Date of Award
Program or Major
Earth and Environmental Science: Oceanography
Doctor of Philosophy
Fluctuating winds change the interaction between an estuary and its adjacent coastal ocean. This change in the interaction determines how the wind-induced changes in the estuary influence the near-shore coastal ocean and vice-versa.
The first chapter examines the water properties in the near-shore coastal region close to estuaries after coastal upwelling. In regions where the time-integrated upwelling and down-welling wind stresses are comparable, there exists a region in the direction of a coastal Kevin wave propagation from an estuary, where the arrival of the plume in the near-shore region prevents the upwelled front from returning to the coast. The weakened vertical stratification in the plume during down-welling winds allows vertical mixing, so the weak cross-shore flow in the plume stops the front from returning to the coast.
The second chapter examines the transient response of the interaction between an estuary and its adjoining coastal ocean, when forced by weather-band fluctuations in the wind. Over timescales shorter than the time taken for the estuary to adjust to a new steady state, Tadj, the initial stratification of an estuary and the coastal ocean control the influence of fluctuating winds on the salt exchange between the two regions. The wind-induced mixing in the estuary has by far the greatest effect on the salt exchange, compared to the coastal upwelling and down-welling. The changes in the salt exchange are largely due to changes in the salinity leaving and entering the estuary, and not the volume exchange.
The final chapter examines how the steady state of an estuary is altered, when forced by weather-band fluctuations in the wind. For timescales longer than Tadj, the influence of fluctuating winds on the stratification or the exchange of an estuary is not significant, but instead the fluctuating winds alter the salt intrusion length of the estuary. However, when Tadj (when forced by fluctuating winds) is short compared to the time of the initial change caused by the vertical mixing, the influence of fluctuating winds in a stratified estuary reduces the stratification and the exchange.
Rao, Shivanesh Arvinda, "Interaction between the coastal ocean and the estuarine systems" (2012). Doctoral Dissertations. 704.