@article{fdi:010064207,
  title = {{I}mpact of sea level assimilation on {ENSO} initialization and prediction : the role of the sea level zonal tilt and zonal mean},
  author = {{T}hual, {S}. and {A}youb, {N}. and {D}ewitte, {B}oris},
  editor = {},
  language = {{ENG}},
  abstract = {{A}t present, most models forecasting the {E}l {N}ino-{S}outhern {O}scillation ({ENSO}) use data assimilation, which constrains models physics using available observations. {I}n this article, an {ENSO} model of intermediate complexity is constrained by sea level observations: sea level from the {S}imple {O}cean {D}ata {A}ssimilation ({SODA}) reanalysis is assimilated in the model forced by {SODA} winds, using an ensemble {K}alman filter. {I}n addition, retrospective {ENSO} forecasts over the period 1958-2007 are computed. {T}he assimilation of sea level observations slightly improves the model's predictive skill, which is due to the correction of the recharge discharge process simulated by the model. {T}o assess this, two indices relevant to the {ENSO} recharge discharge theory are considered: the zonal tilt and zonal mean of sea level in the equatorial {P}acific. {T}he assimilation of those two observed indices alone leads to results that are qualitatively similar to the assimilation of full maps of sea level observations. {T}his partly results from the fact that the leading statistical modes of the model errors on sea level have a zonal tilt and zonal mean structure. {T}he data assimilation corrects in particular a too weak amplitude of the zonal mean sea level and its associated subsurface variability in the model. {T}he authors suggest that insight on the role of the recharge-discharge process in other models could be gained by comparing the assimilation of full maps of sea level observations with the assimilation of the two indices of sea level.},
  keywords = {{PACIFIQUE}},
  booktitle = {},
  journal = {{M}onthly {W}eather {R}eview},
  volume = {143},
  numero = {5},
  pages = {1895--1906},
  ISSN = {0027-0644},
  year = {2015},
  DOI = {10.1175/mwr-d-13-00352.1},
  URL = {https://www.documentation.ird.fr/hor/fdi:010064207},
}