A model of the plume front of the Pearl River Estuary, China and adjacent coastal waters in the winter dry season

The Princeton Ocean Model was employed for a detailed examination of the plume front dynamics of the Pearl River Estuary (PRE), China, and the small scale circulation associated with the plume front in the dry season during the winter. In general, the plume front in the PRE is formed by the salinity gradient between the riverine water and the higher salinity shelf waters. Although the basic features in the deeper waters of the plume front of the PRE are similar with respect to tidal variations and, wind and river discharge, both the tide and river discharge affect the subsurface front, while these dynamic factors modify the surface features of the plume front. A two-layer circulation in the vertical occurs within the plume front, while at the same time a horizontal circulation converges in the plume frontal zone. The density-driven current that is associated with the frontal dynamics plays a dominant role in modifying the dynamic behavior (both the strength and the scale) of the circulation. Basically, the small scale circulation associated with the plume front dynamics dominates the estuarine dynamics as well as the dynamic behavior of the western coastal part of the plume front. Moreover, most of the diluted water is transported along the plume front from the estuary to the western coastal region due to the fact that most of the water converges on two sides of the plume front. The sub-tidal current plays an important role in transporting suspended substances along the plume front during a spring tide due to the non-linear effect of the tide on the heterogeneous density field and on the topography. (C) 2004 Elsevier Ltd. All rights reserved.