EGU2020-4992
https://doi.org/10.5194/egusphere-egu2020-4992
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Direct temporal cascade of temperature variance in eddy-permitting simulations of multidecadal variability

Antoine Hochet1, Thierry Huck1, Olivier Arzel1, Florian Sevellec1, Alain Colin de Verdiere1, Matthew Mazloff2, and Bruce Cornuelle2
Antoine Hochet et al.
  • 1universite de bretagne occidentale, Brest, France (antoine.hochet@univ-brest.fr)
  • 2Scripps institution of Oceanography, La Jolla, California, USA

The North Atlantic is characterized by basin-scale multidecadal fluctuations of the sea surface temperature with periods ranging from 20 to 70 years.
One candidate for such a variability is a large-scale baroclinic instability of the North Atlantic Current. Because of the long time scales involved, most of the studies devoted to this problem are based on low resolution numerical models leaving aside the effect of explicit meso-scale eddies.   
How high-frequency motions associated with the meso-scale eddy field affect the basin-scale low-frequency variabiliy is the central question of this study.

This issue is addressed using an idealized configuration of an Ocean General Circulation Model at eddy-permitting resolution (20 km). A new diagnostic allowing the calculation of nonlinear fluxes of temperature variance in frequency space is presented. Using this diagnostic, we show that the primary effect of meso-scale eddies is to damp low frequency  temperature variance and to transfer it to high frequencies.

How to cite: Hochet, A., Huck, T., Arzel, O., Sevellec, F., Colin de Verdiere, A., Mazloff, M., and Cornuelle, B.: Direct temporal cascade of temperature variance in eddy-permitting simulations of multidecadal variability, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4992, https://doi.org/10.5194/egusphere-egu2020-4992, 2020

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