A numerical model for refraction of ocean swell by currents associated with a warm core ring was developed and tested with Seasat synthetic aperture radar (SAR) data. The wave field of SAR orbit 1232 was measured using optical Fourier transforms. The wave refraction model produced rays by simultaneous, numerical integration of the Hamiltonian ray equations applied to a moving medium. Wave orthogonals were constructed from wave number vectors calculated at each incremental time step. The flow field used by the model to simulate a warm ring was a steady, circular jet, with the radial profile of tangential velocity composed of a power function joined to a Gaussian. Initial wave conditions for simulation of refraction by the SAR‐imaged ring were determined from measurements outside the ring. No data were available from which to determine the current field of the SAR‐imaged ring, so the current field input to the model was adjusted until the output wave field most nearly resembled the SAR observations. The relative locations of convergence and divergence of rays were as observed on the SAR image, and the relative energy density in crossed seas was correctly predicted. However, predicted patterns of wavelength variation (presuming that incident waves were uniform in wavelength) were not observed.

Destratification in the York River during high spring tides is the result of the interruption of normal two-layer estuarine flow by the advection of relatively fresh water into the river mouth from the Chesapeake Bay. This advection is due to the presence of a longitudinal salinity gradient in the bay and a difference in the tidal current phase between the river and the bay. Similar behavior is seen in other subestuaries of the Chesapeake Bay and may be common in subestuary-estuary interactions.

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A method of determining thermal diffusivity in thin plates is presented. The method, using infrared images of evolving thermal patterns previously injected with a laser, is noncontacting, one-sided, and remote. It does not require independent estimates of either the emissivity of the sample or the sample thickness. With a line-segment pattern for thermal input, it yields the inplane components of the diffusivity tensor in anisotropic materials and also the rate of heat loss to the environment of the plate. Two methods of data analysis are presented, one corresponding to a heating line of general cross section and the other considering a Gaussian cross section, thereby saving considerable computer time. Both methods produce a statistical evaluation of measurement quality as well as estimates of diffusivity and loss rate. Results are shown for plates of metals and graphite-epoxy composite materials. Principal components and orientation for the diffusivity tensor are obtained in the anisotropic graphite-epoxy sample.