Written By Dan Suthers based on explanations by Scott Ferguson,
June Firing, Kyle Hogrefe, and Danny Merritt. Physical
Oceanography studies the movement of ocean water (ranging from
small scale oscillations to basin-wide flows) and the physical
and chemical characteristics of that water (e.g., temperature
and salinity). Most research on currents and water
characteristics has focused on large scale patterns, such as
gyres that flow around ocean basins . Water of different
densities does not mix easily. Density depends on temperature
and salinity. Therefore, if you measure the temperature and
salinity of water at different depths you can track the same
body of water as it moves around an ocean basin (e.g., the North
Pacific) and even around the globe. In this research,
measurements are often taken on a large scale. For example,
during a transect a ship might make measurements of water
temperature and salinity at different depths, but do so only at
every degree of longitude or latitude: about every 60 miles. One