Air-Sea interaction over the Gulf Stream in an ensemble of HighResMIP present climate simulations

• Published in: Climate Dynamics
• Main Authors: Bellucci, Alessio, Athanasiadis, Panos J., Scoccimarro, Enrico, Ruggieri, Paolo, Gualdi, Silvio, Fedele, Giusy, Haarsma, Reindert J., García Serrano, Javier, Castrillo, Miguel, Putrahasan, D., Sanchez-Gomez, Emilia, Moine, Marie-Pierre, Roberts, Christopher D., Roberts, Michael J., Seddon, J, Vidale, Pier Luigi
• Other Authors: Barcelona Supercomputing Center
• Format: Article in Journal/Newspaper
• Language: English
• Published: Springer Link 2021
• Subjects: Àrees temàtiques de la UPC::Enginyeria agroalimentària::Ciències de la terra i de la vida; Ocean-atmosphere interaction; Gulf Stream; HighResMIP; Climate simulation; Air-sea interaction; Climate models; Simulacio per ordinador; North Atlantic
• Online Access: http://hdl.handle.net/2117/340396; https://doi.org/10.1007/s00382-020-05573-z

A dominant paradigm for mid-latitude air-sea interaction identifies the synoptic-scale atmospheric “noise” as the main driver for the observed ocean surface variability. While this conceptual model successfully holds over most of the mid-latitude ocean surface, its soundness over frontal zones (including western boundary currents; WBC) characterized by intense mesoscale activity, has been questioned in a number of studies suggesting a driving role for the small scale ocean dynamics (mesoscale oceanic eddies) in the modulation of air-sea interaction. In this context, climate models provide a powerful experimental device to inspect the emerging scale-dependent nature of mid-latitude air-sea interaction. This study assesses the impact of model resolution on the representation of air-sea interaction over the Gulf Stream region, in a multi-model ensemble of present-climate simulations performed using a common experimental design. Lead-lag correlation and covariance patterns between sea surface temperature (SST) and turbulent heat flux (THF) are diagnosed to identify the leading regimes of air-sea interaction in a region encompassing both the Gulf Stream system and the North Atlantic subtropical basin. Based on these statistical metrics it is found that coupled models based on “laminar” (eddy-parameterised) and eddy-permitting oceans are able to discriminate between an ocean-driven regime, dominating the region controlled by the Gulf Stream dynamics, and an atmosphere-driven regime, typical of the open ocean regions. However, the increase of model resolution leads to a better representation of SST and THF cross-covariance patterns and functional forms, and the major improvements can be largely ascribed to a refinement of the oceanic model component. The authors of this study wish to thank two reviewers for their many insightful comments. AB, PA, ES, RH, JG-S, DP, ESG, MJR, CR, JS, PV acknowledge PRIMAVERA funding received from the European Commission under Grant Agreement 641727 of the Horizon 2020 research programme. JG-S was additionally supported by the Spanish ‘Ramón y Cajal’ programme (RYC-2016-21181). The authors declare that they have no conflict of interest. The datasets used in this work are cited in this manuscript with appropriate doi’s in publicly available archives. Peer Reviewed Postprint (published version)