A New Framework for Wind Convergence over Western Boundary Currents

It is now well-known that western boundary currents anchor vertical ascent deep into the atmosphere in the climatological mean, resulting in a striking imprint of the meandering ocean currents on the near-surface and upper tropospheric wind convergence fields. Traditionally, this air-sea coupling has been described mechanistically through time-mean processes.

Here, by decomposing the atmosphere into frontal and non-frontal components, we illustrate that the oceanic imprint on both the near-surface and upper tropospheric time-mean wind convergence fields can actually be explained almost entirely by the frontal components alone (i.e. on a synoptic time-scale).

Critically, this suggests that the influence of western boundary currents on many aspects of the climatological atmosphere can be inferred from interactions occurring on a synoptic time-scale. For example, recent studies have shown perturbations in western boundary currents impacting mean atmospheric fields on a global scale. The results presented here suggest these induced teleconnections can potentially be attributed to the discrete interactions between oceanic and atmospheric fronts.