Current profiles around the mound under different stratification conditions

Abstract

Generally, currents vary with density conditions. This paper describes mechanisms of currents around the mound at Ohfunato Bay in accordance with density difference between inside and outside the bay. It is revealed that mechanisms of currents are greatly related with the rainfall depend on the results of the field measurement in summer. Immediately after rainfall, low density water due to rainfall remains at the surface layer outside the bay. This water body mixes with the high-density water body at bottom layer outside the bay, and so the density of water body outside the bay becomes small. Under this condition, the inflow of low-density water at middle layer and the outflow of the bottom water inside the bay are stronger than usual. Thereafter, the density above middle layer inside the bay becomes small uniformly due to the inflow of low-density water. When low-density water body disappears outside the bay, the density of water body going into the bay becomes big.Therefore this water body comes to go into the bottom layer inside the bay. This current supplies oxygen to the bottom layer, thereby the depleted water body inside the bay recovers rapidly.