Wind Forced Variability in Eddy Formation, Eddy Shedding, and the Separation of the East Australian Current - INSU - Institut national des sciences de l'Univers Access content directly
Journal Articles Journal of Geophysical Research. Oceans Year : 2017

Wind Forced Variability in Eddy Formation, Eddy Shedding, and the Separation of the East Australian Current

Christopher Y. S. Bull
  • Function : Author
Andrew E. Kiss
  • Function : Author
Matthew H. England
  • Function : Author
Erik van Sebille
  • Function : Author

Abstract

The East Australian Current (EAC), like many other subtropical western boundary currents, is believed to be penetrating further poleward in recent decades. Previous observational and model studies have used steady state dynamics to relate changes in the westerly winds to changes in the separation behavior of the EAC. As yet, little work has been undertaken on the impact of forcing variability on the EAC and Tasman Sea circulation. Here using an eddy-permitting regional ocean model, we present a suite of simulations forced by the same time-mean fields, but with different atmospheric and remote ocean variability. These eddy-permitting results demonstrate the nonlinear response of the EAC to variable, nonstationary inhomogeneous forcing. These simulations show an EAC with high intrinsic variability and stochastic eddy shedding. We show that wind stress variability on time scales shorter than 56 days leads to increases in eddy shedding rates and southward eddy propagation, producing an increased transport and southward reach of the mean EAC extension. We adopt an energetics framework that shows the EAC extension changes to be coincident with an increase in offshore, upstream eddy variance (via increased barotropic instability) and increase in subsurface mean kinetic energy along the length of the EAC. The response of EAC separation to regional variable wind stress has important implications for both past and future climate change studies.
Fichier principal
Vignette du fichier
JGR Oceans - 2017 - Bull - Wind Forced Variability in Eddy Formation Eddy Shedding and the Separation of the East.pdf (2 Mo) Télécharger le fichier
Origin Publisher files allowed on an open archive

Dates and versions

insu-03706517 , version 1 (28-06-2022)

Licence

Copyright

Identifiers

Cite

Christopher Y. S. Bull, Andrew E. Kiss, Nicolas C. Jourdain, Matthew H. England, Erik van Sebille. Wind Forced Variability in Eddy Formation, Eddy Shedding, and the Separation of the East Australian Current. Journal of Geophysical Research. Oceans, 2017, 122, pp.9980-9998. ⟨10.1002/2017JC013311⟩. ⟨insu-03706517⟩
52 View
22 Download

Altmetric

Share

Gmail Mastodon Facebook X LinkedIn More