Thermodynamic controls of the Atlantic Nio. Academic Article uri icon

abstract

  • Prevailing theories on the equatorial Atlantic Nio 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 Nio s.d. of 0.280.07K, explaining 6823% of the observed interannual variability. Thus, in state-of-the-art coupled models, Atlantic Nio variability strongly depends on the thermodynamic component (R(2)=0.92). Coupled dynamics acts to improve the characteristic Nio-like spatial structure but not necessarily the variance. Perturbations of the equatorial Atlantic trade winds (1.53ms(-1)) can drive changes in surface latent heat flux (14.35Wm(-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.

published proceedings

  • Nat Commun

altmetric score

  • 40.75

author list (cited authors)

  • Nnamchi, H. C., Li, J., Kucharski, F., Kang, I., Keenlyside, N. S., Chang, P., & Farneti, R.

citation count

  • 60

complete list of authors

  • Nnamchi, Hyacinth C||Li, Jianping||Kucharski, Fred||Kang, In-Sik||Keenlyside, Noel S||Chang, Ping||Farneti, Riccardo

publication date

  • November 2015