@article{fdi:010093499,
  title = {{I}nadequacies in the representation of sub-seasonal phytoplankton dynamics in {E}arth system models},
  author = {{K}eerthi, {M}. {G}. and {A}umont, {O}livier and {K}wiatkowski, {L}. and {L}evy, {M}arina},
  editor = {},
  language = {{ENG}},
  abstract = {{S}ub-seasonal phytoplankton dynamics on timescales between 8 d and 3 months significantly contribute to annual fluctuations, making it essential to accurately represent this variability in ocean models to avoid distorting long-term trends. {T}his study assesses the capability of {E}arth system models ({ESM}s) participating in the {C}oupled {M}odel {I}ntercomparison {P}roject {P}hase 6 ({CMIP}6) to reproduce sub-seasonal surface ocean phytoplankton variations observed in ocean colour satellite data. {O}ur findings reveal that, unlike sea surface temperature, all models struggle to accurately reproduce the total surface ocean phytoplankton variance and its decomposition across sub-seasonal, seasonal and multi-annual timescales. {O}ver the historical period, some models strongly overestimate sub-seasonal variance and exaggerate its role in annual fluctuations, while others underestimate it. {O}ur analysis suggests that underestimation of sub-seasonal variance is likely a consequence of the coarse horizontal resolution of {CMIP}6 models, which is insufficient to resolve mesoscale processes - a limitation potentially alleviated with higher-resolution models. {C}onversely, we suggest that the overestimation of sub-seasonal variance is potentially the consequence of intrinsic oscillations such as predator-prey oscillations in certain biogeochemical models. {ESM}s consistently show a reduction in variance at sub-seasonal and seasonal timescales during the 21st century under high-emission scenarios. {T}he poor capability of {CMIP}6 models at simulating sub-seasonal chlorophyll dynamics casts doubt on their projections at these temporal scales and multi-annual timescales. {T}his study underscores the need to enhance spatial resolution and constrain intrinsic biogeochemical oscillations to improve projections of ocean phytoplankton dynamics.},
  keywords = {{MONDE}},
  booktitle = {},
  journal = {{B}iogeosciences},
  volume = {22},
  numero = {9},
  pages = {2163--2180},
  ISSN = {1726-4170},
  year = {2025},
  DOI = {10.5194/bg-22-2163-2025},
  URL = {https://www.documentation.ird.fr/hor/fdi:010093499},
}