Reconstructing the Parameters of Internal Tidal Bores in the Banda Sea from Satellite Remote Sensing Data

Abstract

This article presents an algorithm for estimating the vertical displacements of isopycn and horizontal current velocities caused by internal tidal borings from their manifestations in the roughness field on satellite images of the Banda Sea. The calculation algorithm is formulated within the framework of the Korteweg-de Vries equation (KdV), augmented with a term taking into account the cylindrical divergence. The coefficients of the KdV equation — quadratic nonlinearity, dispersion and tidal linear internal wave velocity — were calculated using the mean — climatic density profile in the Banda Sea. The leading soliton velocity and wavelength in the rear zone of the internal tidal borings were determined from satellite images. Using the proposed methodology, estimates of the maximum vertical displacement of the pycnocline/maximum amplitude of the leading soliton and the maximum velocity of surface currents induced by the internal tidal borings were obtained. It follows from the analysis of satellite images that the internal tidal borings in the Banda Sea are transformed under the action not only of nonlinearity and dispersion, but also of cylindrical divergence. It is shown in the framework of the knoidal model of internal tidal borings that in the process of evolution the energy of its leading and subsequent waves is attenuated due to the cylindrical divergence. This attenuation is estimated when the leading soliton travels a distance equal to twice the tidal period.