Journal of the Atmospheric Sciences · 1988 · 568 citations · 0 references
Natural SciencesEarth SciencesMeteorologyAtmospheric ScienceClimate ScienceOcean WavesAtmosphere-ocean InteractionsEl Niño-southern OscillationOcean-atmosphere CouplingOcean-atmosphere InteractionSea Surface TemperatureSea Surface Temperature VariabilityAir - Sea Heat FluxesAtmosphere-ocean CouplingCoupled Atmosphere-ocean ModelingCoupled Ocean-atmosphere InteractionCoupled Ocean-atmosphere ModelingEnso Decadal VariabilityOcean-atmosphere VariabilityTropical Ocean-atmosphere Coupling
The study uses two‑level nonlinear primitive equation models for the ocean and atmosphere, with the atmosphere forced by steady zonally symmetric Newtonian heating, the ocean confined to a rectangular tropical basin, and linear air–sea heat fluxes and wind‑dependent interfacial stress coupling the two. The 35‑year integration shows self‑sustained ENSO‑like oscillations on 3–5‑year timescales, driven by unstable coupled modes whose period depends on ocean wave propagation in the closed basin.
Results are presented from a 35-year integration of a coupled ocean-atmosphere model. Both ocean and atmosphere are two-level, nonlinear primitive equations models. The global atmospheric model is forced by a steady, zonally symmetric Newtonian heating. The ocean model is solved in a rectangular tropical basin. Heat fluxes between ocean and atmosphere are linear in air-sea temperature differences, and the interfacial stress is proportional to lower-level atmospheric winds. The coupled models produce ENSO-like variability on time scales of 3 to 5 years. Since there is no external time-dependent forcing, these are self-sustained vacillations of the nonlinear system. It is argued that the energetics of the vacillations is that of unstable coupled modes and that the time scale is crucially dependent on the effects of ocean waves propagating in a closed basin.