THERMOCLINE PENETRATION BY BUOYANT PLUMES

Plumes of buoyant fluid rise in a stratified environment until their b uoyancy with respect to the environment reverses, they become heavier than their surroundings and gravitational forces bring them to a halt. Obstacles to turbulent plume rise, occur in the form of external stra tification and two-component mixing, which changes the buoyancy of the plume. Volcanic eruptions introduce large amounts of heat to the wate r column, and the question arises as to whether or not such eruptions can drive plumes up to the sea surface, and create a significant sea s urface temperature anomaly. A turbulent plume model is used to estimat e the magnitude of an eruption which might be capable of driving a plu me across the ocean's thermocline, which poses a substantial barrier t o vertical motion-more so, for instance, than the tropopause with resp ect to atmospheric plumes. The confining effect of Earth's rotation he lps to maintain stronger anomalies in the horizontal spreading phase o f the motion at the sea surface. Plumes which cannot attain the surfac e may also have substantial temperature and salinity anomalies if thes e quantities vary in the the source or water column through which the plume rises and entrains water.