@article{fdi:010073786,
  title = {{T}he impacts of oceanic deep temperature perturbations in the {N}orth {A}tlantic on decadal climate variability and predictability},
  author = {{G}erme, {A}. and {S}evellec, {F}. and {M}ignot, {J}uliette and {F}edorov, {A}. and {N}guyen, {S}. and {S}wingedouw, {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{D}ecadal climate predictability in the {N}orth {A}tlantic is largely related to ocean low frequency variability, whose sensitivity to initial conditions is not very well understood. {R}ecently, three-dimensional oceanic temperature anomalies optimally perturbing the {N}orth {A}tlantic {M}ean {T}emperature ({NAMT}) have been computed via an optimization procedure using a linear adjoint to a realistic ocean general circulation model. {T}he spatial pattern of the identified perturbations, localized in the {N}orth {A}tlantic, has the largest magnitude between 1000 and 4000 m depth. {I}n the present study, the impacts of these perturbations on {NAMT}, on the {A}tlantic meridional overturning circulation ({AMOC}), and on climate in general are investigated in a global coupled model that uses the same ocean model as was used to compute the three-dimensional optimal perturbations. {I}n the coupled model, these perturbations induce {AMOC} and {NAMT} anomalies peaking after 5 and 10 years, respectively, generally consistent with the ocean-only linear predictions. {T}o further understand their impact, their magnitude was varied in a broad range. {F}or initial perturbations with a magnitude comparable to the internal variability of the coupled model, the model response exhibits a strong signature in sea surface temperature and precipitation over {N}orth {A}merica and the {S}ahel region. {T}he existence and impacts of these ocean perturbations have important implications for decadal prediction: they can be seen either as a source of predictability or uncertainty, depending on whether the current observing system can detect them or not. {I}n fact, comparing the magnitude of the imposed perturbations with the uncertainty of available ocean observations such as {A}rgo data or ocean state estimates suggests that only the largest perturbations used in this study could be detectable. {T}his highlights the importance for decadal climate prediction of accurate ocean density initialisation in the {N}orth {A}tlantic at intermediate and greater depths.},
  keywords = {{D}ecadal climate predictability ; {I}nitial condition uncertainties ; {L}inear ; optimal perturbations ; {N}orth {A}tlantic variability ; {A}tlantic meridional ; overturning circulation ; {IPSL}-{CM}5{A} ; {ATLANTIQUE} {NORD}},
  booktitle = {},
  journal = {{C}limate {D}ynamics},
  volume = {51},
  numero = {5-6},
  pages = {2341--2357},
  ISSN = {0930-7575},
  year = {2018},
  DOI = {10.1007/s00382-017-4016-z},
  URL = {https://www.documentation.ird.fr/hor/fdi:010073786},
}