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ESTUARINE-OCEAN EXCHANGE IN A NORTH PACIFIC ESTUARY: COMPARISON OF STEADY STATE AND DYNAMIC MODELS
Citation:
FRICK, W. E., T. KHANGAONKAR, A. C. SIGLEO, AND Z. YANG. ESTUARINE-OCEAN EXCHANGE IN A NORTH PACIFIC ESTUARY: COMPARISON OF STEADY STATE AND DYNAMIC MODELS. Estuarine Coastal and Shelf Science. Elsevier Science Ltd, New York, NY, 74(1-2):1-11, (2007).
Impact/Purpose:
A main objective of this task is to combine empirical and physical mechanisms in a model, known as Visual Beach, that
- is user-friendly
- includes point and non-point sources of contamination
- includes the latest bacterial decay mechanisms
- incorporates real-time and web-based ambient and atmospheric and aquatic conditions
- and has a predictive capability of up to three days to help avert potential beach closures.
Description:
Nutrient levels in coastal waters must be accurately assessed to determine the nutrient effects of increasing populations on coastal ecosystems. To accomplish this goal, in-field data with sufficient temporal resolution are required to define nutrient sources and sinks, and to ultimately calculate nutrient budgets. Models then are required for the interpretation and analysis of data sets. To quantify the coastal ocean nitrogen input to Yaquina Bay, Oregon, nitrate concentrations were measured by a moored sensor hourly for one month during summer upwelling some distance outside the estuary entrance jetties. The time series results then were interpreted using a steady state model (Visual Plumes' PDSW) and a hydrodynamic model, the Finite Volume Coastal Ocean Model (FVCOM). The results showed that the steady-state plume model simulates observed velocity and concentration data fairly well during periods of strong discharge velocity and weak ambient coastal currents. FVCOM was judged to give better estimates under all other ambient current conditions, although the data from the mooring cannot be used to prove this assertion as stronger currents would deflect the plume away from the mooring. Nevertheless, plume models may be useful in establishing boundary and initial conditions for hydrodynamic models.