A New Way to See the Ocean
Growing up, Warren Wood conceded he would one day become a scientist like his father Warren Wood, a hydrologist and professor at Michigan State University. No way, though, would the son follow his dad’s exact footsteps and become an earth scientist. There began what Wood calls a “strange and circuitous route” to his job as a geophysicist at the Naval Research Laboratory (NRL) at Stennis Space Center in Mississippi.
As an undergraduate at the University of Michigan, Wood discovered the joys of classical physics. “I liked the idea that you could predict natural phenomena with mathematical models, and I found things like gravity, electromagnetism, and kinematics fun and intuitive.” As a physics major, he had to take upper-level courses in particle and solid state physics, which did not have the same appeal. “After I graduated, I didn’t want to do particle or solid state physics, but that’s what most physicists were doing in those days,” he says.
What to do with an undergraduate physics degree? “I wandered around,” Wood says. “I went to Austin, Texas, on a whim in the middle of summer after graduation with no plan whatsoever. I sat in on graduate-level physics classes at the University of Texas and still wasn’t interested, so I found a job driving a forklift and moving rocks around.” The job was at the Texas Bureau of Economic Geology’s core laboratory — “a giant warehouse filled with rocks where geologists deposit sediment or rock samples and interesting rock formations,” Wood explains.
While laying out cores for the geologists, Wood would chat with them. He soon discovered that geologists use classical physics. What’s more, high-paying jobs were plentiful in the petroleum industry in the mid-1980s. “I realized I could do the science I enjoy and also make real money,” he recalls. He enrolled at the University of Texas and earned his master’s degree in geophysics in 1989. By then, though, oil prices were dropping sharply and jobs were disappearing. So Wood began working on his Ph.D. By the time he earned his doctorate in 1993, he had married and his wife was expecting their second child. More than “real money” he needed a “real job.” By chance, Wood’s advisor ran into a friend from NRL who mentioned that he needed a geophysicist who could do seismic wave form inversion. With that, Wood took his first “real job” and has been at NRL ever since.
Today, Wood leads a research team in the emerging area of seismic oceanography. “We noticed you can see wisps of reflection in the water column that indicate water is layered,” says Wood. But, he adds, “This was nothing new to oceanographers,” who were measuring changes in water density using conductivity-temperature-depth and other tools. One of Wood’s colleagues, Steve Holbrook, persisted in arguing that seismic systems designed to image sub-seafloor geologic structures were providing information about water layers in the ocean that oceanographers were missing. In short, says Wood, “Seismic oceanography represented a new way of observing ocean phenomena.”
Since then, Wood, together with NRL oceanographer Jeff Book and their research team, has made significant strides in the field of seismic oceanography, opening up “a new window on small-scale processes and mixing of the coastal and deep ocean.” By measuring the relationship between oceanic temperature contrasts and acoustic reflectivity, they are generating quantitative measurements of vertical temperature change throughout the water column at vertical and lateral resolutions several orders of magnitude finer than traditional methods. In a recent field exercise in the Adriatic Sea, NRL researchers and several international collaborators acquired both seismic and high-resolution oceanographic data including, for the first time, seismic measurements in shallow water.
“Essentially we are developing a new tool to make oceanographic models more accurate. Because the ocean is the fleet’s primary operating environment, the Navy has a huge interest in understanding ocean processes, such as currents, wave heights, temperatures, and so forth, particularly in shallow water,” Wood says. He and his colleagues believe that seismic oceanography will someday have other applications too, such as potentially tracking an oil spill through ocean layers — like the BP oil spill in the Gulf of Mexico. For now, there is still research to be done and signal processing algorithms to be written before seismic oceanography is incorporated into standard oceanographic practice.
Seventeen years after starting at NRL, Wood and his wife now have three boys, one of whom is a freshman in college. Whether any of them will follow their father and grandfather into science remains to be seen. “I tell them to follow their passion because what they love to do is what they will do best,” says Wood.
In his spare time, Wood enjoys peering at another type of liquid. He makes his own beer, an avocation in which he finds a bit of mysticism. “When you start putting the ingredients together, you never know exactly how it will turn out,” he says. “It is an interesting reminder that the world is not always under our control.”