A PARTICLE FLUX MEASUREMENT SYSTEM

THIS PROJECT INVOLVES THE DESIGN AND EVALUATION OF AN IN-SITU MARINE PARTICLE FLUX MEASUREMENT SYSTEM. THIS PLANNED DEVICE IS DESIGNED TO OVERCOME THE TWO MAJOR DEFICIENCIES OF SEDIMENT TRAPS: COLLECTOR EFFICIENCY AND SAMPLE INTEGRITY. TO AVOID COLLECTION EFFICIENCY PROBLEMS, THE INSTRUMENT'S FLOW DUCT IS ALIGNED ALONG THE PREDOMINANTLY HORIZONTAL AMBIENT CURRENT AND IS ALSO ISOLATED FROM THE VERTICAL MOTIONS OF THE MOORED LINE. SAMPLE INTEGRITY IS NO LONGER A PROBLEM BECAUSE THE DEVICE MONITORS PARTICLES OPTICALLY WHILE THEY SETTLE. THIS NEW DESIGN INTEGRATES TWO PARTICLE MONITORING TECHNIQUES TO COVER THE WIDE SIZE RANGE OF MARINE PARTICLES: (1) A NEAR-FORWARD SCATTERING MEASUREMENT TO ESTIMATE THE CONCENTRATION OF PARTICLES LESS THAN 100 MICRONS IN SIZE AND(2) A SHADOWGRAPH TECHNIQUE TO MEASURE LARGER PARTICLES. THE PHASE I EVALUATION CONSISTS OF SETTING UP A LABORATORY VERSION OF THE SYSTEM TO TEST THE PERFORMANCE OF THE TWO PARTICLE SENSING TECHNIQUES. ANALYTICAL EFFORT IS ALSO DEVOTED TO STUDYING THE EFFECT OF SOME RESIDUAL HYDRODYNAMICDISTURBANCES ON THE PERFORMANCE OF THE SYSTEM.