Freismuth, T. M., D. Cai, J. H. MacMahan, K. A. Haas, J. A. Colosi, S. Suanda, N.
Kumar, E. Di Lorenzo, A. Miller and C. A. Edwards, 2017:
Upwelling response to subtidal, alongshore inner shelf flow around a small-scale coastline
Journal of Physical Oceanography, sub judice.
The 43-day Pt. Sal Inner Shelf Experiment aimed at measuring temporal and spatial variability of
currents and water temperature near the Pt. Sal headland on the central California coast during
the summer of 2015. Subtidal water temperature and currents were obtained with 32 thermistor
strings and 6 acoustic Doppler current profilers in 5 to 50 m water depth covering 4 km
alongshore and 6 km cross-shore. A key feature of this area is an O(300 m) coastal promontory
north of Pt. Sal named Mussel Pt. The flow was primarily wind-driven with periods of
upwelling favorable winds with a cross-shore component. Alongshore temperature anomalies
show that a temperature gradient (0.33C/km) is set up with warmer water to the north of
Mussel Pt. and colder water to the south of Pt. Sal during upwelling. Momentum balances from
numerical simulations show that Mussel Pt. creates negative pressure gradients that drive the
onshore flow. Additionally, cross-shelf transport to the edge of the surf zone was driven by an
onshore component of the wind stress, flow separation around Mussel Pt., and supported by a
weakly stratified water column to the edge of the surf zone.