Because they frequently mark the boundaries of currents, their position can be used to model the interaction of different oceanic current systems. Obviously, biological oceanographers study them because they are areas of high biological activity, from microscopic phytoplankton to large fish like marlin or bluefin tuna. Even loggerhead turtles have been shown to frequent the area of convergence zones in the Pacific Ocean. A variety of remote sensing technologies can be used to view convergence zones, due to the abrupt changes in water mass characterisitics that define them. SAR is extremely sensitive to very small variations in the surface of the ocean, so it can actually be used to view the wakes of ships.
Convergence zones show up clearly due to several factors.
One factor is that a height difference of a few centimeters actually marks the boundary of the warm water and the cold water, so that the zone can actually be marked by waves and surface turbulence. Thus, convergence zones show up as smooth areas, or slicks, due to the reduced wave action caused by the presence of surfactants. Note near the center of the image where the bright and dark areas are roughly parallel, delineating the convergence zone. Observation of a smooth lake surface during a rainstorm will also show the development of smooth linear areas parallel to rougher areas. These features are due to the slight differences in temperature between rain water and lake water cause the formation of upwelling and downwelling areas.