $3.76 million Oregon State University research project just launched off the Oregon coast may help Northwest fishermen increase their chances for a sustainable catch, sailors improve their navigation and scientists better understand the coastal ocean's influence on salmon and other sea creatures.

"It also could help the Coast Guard with search and rescue operations or in tracking pollutants," said Jack Barth, an associate professor in OSU's College of Oceanic and Atmospheric Sciences.

Barth and John Allen, OSU professor of oceanic and atmospheric sciences, are the principal investigators involved in the project called "Prediction of Wind-Driven Coastal Circulation." The study focuses on winds and how they affect ocean flows along the continental shelf off the Oregon coast.

The National Oceanographic Partnership Program, comprised of more than a dozen national agencies including the U.S. Navy and the National Science Foundation, is providing $3 million for the two-year project. Additional funding is being provided by the OSU College of Oceanic and Atmospheric Sciences, CODAR Ocean Sensors of Los Altos, Calif., Ocean Imaging of Solana Beach, Calif., the National Oceanic and Atmospheric Administration and the National Marine Fisheries Service.

The researchers will use computer models that, together with other data, predict coastal water movement and the location of ocean temperature fronts. They can use that information, they say, to improve their tracking of anything from river sediment to oil spills, and provide valuable information for studies of the coastal marine ecosystem.

Barth said that along Oregon, the continental shelf ranges in width from 18 to 37 miles, sloping gently down from the beaches to a depth of about 650 feet before it "breaks." There the continental shelf quickly becomes the continental slope, dropping down to the two mile-deep oceanic abyss.

In general, Allen said, the large-scale aspects of coastal ocean circulation are understood. During the summer, the air over land is generally warmer than over water, setting up a pressure force that creates strong winds to the south. This air movement helps push near-surface water offshore and toward the equator and allows colder, nutrient-rich water to well up from the deep ocean.

This increase in nutrients near the surface then leads to enhanced biological productivity. And, as this cold, upwelled water meets warm air, conditions become ripe for fog, Barth said.

During the winter, winds that are predominantly from the south push currents northward and toward the coast, causing coastal sea levels to rise and eventually pushing surface water down.

But it's the small-scale circulation features over the continental shelves that are generally poorly understood, the researchers say. Those features can have a great influence on mixing of ocean layers and transport of heat, momentum, nutrients, animals and just about anything else found in the water.

"Winds can create persistent currents stronger than the fluctuating tides," Allen said, "with speeds typically about 50 centimeters per second (1.2 mph)."

For the next two years, Allen and Barth, along with 16 other OSU, federal and private researchers, will combine modeling, data assimilation and coastal observations in an effort to develop forecast systems for the wind-driven variations.

While the scientists will use land-based radar, satellite images, anchored buoys and cruise data to collect information on wind and ocean flow, the radar data will be the pillar of the study, Allen said.

"The radar is a crucial part of this study," Allen said. "About a year ago, OSU took delivery of it's Coastal Radar System." The system, under the direction of OSU associate professor Michael Kosro, provides hourly maps of surface currents over Oregon's continental shelf near Newport. Combining those radar current measurements with the coastal ocean circulation model - in the same manner that weather forecast models incorporate atmospheric observations - is a major goal of the project.

Next year, using the College of Oceanic and Atmospheric Sciences' research vessel, the Wecoma, the OSU scientists are planning a three-week intensive sampling of temperature and salinity, current speed and direction, turbulent mixing and other ocean properties off the coast near Newport.

The National Oceanographic Partnership Program coordinates oceanographic research by identifying and funding partnerships among federal agencies, academia, industry and others. Using a merit-based competitive selection process, this year NOPP funded partnership projects from researchers from 61 different organizations in 17 states. The OSU project is one of only four projects to address modeling and data assimilation, and one of just two located on the West Coast, Barth said.