Preparing to predict: The Second Autonomous Ocean Sampling Network
(AOSN-II) experiment in the Monterey Bay
S.R. Ramp, R.E. Davis, N.E. Leonard, I. Shulman, Y. Chao, A.R. Robinson, J. Marsden, P. Lermusiaux,
D. Fratantoni, J.D. Paduan, F. Chavez, F.L. Bahr, S. Liang, W. Leslie and Z. Li
Deep-Sea Research II, vol. 56, 68-86, 2009.
The Autonomous Ocean Sampling Network Phase Two (AOSN-II) experiment
was conducted in and offshore from the Monterey Bay on the central California coast
during July 23-September 6, 2003. The objective of the experiment was to learn how to
apply new tools, technologies, and analysis techniques to adaptively sample the coastal
ocean in a manner demonstrably superior to traditional methodologies, and to use the
information gathered to improve predictive skill for quantities of interest to end-users.
The scientific goal was to study the upwelling/relaxation cycle near an open coastal bay
in an eastern boundary current region, particularly as it developed and spread from a
coastal headland. The suite of observational tools used included a low-flying aircraft, a
fleet of underwater gliders, including several under adaptive autonomous control, and
propeller-driven AUVs in addition to moorings, ships, and other more traditional
hardware. The data were delivered in real-time and assimilated into the Harvard Ocean
Prediction System (HOPS), the Navy Coastal Ocean Model (NCOM), and the Jet
Propulsion Laboratory implementation of the Regional Ocean Modeling System
Two upwelling events and one relaxation event were sampled during the
experiment. The upwelling in both cases began when a pool of cold water less than 13 °C
appeared near Cape Aņo Nuevo and subsequently spread offshore and southward across
the bay as the equatorward wind stress continued. The primary difference between the
events was that the first event spread offshore and southward, while the second event
spread only southward and not offshore. The difference is attributed to the position and
strength of meanders and eddies of the California Current System offshore which blocked
or steered the cold upwelled water. The space and time scales of the mesoscale variability
were much shorter than have been previously observed in deep-water eddies offshore.
Additional process studies are needed to elucidate the dynamics of the flow.
(5.87 MB pdf)
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