Kinematic mapping of circulation and water properties off Pt. Conception, California

One of the most important challenges of coastal ocean observing systems is how to meld together data from different observing platforms. Coastal ocean observing systems typically include data from a number of measuring platforms and platform types. Some are deployed as part of the observing system, while others exist independently. Instrument platforms may be moved added, or permanently removed from the system. At any given time at least some sensors are inoperable. Moreover, different parts of the database are usually gathered with different sampling schemes. The Minerals Management Service funded Santa Barbara Channel - Santa Maria Basin circulation study provides a prime example of these challenges. The study has taken place over the last decade. Platforms used in it include moorings, drifters, survey data, and meteorological stations. Over the course of the study, the observing system changed in response to differing scientific objectives, but some elements remained constant. We have adopted a 2 part approach in mapping and analyzing the data. First, we identified large-scale synoptic states which are clearly expressed in the unchanging elements of the observations. Second, we used the large scale states to inform objective maps of the data. The large-scale states provide reasonable interpolations of often sparse data while the objective maps provide consistent kinematic interpolations of the data and error estimates. We map the data in an along-shelf and cross-shelf coordinate system with realistic, anisotropic correlation scales. The mapping region extends approximately 250 km along the shelf and 50 km across it. This approach has been used to map surface and subsurface circulation time series, meteorological time series, and survey observations on comparable scales. Circulation and wind fields have been mapped from November 1992 to November 1999. The circulation results have an important practical benefit in that they have some ability to predict parcel trajectories. Comparisons of the mapped circulation, wind, and survey fields are made possible by the objective mapping procedure. These comparisons highlight the relative importance of different dynamical processes in the region. The mapped fields are also ideal for assimilation into numerical models and have been provided to numerical modelers for these purposes.