Spatial-temporal variability of submesoscale currents in the South China Sea
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摘要
Spatial and seasonal variabilities of submesoscale currents in the northeastern South China Sea are investigated by employing a numerical simulation with a horizontal resolution of 1 km. The results suggest that submesoscale currents are widespread in the surface mixed layer mainly due to the mixed layer instabilities and frontogenesis. In horizontal, submesoscale currents are generally more active in the north than those in the south, since that active eddies, especially cyclonic eddies, mainly occur in the northern area. Specifically, submesoscale currents are highly intensified in the east of Dongsha Island and south of Taiwan Island. In temporal sense, submesoscale currents are more active in winter than those in summer,since the mixed layer is thicker and more unstable in the winter. The parameterization developed by FoxKemper et al. is examined in terms of vertical velocity, and the results suggest that it could reproduce the vertical velocity if mixed layer instability dominates there. This study improves our understanding of the submesoscale dynamics in the South China Sea.
Spatial and seasonal variabilities of submesoscale currents in the northeastern South China Sea are investigated by employing a numerical simulation with a horizontal resolution of 1 km. The results suggest that submesoscale currents are widespread in the surface mixed layer mainly due to the mixed layer instabilities and frontogenesis. In horizontal, submesoscale currents are generally more active in the north than those in the south, since that active eddies, especially cyclonic eddies, mainly occur in the northern area. Specifically, submesoscale currents are highly intensified in the east of Dongsha Island and south of Taiwan Island. In temporal sense, submesoscale currents are more active in winter than those in summer,since the mixed layer is thicker and more unstable in the winter. The parameterization developed by FoxKemper et al. is examined in terms of vertical velocity, and the results suggest that it could reproduce the vertical velocity if mixed layer instability dominates there. This study improves our understanding of the submesoscale dynamics in the South China Sea.
Spatial and seasonal variabilities of submesoscale currents in the northeastern South China Sea are investigated by employing a numerical simulation with a horizontal resolution of 1 km. The results suggest that submesoscale currents are widespread in the surface mixed layer mainly due to the mixed layer instabilities and frontogenesis. In horizontal, submesoscale currents are generally more active in the north than those in the south, since that active eddies, especially cyclonic eddies, mainly occur in the northern area. Specifically, submesoscale currents are highly intensified in the east of Dongsha Island and south of Taiwan Island. In temporal sense, submesoscale currents are more active in winter than those in summer,since the mixed layer is thicker and more unstable in the winter. The parameterization developed by FoxKemper et al. is examined in terms of vertical velocity, and the results suggest that it could reproduce the vertical velocity if mixed layer instability dominates there. This study improves our understanding of the submesoscale dynamics in the South China Sea.
引文
Boccaletti G,Ferrari R,Fox-Kemper B.2007.Mixed layer instabilities and restratification.Journal of Physical Oceanography,37(9):2 228-2 250.
Brannigan L,Marshall D,Naveira-Garabato A,Nurser A.2015.The seasonal cycle of submesoscaleflows.Ocean Modelling,92:69-84.
Callies J,Ferrari R,Klymak J M,Gula J.2015.Seasonality in submesoscale turbulence.Nature Communications,6:6862.
Callies J,Ferrari R.2013.Interpreting energy and tracer spectra of upper-ocean turbulence in the submesoscale range(1-200 km).Journal of Physical Oceanography,43(11):2 456-2 474.
Callies J,Flierl G,Ferrari R,Fox-Kemper B.2016.The role of mixed-layer instabilities in submesoscale turbulence.Journal of Fluid Mechanics,788:5-41.
Capet X,McWilliams J C,Molemaker M J,Shchepetkin A F.2008a.Mesoscale to submesoscale transition in the California current system.Part I:flow structure,eddyflux,and observational tests.Journal of Physical Oceanography,38(1):29-43.
Capet X,McWilliams J C,Molemaker M J,Shchepetkin A F.2008b.Mesoscale to submesoscale transition in the California current system.Part II:frontal processes.Journal of Physical Oceanography,38(1):44-64.
Capet X,McWilliams J C,Molemaker M J,Shchepetkin A F.2008c.Mesoscale to submesoscale transition in the California current system.Part III:energy balance andflux.Journal of Physical Oceanography,38(10):2 256-2 269.
Charney J G.1971.Geostrophic turbulence.Journal of the Atmospheric Sciences,28(6):1 087-1 095.
D’Asaro E,Lee C,Rainville L,Harcourt R,Thomas L.2011.Enhanced turbulence and energy dissipation at ocean fronts.Science,332(6027):318-322.
Fox-Kemper B,Ferrari R,Hallberg R.2008.Parameterization of mixed layer eddies.Part I:theory and diagnosis.Journal of Physical Oceanography,38(6):1 145-1 165.
Gula J,Molemaker M J,McWilliams J C.2016.Topographic generation of submesoscale centrifugal instability and energy dissipation.Nature Communications,7:12 811.
Hoskins B J.1982.The mathematical theory of frontogenesis.Annual Review of Fluid Mechanics,14(1):131-151.
Ji C Z,Ye R J,Dong J H,Zhang Z W,Tian J W.2017.The simulation of submesoscale process at the periphery of a mesoscale eddy in the South China Sea.Periodical of Ocean University of China,47(1):1-6.(in Chinese with English abstract)
Liu Z Y,Lozovatsky I.2012.Upper pycnocline turbulence in the northern South China Sea.Chinese Science Bulletin,57(18):2 302-2 306.
Luo S H,Jing Z Y,Qi Y Q,Xie Q.2016.Numerical study on sub-mesoscale processes in the northern South China Sea.Journal of Tropical Oceanography,35(5):10-19.(in Chinese with English abstract)
Mahadevan A,Tandon A.2006.An analysis of mechanisms for submesoscale vertical motion at ocean fronts.Ocean Modelling,14(3-4):241-256.
Mahadevan A.2006.Modeling vertical motion at ocean fronts:Are nonhydrostatic ef fects relevant at submesoscales?Ocean Modelling,14(3-4):222-240.
Mason E,Molemaker J,Shchepetkin A F,Colas F,McWilliams J C,SangràP.2010.Procedures for oine grid nesting in regional ocean models.Ocean Modelling,35(1-2):1-15.
McGillicuddy D J,Robinson A R,Siegel D A,Jannasch H W,Johnson R,Dickey T D,McNeil J,Michaels A F,Knap AH.1998.Influence of mesoscale eddies on new production in the Sargasso Sea.Nature,394(6690):263-266.
McWilliams J C.2016.Submesoscale currents in the ocean.Proceedings of the Royal Society A:Mathematical,Physical and Engineering Science,472(2189):20160117.
Orlanski I.1976.A simple boundary condition for unbounded hyperbolicflows.Journal of Computational Physics,21(3):251-269.
Oschlies A.2008.Eddies and upper‐ocean nutrient supply.In:Hecht M,Hasumi H eds.Ocean Modeling in an Eddying Regime.Washington:Blackwell Publishing Ltd.,177:115-130.
Pollard R T,Regier L A.1992.Vorticity and vertical circulation at an ocean front.Journal of Physical Oceanography,22(6):609-625.
Qiu B,Chen S M,Klein P,Sasaki H,Sasai Y.2014.Seasonal mesoscale and submesoscale eddy variability along the North Pacific subtropical countercurrent.Journal of Physical Oceanography,44(12):3 079-3 098.
Ramp S R,Yang Y J,Bahr F L.2010.Characterizing the nonlinear internal wave climate in the northeastern South China Sea.Nonlinear Processes in Geophysics,17(5):481-498.
Roullet G,McWilliams J C,Capet X,Molemaker M J.2012.Properties of steady geostrophic turbulence with isopycnal outcropping.Journal of Physical Oceanography,42(1):18-38.
Sasaki H,Klein P,Qiu B,Sasai Y.2014.Impact of oceanicscale interactions on the seasonal modulation of ocean dynamics by the atmosphere.Nature Communications,5:5636.
Shang X D,Liang C R,Chen G Y.2017.Spatial distribution of turbulent mixing in the upper ocean of the South China Sea.Ocean Science,13(3):503-519.
Shchepetkin A F,McWilliams J C.2005.The regional oceanic modeling system(ROMS):a split-explicit,free-surface,topography-following-coordinate oceanic model.Ocean Modelling,9(4):347-404.
Taylor J R,Ferrari R.2011.Ocean fronts trigger high latitude phytoplankton blooms.Geophysical Research Letters,38(23):L23601.
Thomas L N,Tandon A,Mahadevan A.2008.Submesoscale processes and dynamics.In:Hecht M,Hasumi H eds.Ocean Modeling in an Eddying Regime.Washington:Blackwell Publishing Ltd.,177:17-38.
Thomas L N,Taylor J R,Ferrari R,Joyce T M.2013.Symmetric instability in the Gulf Stream.Deep Sea Research Part II:Topical Studies in Oceanography,91:96-110.
Uchida T,Abernathey R,Smith S.2017.Seasonality of eddy kinetic energy in an eddy permitting global climate model.Ocean Modelling,118:41-58.
Umlauf L,Burchard H.2003.A generic length-scale equation for geophysical turbulence models.Journal of Marine Research,61(2):235-265.
Wang G H,Su J L,Chu P C.2003.Mesoscale eddies in the South China Sea observed with altimeter data.Geophysical Research Letters,30(21):2121.
Xie X H,Shang X D,Chen G Y,Sun L.2009.Variations of diurnal and inertial spectral peaks near the bi-diurnal critical latitude.Geophysical Research Letters,36(2):L02606.
Yang Q X,Zhao W,Liang X F,Dong J H,Tian J W.2017.Elevated mixing in the periphery of mesoscale eddies in the South China Sea.Journal of Physical Oceanography,47(4):895-907.
Yang Q X,Zhao W,Liang X F,Tian J W.2016.Threedimensional distribution of turbulent mixing in the South China Sea.Journal of Physical Oceanography,46(3):769-788.
Zhang Z W,Tian J W,Qiu B,Zhao W,Chang P,Wu D X,Wan X Q.2016.Observed 3D structure,generation,and dissipation of oceanic mesoscale eddies in the South China Sea.Science Reports,6:24349.
Zheng Q A,Lin H,Meng J M,Hu X M,Song Y T,Zhang Y Z,Li C Y.2008.Sub‐mesoscale ocean vortex trains in the Luzon Strait.Journal of Geophysical Research:Oceans,113(C4):C04032.
Zhong Y S,Bracco A,Tian J W,Dong J H,Zhao W,Zhang ZW.2017.Observed and simulated submesoscale vertical pump of an anticyclonic eddy in the South China Sea.Science Reports,7:44011.
Zhong Y S,Bracco A.2013.Submesoscale impacts on horizontal and vertical transport in the Gulf of Mexico.Journal of Geophysical Research:Oceans,118(10):5 651-5 668.
Zhou C,Zhao W,Tian J W,Yang Q X,Qu T D.2014.Variability of the deep-water overflow in the Luzon Strait.Journal of Physical Oceanography,44(11):2 972-2 986.
Brannigan L,Marshall D,Naveira-Garabato A,Nurser A.2015.The seasonal cycle of submesoscaleflows.Ocean Modelling,92:69-84.
Callies J,Ferrari R,Klymak J M,Gula J.2015.Seasonality in submesoscale turbulence.Nature Communications,6:6862.
Callies J,Ferrari R.2013.Interpreting energy and tracer spectra of upper-ocean turbulence in the submesoscale range(1-200 km).Journal of Physical Oceanography,43(11):2 456-2 474.
Callies J,Flierl G,Ferrari R,Fox-Kemper B.2016.The role of mixed-layer instabilities in submesoscale turbulence.Journal of Fluid Mechanics,788:5-41.
Capet X,McWilliams J C,Molemaker M J,Shchepetkin A F.2008a.Mesoscale to submesoscale transition in the California current system.Part I:flow structure,eddyflux,and observational tests.Journal of Physical Oceanography,38(1):29-43.
Capet X,McWilliams J C,Molemaker M J,Shchepetkin A F.2008b.Mesoscale to submesoscale transition in the California current system.Part II:frontal processes.Journal of Physical Oceanography,38(1):44-64.
Capet X,McWilliams J C,Molemaker M J,Shchepetkin A F.2008c.Mesoscale to submesoscale transition in the California current system.Part III:energy balance andflux.Journal of Physical Oceanography,38(10):2 256-2 269.
Charney J G.1971.Geostrophic turbulence.Journal of the Atmospheric Sciences,28(6):1 087-1 095.
D’Asaro E,Lee C,Rainville L,Harcourt R,Thomas L.2011.Enhanced turbulence and energy dissipation at ocean fronts.Science,332(6027):318-322.
Fox-Kemper B,Ferrari R,Hallberg R.2008.Parameterization of mixed layer eddies.Part I:theory and diagnosis.Journal of Physical Oceanography,38(6):1 145-1 165.
Gula J,Molemaker M J,McWilliams J C.2016.Topographic generation of submesoscale centrifugal instability and energy dissipation.Nature Communications,7:12 811.
Hoskins B J.1982.The mathematical theory of frontogenesis.Annual Review of Fluid Mechanics,14(1):131-151.
Ji C Z,Ye R J,Dong J H,Zhang Z W,Tian J W.2017.The simulation of submesoscale process at the periphery of a mesoscale eddy in the South China Sea.Periodical of Ocean University of China,47(1):1-6.(in Chinese with English abstract)
Liu Z Y,Lozovatsky I.2012.Upper pycnocline turbulence in the northern South China Sea.Chinese Science Bulletin,57(18):2 302-2 306.
Luo S H,Jing Z Y,Qi Y Q,Xie Q.2016.Numerical study on sub-mesoscale processes in the northern South China Sea.Journal of Tropical Oceanography,35(5):10-19.(in Chinese with English abstract)
Mahadevan A,Tandon A.2006.An analysis of mechanisms for submesoscale vertical motion at ocean fronts.Ocean Modelling,14(3-4):241-256.
Mahadevan A.2006.Modeling vertical motion at ocean fronts:Are nonhydrostatic ef fects relevant at submesoscales?Ocean Modelling,14(3-4):222-240.
Mason E,Molemaker J,Shchepetkin A F,Colas F,McWilliams J C,SangràP.2010.Procedures for oine grid nesting in regional ocean models.Ocean Modelling,35(1-2):1-15.
McGillicuddy D J,Robinson A R,Siegel D A,Jannasch H W,Johnson R,Dickey T D,McNeil J,Michaels A F,Knap AH.1998.Influence of mesoscale eddies on new production in the Sargasso Sea.Nature,394(6690):263-266.
McWilliams J C.2016.Submesoscale currents in the ocean.Proceedings of the Royal Society A:Mathematical,Physical and Engineering Science,472(2189):20160117.
Orlanski I.1976.A simple boundary condition for unbounded hyperbolicflows.Journal of Computational Physics,21(3):251-269.
Oschlies A.2008.Eddies and upper‐ocean nutrient supply.In:Hecht M,Hasumi H eds.Ocean Modeling in an Eddying Regime.Washington:Blackwell Publishing Ltd.,177:115-130.
Pollard R T,Regier L A.1992.Vorticity and vertical circulation at an ocean front.Journal of Physical Oceanography,22(6):609-625.
Qiu B,Chen S M,Klein P,Sasaki H,Sasai Y.2014.Seasonal mesoscale and submesoscale eddy variability along the North Pacific subtropical countercurrent.Journal of Physical Oceanography,44(12):3 079-3 098.
Ramp S R,Yang Y J,Bahr F L.2010.Characterizing the nonlinear internal wave climate in the northeastern South China Sea.Nonlinear Processes in Geophysics,17(5):481-498.
Roullet G,McWilliams J C,Capet X,Molemaker M J.2012.Properties of steady geostrophic turbulence with isopycnal outcropping.Journal of Physical Oceanography,42(1):18-38.
Sasaki H,Klein P,Qiu B,Sasai Y.2014.Impact of oceanicscale interactions on the seasonal modulation of ocean dynamics by the atmosphere.Nature Communications,5:5636.
Shang X D,Liang C R,Chen G Y.2017.Spatial distribution of turbulent mixing in the upper ocean of the South China Sea.Ocean Science,13(3):503-519.
Shchepetkin A F,McWilliams J C.2005.The regional oceanic modeling system(ROMS):a split-explicit,free-surface,topography-following-coordinate oceanic model.Ocean Modelling,9(4):347-404.
Taylor J R,Ferrari R.2011.Ocean fronts trigger high latitude phytoplankton blooms.Geophysical Research Letters,38(23):L23601.
Thomas L N,Tandon A,Mahadevan A.2008.Submesoscale processes and dynamics.In:Hecht M,Hasumi H eds.Ocean Modeling in an Eddying Regime.Washington:Blackwell Publishing Ltd.,177:17-38.
Thomas L N,Taylor J R,Ferrari R,Joyce T M.2013.Symmetric instability in the Gulf Stream.Deep Sea Research Part II:Topical Studies in Oceanography,91:96-110.
Uchida T,Abernathey R,Smith S.2017.Seasonality of eddy kinetic energy in an eddy permitting global climate model.Ocean Modelling,118:41-58.
Umlauf L,Burchard H.2003.A generic length-scale equation for geophysical turbulence models.Journal of Marine Research,61(2):235-265.
Wang G H,Su J L,Chu P C.2003.Mesoscale eddies in the South China Sea observed with altimeter data.Geophysical Research Letters,30(21):2121.
Xie X H,Shang X D,Chen G Y,Sun L.2009.Variations of diurnal and inertial spectral peaks near the bi-diurnal critical latitude.Geophysical Research Letters,36(2):L02606.
Yang Q X,Zhao W,Liang X F,Dong J H,Tian J W.2017.Elevated mixing in the periphery of mesoscale eddies in the South China Sea.Journal of Physical Oceanography,47(4):895-907.
Yang Q X,Zhao W,Liang X F,Tian J W.2016.Threedimensional distribution of turbulent mixing in the South China Sea.Journal of Physical Oceanography,46(3):769-788.
Zhang Z W,Tian J W,Qiu B,Zhao W,Chang P,Wu D X,Wan X Q.2016.Observed 3D structure,generation,and dissipation of oceanic mesoscale eddies in the South China Sea.Science Reports,6:24349.
Zheng Q A,Lin H,Meng J M,Hu X M,Song Y T,Zhang Y Z,Li C Y.2008.Sub‐mesoscale ocean vortex trains in the Luzon Strait.Journal of Geophysical Research:Oceans,113(C4):C04032.
Zhong Y S,Bracco A,Tian J W,Dong J H,Zhao W,Zhang ZW.2017.Observed and simulated submesoscale vertical pump of an anticyclonic eddy in the South China Sea.Science Reports,7:44011.
Zhong Y S,Bracco A.2013.Submesoscale impacts on horizontal and vertical transport in the Gulf of Mexico.Journal of Geophysical Research:Oceans,118(10):5 651-5 668.
Zhou C,Zhao W,Tian J W,Yang Q X,Qu T D.2014.Variability of the deep-water overflow in the Luzon Strait.Journal of Physical Oceanography,44(11):2 972-2 986.