Boundary options for a research area within Gray's Reef National Marine Sanctuary

Gray’s Reef National Marine Sanctuary (GRNMS) is exploring the concept of a research area (RA) within its boundaries. The idea of a research area was first suggested in public scoping meetings held prior to the review of the Gray’s Reef Management Plan. An RA is a region specifically designed for conducting controlled scientific studies in the absence of confounding factors. As a result, a multidisciplinary group gathered by GRNMS was convened to consider the issue. This Research Area Working Group (RAWG) requested that a suite of analyses be conducted to evaluate the issue quantitatively. To meet this need, a novel selection procedure and geographic information system (GIS) was created to find the optimal location for an RA while balancing the needs of research and existing users. This report and its associated GIS files describe the results of the requested analyses and enable further quantitative investigation of this topic by the RAWG and GRNMS.

Comparisons of open boundary conditions in a barotropic model of the northern Arabian Sea

These simulations are focused on the sensitivity of the barotropic ocean non-linear model to the various open boundary conditions (OBCs). Different OBCs from gradient to radiation condition are examined to determine the best result and help to choose the most appropriate OBCs. Since the interior points are changing with time both implicit and explicit forms are applied. The simulations showed that the interior flow is sensitive to changes in the OBCs and the results are highly dependent on the bathymetry of the area. When a constant depth (100m) is used, the circulation pattern with all OBCs is same. The best boundary conditions are Orlanski Radiation and its modified form. These boundary conditions produce identical adjustment in velocity and are determined to be satisfactory for both constant depth and actual bathymetry.