NUMERICAL MODELING OF A RIVER-DOMINATED ESTUARY: REPRESENTING SHARP DENSITY GRADIENTS
The Columbia River Estuary is characterized by large river discharge and high-energy ocean-estuary exchange. Numerical modeling of the system is challenging due to strong tidal currents and sharp density gradients, as well as complex coastal processes including plume dynamics and coastal upwelling. This presentation reports on improvements of the Virtual Columbia River, a multi-scale unstructured grid modeling system. In 2012 two measurement campaigns were carried out aiming to collect high-resolution data of key physical processes in the North Channel of the estuary. The instrumentation included a shipborne Winched Profiler platform and two autonomous underwater vehicles. The two cruises focused on high and low river discharge conditions, respectively, yielding an exceptionally detailed data set of the circulation. The model is capable of reproducing the observed circulation features with good accuracy: the timing and shape of the salt pulses is generally very well captured. The model has more difficulty in representing the sharp density gradients that frequently occur at high flow and neap tide conditions. Mixing processes are comparable to the observations, except for differences due to underestimated stratification.
Karna, T., Oregon Health & Science University, USA, firstname.lastname@example.org
Baptista, A. M., Oregon Health & Science University, USA, email@example.com
Lopez, J., Oregon Health & Science University, USA, firstname.lastname@example.org
McNeil, C., University of Washington, USA, email@example.com
Sanford, T. B., University of Washington, USA, firstname.lastname@example.org
Presentation is given by student: No