A Model of Non-Stationary Time-Series to Predict Surface Salinity Off-Shore the Columbia River

The Columbia River discharge plays a central role in North-East Pacific Ocean coastal ecosystem dynamics. A model is developed to predict non-stationary surface-salinity time-series in the North Pacific Ocean off-shore the Columbia River. The model takes wind velocities and Columbia River discharge as inputs only. Wind velocities are converted to smoothed wind stresses which are then integrated to "pseudo advective paths", an indicator function for north or south favorable advective paths of a surface water parcel. Surface salinity values can be predicted, assuming that the salinity values change linearly with pseudo advective path and that salinity ranges between ocean and estuary entrance salinity. Estuary entrance salinity is modeled linearly as function of river flow. Although the model works rather poorly in a quantitative sense (Averaged squared error: Ο(10) ), it is able to predict general salinity trends, and plume as well as ocean events (~90% of total events recovered). The model can be a useful tool for studies of Columbia River plume migration, and thus contributes to the understanding of coastal ecosystem dynamics.