Cross-shore transport of larvae, pollutants, and sediment between the
surf zone and the inner shelf is important for coastal water quality and
ecosystems. Rip currents are known to be a dominant pathway for
exchange, but the effects of horizontal temperature and salinity
gradients are not well understood. Airborne visible and infrared imagery
performed on the California coast show warm and cool plumes driven by
rip currents in the surf zone and extending onto the shelf, with
temperature differences of approximately 1$^\circ$C.
The airborne imagery and modeled temperatures and tracers indicate that
warm plumes exhibit more lateral spreading and transport material in a
buoyant near-surface layer, whereas cool plumes move offshore in a
subsurface layer. The average cross-shore extent of warm plumes at the
surface is approximately one surfzone width larger than for cool plumes.
Future work may explore the sensitivity of nearshore plumes to density
patterns, wave forcing, and bathymetry.