Surface Drift and Dispersion in a Multiply Connected Fjord System

Abstract

The deployment of 206 surface drifters over 3 years in a fjord system in northern British Columbia allows examination of drift and dispersion in complex coastal regions on time scales up to 10 days. The surface drift is found to be seasonally variable, with stronger dispersion and outflows in the spring and fall, and negligible outflow in the summer. Dispersion at time scales less than 10 hr is well described by fractional Brownian motion, where the drifter tracks exhibit fractal characteristics with a dimension of 1.34 over scales of 2 to 13 km. Drifters are found to reach less energetic nearshore regions within 12–15 hr, which slows along-channel dispersion. The comparison of the drifter statistics (from 2014–2016) with observations of the spatial distribution of oil sheen following an oil spill in 2006 shows that the drifter results provide a reasonable proxy for oil drift in this area. A statistical model for the extent of along-channel transport of spilled oil is proposed for use in planning emergency response activities in the area.