Interannual Predictability of North Atlantic Sea Level Dynamics

A large degree of uncertainty remains in both the temporal and spatial variability of regional sea level predictions. This study aims to constrain the uncertainty, due to both the atmospheric and ocean states, by examining the dynamics and predictability of sea surface height (SSH) in the North Atlantic on interannual timescales. An evaluation of the typical timescales of SSH predictability in an idealised model set up of a flat bottomed, barotropic double gyre has been undertaken. Moreover, the sensitivity of the SSH predictability to applied wind stress perturbations of differing magnitudes has been examined. The timescales of predictability present were evaluated by using linear inverse modeling techniques to represent the system by a statistical, yet dynamical, model. It was found that potential for interannual predictability exists and is largely located both in the jet region and in the vicinity of the western boundary. In order to investigate the mechanism behind this interannual variability and predictability, further analysis of the ocean momentum budget was carried out with a focus on the eddy-mean flow interaction. Results indicate that further studies, where particular emphasis is placed on sea level anomalies near the coast, could inform measurements by examining which time and spatial resolutions are needed to obtain relevant measures of predictability.