High frequency rough surface parabolic equation modeling for underwater acoustic communications

In this paper, we propose to develop an effective and efficient computational modeling technique to characterize the statistical properties that govern the performance and capacity of an underwater acoustic communication link. Specifically, we consider the challenging shallow water environment with a moving rough sea surface as the primary source of temporal variations. We incorporate a realistic sea surface for wind driven waves generated by the surface spectrum. We use meteorological and oceanic data measured by National Data Buoy Center (NDBC) buoy 44014 (36.611N 74.836W) and model estimates of downward radiation fluxes at its location to produce a time series, covering all of 2004 with 3 hr spacing, of the input parameters needed by the analytical spectral model. For one particular set of parameters, typical of March, we generate sea surface realizations and study their effect on acoustic propagation. We extend a parabolic equation (PE) model to compute the propagation of a high frequency, wide-band acoustic transmission with a time-varying sea surface. We provide numerical results of received signal power as a function of range and depth. Our modeling approach has both physical applicability and computation feasibility to generate channel impulse responses useful for adaptive underwater communications.