@article{fdi:010091260,
  title = {{M}echanisms and intraseasonal variability in the {S}outh {V}ietnam {U}pwelling, {S}outh {C}hina {S}ea : the role of circulation, tides, and rivers},
  author = {{H}errmann, {M}arine and {D}uy, {T}. {T}. and {M}arsaleix, {P}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}ummer monsoon southwest wind induces the {S}outh {V}ietnam {U}pwelling ({SVU}) over four main areas along the southern and central {V}ietnamese coast: upwelling offshore of the {M}ekong shelf ({MKU}), along the southern and northern coasts ({SCU} and {NCU}), and offshore ({OFU}). {P}revious studies have highlighted the roles of wind and ocean intrinsic variability ({OIV}) in intraseasonal to interannual variability in the {SVU}. {T}he present study complements these results by examining the influence of tides and river discharges and investigates the physical mechanisms involved in {MKU} functioning.{MKU} is driven by non-chaotic processes, explaining its negligible intrinsic variability. {I}t is triggered first by the interactions of currents over marked topography. {T}he surface convergence of currents over the southwestern slope of the {M}ekong shelf induces a downwelling of the warm northeastward alongshore current. {I}t flows over the shelf and encounters a cold northwestward bottom current when reaching the northeastern slope. {T}he associated bottom convergence and surface divergence lead to an upwelling of cold water, which is entrained further north by the surface alongshore current.{T}ides strengthen this circulation-topography-induced {MKU} through two processes. {F}irst, tidal currents weaken the current over the shallow coastal shelf by enhancing the bottom friction. {T}his increases the horizontal velocity gradient and hence the resulting surface convergence and divergence and the associated downwelling and upwelling. {S}econd, they reinforce the surface cooling upstream and downstream of the shelf through lateral and vertical tidal mixing. {T}his tidal reinforcement explains 72 % of {MKU} intensity on average over the summer and is partly transmitted to {SCU} through advection. {T}ides do not significantly influence {OFU} and {NCU} intensity. {M}ekong waters slightly weaken {MKU} (by 9 % of the annual average) by strengthening the stratification but do not significantly influence {OFU}, {NCU}, and {SCU}. {L}ast, tides and rivers do not modify the chronology of upwelling in the four areas.},
  keywords = {{VIET} {NAM} ; {CHINE} {MER}},
  booktitle = {},
  journal = {{O}cean {S}cience},
  volume = {20},
  numero = {4},
  pages = {1013--1033},
  ISSN = {1812-0784},
  year = {2024},
  DOI = {10.5194/os-20-1013-2024},
  URL = {https://www.documentation.ird.fr/hor/fdi:010091260},
}