BENEATH THE SURFACE
LSU professor studies the behavior of water in coastal regions

On a planet where the majority of the surface area is covered by water, the study of the oceans — the largest source of water on the planet — can be a daunting task. Though many people may not think about the changes that occur beneath the surface on a daily basis, those changes can have strong impacts on our lives. LSU assistant professor of oceanography and coastal sciences Chunyan Li and his research partners are searching for better ways to predict the behavior of the fine structures and fronts of oceans and coastal regions.

The term “fine structures” refers to water properties like the velocity, temperature, and density of the spirals and eddies found in water systems. Fronts are areas in a body of water where sharp changes in these water properties occur. For example, water temperature usually changes by one degree Celsius over tens of kilometers, but a more drastic change occurs along the edge of the Gulf Stream – a powerful Atlantic current that influences the climate of the Eastern United States and Western Europe. Here, the temperature can change two degrees per kilometer at times.

Studying fine structures and fronts in an oceanic setting is costly, so researchers often use mathematical models to help them predict water behavior. With a grant from the Office of Naval Research totaling $300,000 over the course of three years, Li and his coworkers are using a combination of high-resolution satellite observations and field observations of the Taiwan Strait — a 130-to-360-kilometer-wide strait between the coast of mainland China and Taiwan — to determine what drives the behavior of fine structures. With a better understanding of what motivates these behaviors, researchers can improve their mathematical models. Data gathered in the field and from satellites can also be incorporated into the mathematical models, enabling scientists to make better predictions.

Understanding fine structures and fronts can be beneficial in many ways including several that carry particular importance for coastal areas like Louisiana. These studies can aid the management of marine resources, as fish tend to be found in large quantities around fronts. They also tell us more about land-ocean interactions, carbon cycles, and the transport of pollutants and other materials in the water.

“Louisiana’s coast has lots of interesting fine structures and fronts, in part because of the meeting of and interaction between river and ocean waters which have very different sets of properties. Studying these fine structures helps us to understand the complex coastal dynamics of the water and its circulation and the transport of sediments and freshwater,” says Li.

In addition to his studies in the Taiwan Strait, Li and other researchers are using funding from the National Science Foundation to study the impact of hurricanes Katrina and Rita on the water transport processes within Lake Pontchartrain. Li also conducts research in the East China Sea, Alaska, and along the east coast of the United States, near the Gulf Stream.

ON THE WEB:
LSU Department of Oceanography and Coastal Sciences
LSU Coastal Studies Institute

from Summer 2006 Issue