Seasonality in Transition Scale from Balanced to Unbalanced Motions in the World Ocean

AbstractThe transition scale Lt from balanced geostrophic motions to unbalanced wave motions, including near-inertial flows, internal tides, and inertia–gravity wave continuum, is explored using the output from a global 1/48° horizontal resolution Massachusetts Institute of Technology general circulation model (MITgcm) simulation. Defined as the wavelength with equal balanced and unbalanced motion kinetic energy (KE) spectral density, Lt is detected to be geographically highly inhomogeneous: it falls below 40 km in the western boundary current and Antarctic Circumpolar Current regions, increases to 40–100 km in the interior subtropical and subpolar gyres, and exceeds, in general, 200 km in the tropical oceans. With the exception of the Pacific and Indian sectors of the Southern Ocean, the seasonal KE fluctuations of the surface balanced and unbalanced motions are out of phase because of the occurrence of mixed layer instability in winter and trapping of unbalanced motion KE in shallow mixed layer in summe...

[1]  T. Özgökmen,et al.  Seasonality of the submesoscale dynamics in the Gulf Stream region , 2013, Ocean Dynamics.

[2]  E. D’Asaro.  Mixed layer velocities induced by internal waves , 1978 .

[3]  C. Wunsch,et al.  Ocean Circulation Kinetic Energy: Reservoirs, Sources, and Sinks , 2009 .

[4]  H. Simmons,et al.  Near-Inertial Internal Gravity Waves in the Ocean. , 2016, Annual review of marine science.

[5]  Jonathan Gula,et al.  Seasonality in submesoscale turbulence , 2015, Nature Communications.

[6]  Gilles Reverdin,et al.  Global high-resolution mapping of ocean circulation from TOPEX/Poseidon and ERS-1 and -2 , 2000 .

[7]  Raffaele Ferrari,et al.  Interpreting Energy and Tracer Spectra of Upper-Ocean Turbulence in the Submesoscale Range (1–200 km) , 2013 .

[8]  J. McWilliams,et al.  Mesoscale to Submesoscale Transition in the California Current System. Part I: Flow Structure, Eddy Flux, and Observational Tests , 2008 .

[9]  B. Qiu,et al.  Submesoscale transition from geostrophic flows to internal waves in the northwestern Pacific upper ocean , 2017, Nature Communications.

[10]  Christian E. Buckingham,et al.  Open-Ocean Submesoscale Motions: A Full Seasonal Cycle of Mixed Layer Instabilities from Gliders , 2016 .

[11]  Patrice Klein,et al.  Dynamics of the Upper Oceanic Layers in Terms of Surface Quasigeostrophy Theory , 2006 .

[12]  Dimitris Menemenlis,et al.  Spectral decomposition of internal gravity wave sea surface height in global models , 2017 .

[13]  Daniele Iudicone,et al.  Mixed layer depth over the global ocean: An examination of profile data and a profile-based climatology , 2004 .

[14]  R. Ray,et al.  M2 Internal Tides and Their Observed Wavenumber Spectra from Satellite Altimetry , 2016 .

[15]  Christian E. Buckingham,et al.  Seasonality of submesoscale flows in the ocean surface boundary layer , 2016 .

[16]  Lee-Lueng Fu,et al.  Eddy dynamics from satellite altimetry , 2010 .

[17]  D. Chelton,et al.  Global observations of nonlinear mesoscale eddies , 2011 .

[18]  A. Wallcraft,et al.  Inferring dynamics from the wavenumber spectra of an eddying global ocean model with embedded tides , 2012 .

[19]  Dimitris Menemenlis,et al.  An Observing System Simulation Experiment for the Calibration and Validation of the Surface Water Ocean Topography Sea Surface Height Measurement Using In Situ Platforms , 2017 .

[20]  T. Lee,et al.  ECCO2: High Resolution Global Ocean and Sea Ice Data Synthesis , 2008 .

[21]  L. Perelman,et al.  A finite-volume, incompressible Navier Stokes model for studies of the ocean on parallel computers , 1997 .

[22]  D. Menemenlis,et al.  Seasonality of submesoscale dynamics in the Kuroshio Extension , 2016 .

[23]  Patrice Klein,et al.  Oceanic Restratification Forced by Surface Frontogenesis , 2006 .

[24]  G. Mitchum,et al.  Surface manifestation of internal tides generated near Hawaii , 1996 .

[25]  Alan J. Wallcraft,et al.  Frequency content of sea surface height variability from internal gravity waves to mesoscale eddies , 2017 .

[26]  Bo Qiu,et al.  Impact of oceanic-scale interactions on the seasonal modulation of ocean dynamics by the atmosphere , 2014, Nature Communications.

[27]  Yan Du,et al.  Interannual and interdecadal variability of the North Equatorial Countercurrent in the Western Pacific , 2016 .

[28]  L. Rainville,et al.  Global Observations of Open-Ocean Mode-1 M2Internal Tides , 2016 .

[29]  Dimitris Menemenlis,et al.  Mesoscale to submesoscale wavenumber spectra in Drake Passage , 2016 .

[30]  E. Zaron.  Mapping the Nonstationary Internal Tide with Satellite Altimetry , 2017 .

[31]  R. Ray,et al.  Non‐stationary internal tides observed with satellite altimetry , 2011 .

[32]  Lee-Lueng Fu,et al.  Reconstructability of Three-Dimensional Upper-Ocean Circulation from SWOT Sea Surface Height Measurements , 2016 .

[33]  J. Richman,et al.  How stationary are the internal tides in a high‐resolution global ocean circulation model? , 2014 .

[34]  A. E. Gill.  Atmosphere-Ocean Dynamics , 1982 .

[35]  Patrice Klein,et al.  Upper Ocean Turbulence from High-Resolution 3D Simulations , 2008 .

[36]  D. Stammer.  Global Characteristics of Ocean Variability Estimated from Regional TOPEX/POSEIDON Altimeter Measurements , 1997 .

[37]  Rosemary Morrow,et al.  Recent advances in observing mesoscale ocean dynamics with satellite altimetry , 2012 .

[38]  Lee-Lueng Fu,et al.  On the Transition from Profile Altimeter to Swath Altimeter for Observing Global Ocean Surface Topography , 2014 .

[39]  R. Ferrari,et al.  Wave–vortex decomposition of one-dimensional ship-track data , 2014, Journal of Fluid Mechanics.

[40]  Gilles Larnicol,et al.  New CNES‐CLS09 global mean dynamic topography computed from the combination of GRACE data, altimetry, and in situ measurements , 2011 .

[41]  Y. Sasai,et al.  Seasonal Mesoscale and Submesoscale Eddy Variability along the North Pacific Subtropical Countercurrent , 2014 .

[42]  B. Qiu,et al.  Interannual variability in the mid- and low-latitude western North Pacific , 1992 .

[43]  James C. McWilliams,et al.  Submesoscale currents in the ocean , 2016, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.