The influence of local and remote winds on the synoptic sea level variability in the Gulf of Saint Lawrence

Abstract

The influence of local and remote winds on sea level and circulation variability in the synoptic band in the Gulf of Saint Lawrence is examined. We use two years of winter sea level data from the Gulf of Saint Lawrence, a statistical regression model and a linear, barotropic, depth-averaged numerical model to separate the effect of local and remote forcing. The boundary conditions of the numerical model are determined using an adjoint data assimilation technique. The results show that the influence of the local wind on sea level is negligible over the study period. Most of the variability is introduced through the open boundaries of the Gulf of Saint Lawrence, notably Cabot Strait. The remote forcing can be related to the large-scale wind fields over the adjacent Newfoundland and Labrador Shelves. The numerical model results provide a basis for operational modelling of the synoptic variability in the Gulf of Saint Lawrence.