STOCHASTIC INTERPOLATION AS A MEANS TO ESTIMATE OCEANIC FIELDS

The method of stochastic interpolation (conditional simulation) is int roduced as a means to interpolate/extrapolate a scalar or vector field of an oceanic variable, eg. currents. Conditional simulation produces the synthesis of a random field that is forced to agree with simultan eous measurements in the same time interval and area where the input d ata are being synthesized. The conditional simulation is applied to th e vector field for two California current measurement programs (Coasta l Ocean Dynamics Experiment (CODE) and Central California Coastal Circ ulation Study (CCCCS), north and south of San Francisco, respectively) . These field programs covered different areas and were characterized by different instrument spacings. The influence of these spatial facto rs shows up in the quality of the conditional simulations, i.e. a smal ler area and a tighter mooring array led to more PhYsically reasonable flow realizations. The various realizations provided by a series of c onditional simulations allow confidence intervals to be defined. Other uses for this technique include optimization of current-meter (or oth er sensor) placement and the specification of initial or boundary cond itions for numerical models. This latter function could be invoked whe n real data are sparse or when the data that are available are overly smooth and do not contain enough of the variability of the natural sys tem.