@article{fdi:010073734,
  title = {{S}ubseasonal coastal-trapped wave propagations in the {S}outheastern {P}acific and {A}tlantic {O}ceans : 2. {W}ave characteristics and connection with the equatorial variability},
  author = {{I}llig, {S}erena and {B}achelery, {M}. {L}. and {C}adier, {E}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}he objective of this study is to compare the characteristics of the oceanic teleconnection with the linear equatorial dynamics of two upwelling systems along the southwestern {S}outh {A}merican and {A}frican continents at subseasonal time scales (<120 days). {A}ltimetric data analysis shows that the coastal variability remains coherent with the equatorial signal until 27 degrees {S} in the southeastern {P}acific ({SEP}), while in the southeastern {A}tlantic ({SEA}) it fades out south of 12 degrees {S}. {T}o explain this striking difference, our methodology is based on the experimentation with twin regional model configurations of the {SEP} and {SEA} {O}ceans. {T}he estimation of free {C}oastal-{T}rapped {W}aves ({CTW}s) modal structures and associated contribution to coastal variability allows inferring and comparing the characteristics of each {CTW} mode in the two systems; namely, their forcings, amplitude, dissipation rate, and scattering. {R}esults show that the {P}acific subseasonal equatorial forcing is only 20% larger than in the {A}tlantic, but important differences in the relative contribution of each baroclinic mode are reported. {T}he first baroclinic mode dominates the eastern equatorial {P}acific variability, while in the eastern equatorial {A}tlantic, the second mode is the most energetic. {T}his leads to a drastic increase in the dissipation and scattering of the remotely forced {CTW} in the {SEA} sector, compared to the coastal {SEP}. {C}oncomitantly, south of 15 degrees {S}, the subseasonal coastal wind stress forcing is substantially more energetic in the {SEA} and participates in breaking the link between the equatorial forcing and the coastal variability. {O}ur results are consistent with the solutions of a simple multimode {CTW} model. {P}lain {L}anguage {S}ummary {T}he {H}umboldt and the {B}enguela upwelling systems are connected to the equatorial variability. {P}art of the incoming eastward equatorial wave energy is transmitted southward along the {S}outh {A}merican and {A}frican coasts as {C}oastal-{T}rapped {W}aves, where they imprint on the ecosystem variability. {A}t subseasonal time scales (<120 days), altimetry reveals that the coastal variability remains coherent with the equatorial signal until 27 degrees {S} in the southeastern {P}acific, while in the {A}tlantic counterpart it fades out south of 12 degrees {S}. {T}o explain this striking difference, we compare the characteristics of coastal waves between the two systems: their forcing at the equator, their dissipation and scattering along their propagation, and the energization by the coastal wind stress. {W}e use a variety of ocean models of different complexity ranging from regional general circulation models to simple linear coastal models. {R}esults show that the difference between the two systems regarding the connection with the equatorial variability can be attributed to the distinct characteristics of their equatorial forcing. {T}he latter favors fast and weakly dissipative coastal wave in the {H}umboldt. {O}ff southwestern {A}frica, the equatorially-forced coastal-trapped waves dissipate at approximate to 13 degrees {S} and the subseasonal coastal wind stress forcing which is energetic south of 15 degrees {S}, participates in breaking the link between the equatorial and coastal variabilities.},
  keywords = {{C}oastal {T}rapped {W}aves ; {E}astern {B}oundary {U}pwelling {S}ystems ; model experimentation ; subseasonal variability ; linear coastal model ; altimetry ; {PACIFIQUE} {SUD} {EST} ; {ATLANTIQUE} {SUD} {EST} ; {ZONE} {EQUATORIALE}},
  booktitle = {},
  journal = {{J}ournal of {G}eophysical {R}esearch : {O}ceans},
  volume = {123},
  numero = {6},
  pages = {3942--3961},
  ISSN = {2169-9275},
  year = {2018},
  DOI = {10.1029/2017jc013540},
  URL = {https://www.documentation.ird.fr/hor/fdi:010073734},
}