title: Thermodynamic controls of the Atlantic Niño.
abstract: Prevailing theories on the equatorial Atlantic Niño are based on the dynamical interaction between atmosphere and ocean. However, dynamical coupled ocean-atmosphere models poorly simulate and predict equatorial Atlantic climate variability. Here we use multi-model numerical experiments to show that thermodynamic feedbacks excited by stochastic atmospheric perturbations can generate Atlantic Niño s.d. of ∼0.28±0.07 K, explaining ∼68±23% of the observed interannual variability. Thus, in state-of-the-art coupled models, Atlantic Niño variability strongly depends on the thermodynamic component (R(2)=0.92). Coupled dynamics acts to improve the characteristic Niño-like spatial structure but not necessarily the variance. Perturbations of the equatorial Atlantic trade winds (∼±1.53 m s(-1)) can drive changes in surface latent heat flux (∼±14.35 W m(-2)) and thus in surface temperature consistent with a first-order autoregressive process. By challenging the dynamical paradigm of equatorial Atlantic variability, our findings suggest that the current theories on its modelling and predictability must be revised.
authors.affiliation: Department of Geography, University of Nigeria, Nsukka 410001, Nigeria.
authors.forename: Hyacinth C
authors.initials: HC
authors.lastname: Nnamchi
authors.affiliation: College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China.|Joint Center for Global Change Studies, Beijing 100875, China.
authors.forename: Jianping
authors.initials: J
authors.lastname: Li
authors.affiliation: Earth System Physics Section, Abdus Salam International Centre for Theoretical Physics, Strada Costiera, 11, Trieste 34151, Italy.
authors.forename: Fred
authors.initials: F
authors.lastname: Kucharski
authors.affiliation: School of Earth and Environmental Sciences, Seoul National University, Seoul 151-742, South Korea.
authors.forename: In-Sik
authors.initials: IS
authors.lastname: Kang
authors.affiliation: Geophysical Institute, University of Bergen and Bjerknes Centre for Climate Research, Allégaten 70, 5007 Bergen, Norway.
authors.forename: Noel S
authors.initials: NS
authors.lastname: Keenlyside
authors.affiliation: Department of Oceanography, Texas A&M University, College Station, Texas 77843-3160, USA.|Collaborative Innovation Center of Marine Science and Technology, Ocean University of China, Qingdao 266100, China.
authors.forename: Ping
authors.initials: P
authors.lastname: Chang
authors.affiliation: Earth System Physics Section, Abdus Salam International Centre for Theoretical Physics, Strada Costiera, 11, Trieste 34151, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Farneti