@article{fdi:010063997,
  title = {{S}patial trend patterns in the {P}acific {O}cean sea level during the altimetry era : the contribution of thermocline depth change and internal climate variability},
  author = {{P}alanisamy, {H}. and {C}azenave, {A}. and {D}elcroix, {T}hierry and {M}eyssignac, {B}.},
  editor = {},
  language = {{ENG}},
  abstract = {{T}his study investigates the spatial trend patterns and variability of observed sea level and upper ocean thermal structure in the {P}acific {O}cean during the altimetry era (1993-2012), and the role of thermocline depth changes. {T}he observed sea level trend pattern in this region results from the superposition of two main signals: (1) a strong broad-scale {V}-shaped positive trend anomaly extending to mid-latitudes in the central {P}acific and (2) another very strong positive trend anomaly located in the western tropical {P}acific within about 120{A} degrees {E}-160{A} degrees {E} and 20{A} degrees {S}-20{A} degrees {N} latitude. {I}n this study, we focus on the tropical {P}acific (20{A} degrees {N}-20{A} degrees {S}) where the strongest trends in sea level are observed. {B}y making use of in situ observational data, we study the impact of thermocline depth changes on steric sea level between the surface and 700 m and its relation with the altimetry-based observed sea level changes. {T}his is done by calculating the time-varying thermocline depth (using the 20 {A} degrees {C} isotherm depth as a proxy) and estimating the sea level trend patterns of the thermocline-attributed individual steric components. {W}e show that it is essentially the vertical movement of the thermocline that governs most of the observed sea level changes and trends in the tropical {P}acific. {F}urthermore, we also show that in the equatorial band, the changes in the upper ocean thermal structure are in direct response to the zonal wind stress. {A}way from the equatorial band (say, within 5{A} degrees-15{A} degrees latitude), the changes in the upper ocean thermal structure are consistent with the wind stress-generated {R}ossby waves. {W}e also estimate the contribution of the {I}nterdecadal {P}acific {O}scillation ({IPO}) on the vertical thermal structure of the tropical {P}acific {O}cean. {R}emoving the {IPO} contribution to the upper layer steric sea level provides a non-negligible residual pattern, suggesting that {IPO}-related internal ocean variability alone cannot account for the observed trend patterns in the {P}acific sea level. {I}t is likely that the residual signal may also reflect non-linear interactions between different natural modes like {E}l {N}io {S}outhern {O}scillation ({ENSO}), {IPO}, etc.},
  keywords = {{T}ropical {P}acific ; {W}ind-driven thermocline depth changes ; {U}pper layer ; steric sea level contribution ; {I}nternal climate variability ; {I}nterdecadal {P}acific {O}scillation ; {PACIFIQUE}},
  booktitle = {},
  journal = {{O}cean {D}ynamics},
  volume = {65},
  numero = {3},
  pages = {341--356},
  ISSN = {1616-7341},
  year = {2015},
  DOI = {10.1007/s10236-014-0805-7},
  URL = {https://www.documentation.ird.fr/hor/fdi:010063997},
}