The temporal, vertical, and alongshore variation in inner‐shelf temperature, T, across subtidal (ST), diurnal (DU), and semidiurnal (SD) bands on coastlines with headlands is not understood. Inner‐shelf T was observed with 20 moorings in 9‐ to 16‐m depth with high vertical density during Fall 2017 along 50 km of central California coastline with headlands. The ST‐first empirical orthogonal function is largely barotropic. ST warm water events are associated with northward‐propagating buoyant plumes and onshore advection of offshore water, with headland effects, particularly for stronger events. Previous plume arrival criteria are northward propagation biased. The DU vertical structure was mixed barotropic and linear baroclinic, without surface extrema. Inner‐shelf DU‐band temperature variability was always evident, largest north of and weakest south of two headlands. The DU‐T envelope was not modulated by ST stratification and was not linked to the modeled DU‐wind envelope. North of one headland, the alongshore first complex empirical orthogonal function of DU temperature has a previously unobserved southward 2‐m/s phase propagation, even though DU frequency is subcritical, that is, not wind forced. A frictional subcritical wave mechanism is proposed for the DU propagation. The SD‐T vertical structure varies alongshore, suggesting at different locations linear internal waves and nonlinear cold bores. SD‐T variability was incoherent with barotropic tides and decorrelates alongshore in 7.5 km, contrasting with a few kilometers offshore. The SD depth‐averaged energy varied strongly alongshore particularly north and south of the headlands, and stronger and weaker SD energy was linked to nonlinear and linear baroclinic vertical structures, respectively, which are headland influenced.

The inner shelf, the transition zone between the surf zone and the mid shelf, is a dynamically complex region with the evolution of circulation and stratification driven by multiple physical processes. Cross-shelf exchange through the inner shelf has important implications for coastal water quality, ecological connectivity, and lateral movement of sediment and heat. The Inner-Shelf Dynamics Experiment (ISDE) was an intensive, coordinated, multi-institution field experiment from Sep.-Oct. 2017, conducted from the mid shelf, through the inner shelf and into the surf zone near Point Sal, CA. Satellite, airborne, shore- and ship-based remote sensing, in-water moorings and ship-based sampling, and numerical ocean circulation models forced by winds, waves and tides were used to investigate the dynamics governing the circulation and transport in the inner shelf and the role of coastline variability on regional circulation dynamics. Here, the following physical processes are highlighted: internal wave dynamics from the mid shelf to the inner shelf; flow separation and eddy shedding off Point Sal; offshore ejection of surfzone waters from rip currents; and wind-driven subtidal circulation dynamics. The extensive dataset from ISDE allows for unprecedented investigations into the role of physical processes in creating spatial heterogeneity, and nonlinear interactions between various inner-shelf physical processes. Overall, the highly spatially and temporally resolved oceanographic measurements and numerical simulations of ISDE provide a central framework for studies exploring this complex and fascinating region of the ocean.

Steady and tidal (oscillating) flows past topographic features such as headlands and islands lead to wake development and eddy shedding (e.g.,