The University of Rhode Island and Johns Hopkins University will undertake a collaborative, multidisciplinary instru- mentation development project to develop and implement a means of increasing capabilities to resolve interactions betweenparticles and small scale physical processes in the ocean by simultaneously measuring particle properties and small scale motions of the fluid surrounding it. The project involves laser optic holography and fluid mechanics methods to derive information about plankton dynamics and particle characterization. A pulsed ruby laser holocamera will be modified for use in the ocean and will use recent advances in holography and digital image processing. Design criteria call for in situ measurement of particle number, size, distribution, type, and orientation and inter-particle distances over a size range of 10 microns to 5 cm. Instantaneous velocity of all particles within a sample volume would also be measured by adapting triple- pulse techniques used for motion sensing within laser sheets. The proposed instrument will be usable in the laboratory or in the field, when attached to a submersible. The development of a motion sensing holocamera is driven by a growing recognition that a new class of instruments is required to address a series of critical questions in ocean science and marine fluid mechanics. Presently available instrumentation is inadequate to address and test hypotheses concerning complex physical-particle interactions of plankton dynamics and boundary layer fluid dynamics.
