Objective analysis of a coastal ocean eddy using satellite AVHRR and in situ hydrographic data

Abstract

A common characteristic of the interaction between the coastal topography and eastern boundary currents (EBC) is the appearance of cold filaments and mesoscale eddies. Hydrographic and satellite temperature data obtained during a cruise on board R/V Point Sur off Point Arena, California, in May 1993 were analyzed to study a particular eddy field in this area. The hydrographic data was first used to verify the remotely sensed surface temperature field, using three dimensional data visualization. Selected vertical levels from each hydrographic station were then interpolated into a broader, finer resolution grid domain in preparation for an eventual model initialization, using multiquadric interpolation. The results verify the existence of the eddy and show its signature in the vertical to about 300 meters depth. A sensitivity study of interpolation parameters was performed to evaluate approximately the optimal set of parameters, showing that the multiquadric interpolation resolves very well the temperature field in the upper levels and introduces small amplitude, small scale noise in the deeper levels. This noise can be eliminated by a more thorough parameter sensitivity study.