The spectral characteristics and kinematics of short-period internal waves on the Hawaiian shelf

Abstract

Based on the results of analyzing the characteristics of currents and temperature measured in the water space of the Mamala Bay (the Island of Oahu, Hawaii), we investigate the main properties of the field of short-period internal waves, which is very complex. We focus on analyzing the spectral characteristics and orbit parameters for waves with a period of 20 minutes. The results of investigations reveal two types of short-period internal waves for this area: intense and fast waves propagating predominantly toward the ocean and weaker and slower waves propagating mainly toward the coast. Suppositions are made on how these waves form: the strong and fast waves are likely to be caused by the decay of locally generated internal tides near the shelf edge, while the weak and slow and very short waves seem to result from the specific interaction between the pycnocline and strong tidal currents over a steep slope.