Diffusivity of suspended matter in the caribbean sea

Abstract

Total suspended matter (TSM) has been determined by gravimetric analysis at nine stations in the Caribbean Sea. Vertical eddy diffusivities near the surface and bottom are calculated by applying a simplified diffusion equation to the mean vertical profiles of TSM. The eddy diffusivities range from 1 to 8 cm2/sec for the upper layer down to about 150 meters, but they are smaller in the bottom region up to about 80 meters from the bottom, ranging from 0.2 to 2 cm2/sec. Mid-depth (300 meters ∼1500 meters) maximum concentrations in the eastern stations are interpreted as advection of scouring at the sill depth of the Mona passage. The transport equation balanced with horizontal advection and vertical diffusion terms yields a solution that can be fitted to the vertical distributions near the mid-depth maximums, resulting in estimates of advection velocity of about 1 cm/sec and vertical eddy diffusivity of 5–10 cm2/sec.