Coupling NEMO global ocean with hemispheric Arctic and Antarctic ice models

• Main Authors: Maisonnave, E, Bourdallé-Badie, R
• Other Authors: Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), Mercator Océan, Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Service hydrographique et océanographique de la Marine-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Cerfacs, Mercator ocean international
• Format: Report
• Language: English
• Published: HAL CCSD 2022
• Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; Arctic; Antarctic; North Pole; Antarc*; Antarctique*; Arctique*; Orca; Sea ice
• Online Access: https://hal.science/hal-03597235; https://hal.science/hal-03597235/document; https://hal.science/hal-03597235/file/support_esiwace.pdf

Two new NEMO-SAS (stand alone surface module) configurations are derived from a global ORCA grid. A FORTRAN tool is developed to transform the ORCA input files and define the OASIS weights & addresses to map fluxes and surface variables between one global and two hemispheric grids. A tri-component coupled system is set up, including an ocean on the ORCA2 global grid and two hemispheric NEMO-SAS with SI3 sea-ice. Removing North Pole folding communications in ice model helps to improve computing performance, since our ORCA2 coupled configuration is twice faster and two times cheaper than its single executable counterpart. The North Pole folding free hemispheric grid discretisation simplifies the coding of the future neXtSIM model, while relying on the same grid points than the ocean, thus avoiding inaccurate interpolation between ice and ocean grids