IB05-4 ORAL

YELLOW SEA OCEAN-ACOUSTIC SOLITON MODELLING STUDIES

A.WARN-VARNAS (Naval Research Laboratory, Stennis Space Center, MS, 39529, USA, varnas@nrlssc.navy.mil); S. Chin-bing (Naval Research Laboratory, Stennis Space Center, MS, 39529, USA, chinbing@nrlssc.navy.mil); D. King (Naval Research Laboratory, Stennis Space Center, MS, 39529, USA, king@nrlssc.navy.mil); K. Lamb (University of Waterloo, Waterloo, Ontario, N2L3G1,Canada, kglamb@moisie.math.uwaterloo.ca); M. Teixeira (Polytechnic University of Puerto Rico, San Juan,PR 00919,USA, mteixeir@caribe.net)

The study is centered in an area south of the Shandong peninsula where 20 to 30 m topographic variations over a distance of 10 to 20 km are found to occur. Along the southern boundary of the region the semi-diurnal tidal strength magnitude varies from .6 m/sec to 1.2 m/sec, Guo-Hong(1994). We show that, for summer conditions, the existing semi-diurnal tidal flow over the topographic variations leads to the formation of internal bores and solitons in simulations with the Lamb(1994) nonhydrostatic model. The soliton motion is felt throughout the water column and can influence biological processes and sediment. In large scale models, tidally driven soliton have to be parameterized. For the Shandong area we analyzed summer SAR observations that track soliton trains from their surace roughness signature. Comparisons of surface spectra obtained from SAR observations and model simulations are performed together with sensitivity to model parameters. In the same area, Zhou, Zhang, and Rogers(1991) conducted acoustical measurements and showed an anomalous transmission loss in acoustical intensity at around 630 Hz. We investigate this phenomena by considering the interaction of the acoustic field with the soliton trains along the path of their propagation. Joint oceanographic and acoustical predictions are undertaken. Calculations of the full acoustic field is conducted with the parabolic (PE) acoustical model. An analysis of the energy distribution among the acoustical normal modes and bottom loss is performed in presence of solitons. Transmission loss patterns are presented for diverse conditions along the path of propagation