A note on the potential transport of scalars and organisms by surface waves

Abstract

Wave-induced transport that is not directly reflected in Eulerian current measurements, an effect known as Stokes drift, may play a significant role in the transport of organisms and solutes in the nearshore environment. Two sets of field observations are presented that illustrate the potential importance of wave-induced transport. Velocities measured near Santa Barbara, California, are used to show that the theoretical Stokes drift can be stronger than measured Eulerian currents. Dye plume measurements made at Duck, North Carolina, in both wavy and nonwavy conditions indicate that wave-induced scalar transport can be significant. To demonstrate the generality of these results, we present calculations of the Stokes drift for several depths and as functions of wave amplitude and period. Given that cross-shore velocities typical of the nearshore coastal ocean are generally comparable to or smaller than these computed values of the Stokes drift, we conclude that observations and predictions of nearshore transport should include explicit consideration of wave-induced transport.