TY - JOUR
T1 - Regional and temporal variability of lateral mixing in the north atlantic
AU - Bolton, Thomas
AU - Abernathey, Ryan
AU - Zanna, Laure
N1 - Funding Information:
This work was funded by the Natural Environment Research Council (NERC; Award NE/L002612/1). The altimeter products were produced by Ssalto/Duacs and distributed by AVISO, with support from Cnes (www.aviso.altimetry.fr/duacs). The bathymetry product was produced by National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce (doi:10.1594/PANGAEA.769615). R.P.A. acknowledges support from NSF Award OCE 1553593.
Funding Information:
Acknowledgments. This work was funded by the Natural Environment Research Council (NERC; Award NE/L002612/1). The altimeter products were produced by Ssalto/Duacs and distributed by AVISO, with support from Cnes (www.aviso.altimetry.fr/duacs). The bathymetry product was produced by National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commerce (doi:10.1594/PANGAEA.769615). R.P.A. acknowledges support from NSF Award OCE 1553593.
Publisher Copyright:
© 2019 American Meteorological Society.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - © 2019 American Meteorological Society. Geostrophic eddies contribute to the mixing of heat, carbon, and other climatically important tracers. A passive tracer driven by satellite-derived surface velocity fields is used to study the regional and temporal variability of lateral eddy mixing in the North Atlantic. Using a quasi-Lagrangian diffusivity diagnostic, we show that the upstream region (808–508W) of the Gulf Stream jet exhibits a significant mixing barrier (with diffusivity of ’1 ˣ 103 m2 s-1 ), compared to the downstream region (508–108W), which displays no mixing suppression (’10 ˣ 103 m2 s-1 ). The interannual variability is 10%–20% of the time mean in both regions. By analyzing linear perturbations of mixing-length diffusivity expression, we show that the across-jet mixing in the upstream region is driven by variations in the mean flow, rather than eddy velocity. In the downstream region, both the mean flow and eddy velocity contribute to the temporal variability. Our results suggest that an eddy parameterization must take into account the along-jet variation of mixing, and within jets such diffusivities may be a simple function of jet strength.
AB - © 2019 American Meteorological Society. Geostrophic eddies contribute to the mixing of heat, carbon, and other climatically important tracers. A passive tracer driven by satellite-derived surface velocity fields is used to study the regional and temporal variability of lateral eddy mixing in the North Atlantic. Using a quasi-Lagrangian diffusivity diagnostic, we show that the upstream region (808–508W) of the Gulf Stream jet exhibits a significant mixing barrier (with diffusivity of ’1 ˣ 103 m2 s-1 ), compared to the downstream region (508–108W), which displays no mixing suppression (’10 ˣ 103 m2 s-1 ). The interannual variability is 10%–20% of the time mean in both regions. By analyzing linear perturbations of mixing-length diffusivity expression, we show that the across-jet mixing in the upstream region is driven by variations in the mean flow, rather than eddy velocity. In the downstream region, both the mean flow and eddy velocity contribute to the temporal variability. Our results suggest that an eddy parameterization must take into account the along-jet variation of mixing, and within jets such diffusivities may be a simple function of jet strength.
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U2 - 10.1175/JPO-D-19-0042.1
DO - 10.1175/JPO-D-19-0042.1
M3 - Article
AN - SCOPUS:85076274406
VL - 49
SP - 2601
EP - 2614
JO - Journal of Physical Oceanography
JF - Journal of Physical Oceanography
SN - 0022-3670
IS - 10
ER -