Effect of a Hawaiian Seamount on Vertical Density Structure and Internal Waves
The proposed research aims to study and compare the vertical density structure of the water column on and around a seamount. Seamounts and similar bathymetry are known to stimulate instability in vertical structure, often in the form of the generation of internal waves called internal tides. This study aims to assess the influence of seamount topography on oceanic density stratification. An understanding of the effect of the seamount on stratified waters will be gained by studying the vertical profiles of water on and around Cross Seamount, a seamount off the Hawaiian Islands in the North Pacific. The work intends to make use of both Acoustic Doppler Current Profiler (ADCP) data and Conductivity/Temperature/Depth CTD data to sample the vertical structure of the water. The Richardson Number will also be incorporated into the study to determine if and quantify whether Cross Seamount perturbs the water above it enough to cause shear instability. The Richardson Number (Ri) is a dimensionless number which indicates water column stability. If the water column in unstable then shear instability will result; this is essentially turbulent interaction of two layers of fluid. The justification behind this research is that internal waves are significant physical phenomena which have influence on local biology and chemistry as well as being important in the study of underwater acoustics. It can be hypothesised that the Cross Seamount will cause observable shear instability in the vertical structure of the water column when compared with off-seamount locations.