Fast Warming of the Surface Ocean Under a Climatological Scenario

• Published in: Geophysical Research Letters
• Main Authors: Jamet, Q., Dewar, W., K, Wienders, N., Deremble, B.
• Other Authors: Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Florida State University Tallahassee (FSU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2019
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; North Atlantic
• Online Access: https://hal.science/hal-02410290; https://hal.science/hal-02410290/document; https://hal.science/hal-02410290/file/clim_wind_v03.pdf; https://doi.org/10.1029/2019GL082336

International audience Key Points: 6 • Weakly varying climatological winds reduce upper ocean vertical mixing, affect-7 ing the redistribution of air-sea fluxes 8 • Coupled to an atmospheric boundary layer, the modeled ocean response to clima-9 tological winds is to warm up considerably at the surface 10 • Results illustrate the pivotal improvements in air-sea interactions achieved by driv-11 ing an ocean model with an atmospheric boundary layer 12 Abstract 13 We examine various strategies for forcing ocean-only models, including an atmospheric 14 boundary layer model. This surface forcing allows air-sea exchanges to affect atmospheric 15 temperature and relative humidity, thus removing the assumption of an infinite atmo-16 spheric heat capacity associated with the prescription of these variables. When exposed 17 to climatological winds, the simulated North Atlantic oceanic temperature warms con-18 siderably at the surface as compared to a model with full atmospheric variability. This 19 warming is mainly explained by a weakened upper ocean vertical mixing in response to 20 the weakly varying climatological winds. Specifying the atmospheric temperatures in-21 hibits this warming, but depends on the unrealistic large atmospheric heat capacity. We 22 thus interpret the simulated warmer ocean as a more physically consistent ocean response. 23 We conclude the use of an atmospheric boundary layer model provides many benefits 24 for ocean only modeling, although a 'normal' year strategy is required for maintaining 25 high frequency winds. 26