Date of Award
Program or Major
Master of Science
Glacial troughs are ﬂat-bottomed, steep-sided submarine valleys, which almost or entirely
incise the shelf, that signiﬁcantly alter coastal circulation. A barotropic, linear, steady-state
model is used to quantify this alteration as a function of shelf geometry. These model results
demonstrate that troughs eject most of the shelf transport oﬀshore to the slope. This oﬀshore
ejection diminishes wind-driven alongshore transport downwave of the trough; downwave is
the direction of long coastal trapped wave propagation.
Oﬀshore ejection is caused by bottom friction dissipating relative vorticity. Troughs
enhance oﬀshore ejection by generating relative vorticity. This is because linear ﬂows on an
f-plane (used in this model) follow isobaths to ﬁrst order. Troughs on the shelf generate
relative vorticity through two means: the curving isobaths, which deﬁne the trough, steer
ﬂows, creating a “ﬂow curvature,” and the narrowed shelf, between the coast and trough,
accelerates the ﬂow and creates a “ﬂow shear.” The relative importance of these two trough
induced mechanisms and a quantiﬁcation of the net ejection is found with this model.
Hampson, Patrick, "Glacial Troughs Eject Wind-Driven Shelf Circulation to the Slope" (2020). Master's Theses and Capstones. 1343.