Tropical Atlantic Climate Variability and Ocean-Atmosphere Interactions

The tropical Atlantic exhibits complex climate variability driven by two-way interactions between the ocean and atmosphere. On interannual timescales, the Atlantic Niño—anomalous warming or cooling of the equatorial eastern Atlantic—modulates rainfall across West Africa, northeast Brazil and influences global teleconnections. Mechanisms such as the Bjerknes feedback amplify sea surface temperature (SST) anomalies through coupled changes in wind stress, upwelling and surface heat fluxes. At decadal to multidecadal scales, modes like the Atlantic Meridional Mode and fluctuations in the North Atlantic Oscillation shift the basin’s background state, altering the strength and pattern of atmospheric bridges that link the tropical Atlantic to the Pacific and Indian Oceans. These cross-basin pathways, realised via planetary-scale wave trains and oceanic currents, exert a profound influence on global climate patterns, seasonal predictability and extreme events. Recent advances in high-resolution coupled models, observational analyses and machine-learning tools are refining our understanding of causal relationships, improving forecasts from seasonal to decadal horizons, and informing adaptation strategies for vulnerable coastal regions.

Research from Nature Portfolio

Recent studies have shown that multidecadal variability in the North Atlantic Oscillation governs the strength of the North Tropical Atlantic’s influence on Pacific climate by modulating the persistence of SST anomalies and intensity of subtropical teleconnections, thereby explaining non-stationary links with El Niño–Southern Oscillation. In addition, unsupervised neural-network analyses have revealed a 50-year periodicity in SST anomalies across the tropical and South Atlantic, which underpins anti-correlated decadal rainfall patterns between northeast Brazil and western Africa. This low-frequency cycle emerges from evolving interactions among key Atlantic modes and offers a new framework for long-term precipitation forecasting in semi-arid coastlines.

Tropical Atlantic Climate Variability and Ocean-Atmosphere Interactions publication trend

The graph below shows the total number of articles in tropical atlantic climate variability and ocean-atmosphere interactions across all publications each year (not limited to Nature Index journals).

Technical terms

Atlantic Niño: Interannual warm or cold phase of SST anomalies in the equatorial eastern Atlantic, analogous to the Pacific El Niño/La Niña.

North Tropical Atlantic (NTA): Region between roughly 5° N and 20° N characterised by SST variability that influences remote climates.

Bjerknes feedback: Positive coupling between SST anomalies, wind stress and ocean upwelling that amplifies equatorial SST variations.

Ocean–atmosphere coupling: Two-way interactions between sea surface conditions and overlying atmospheric circulation.

Teleconnection: Climatic link between distant regions mediated by atmospheric wave trains or ocean currents.

Atlantic Meridional Mode (AMM): Variability pattern featuring a cross-equatorial SST gradient and associated wind anomalies, influencing interannual climate.

References

1. North Atlantic oscillation controls multidecadal changes in the North Tropical Atlantic−Pacific connection. Nature Communications (2023).
2. A 50-year cycle of sea surface temperature regulates decadal precipitation in the tropical and South Atlantic region. Communications Earth & Environment (2023).
3. Two regimes of inter-basin interactions between the Atlantic and Pacific Oceans on interannual timescales. npj Climate and Atmospheric Science (2023).
4. Impact of Indian Ocean Dipole on Atlantic Niño predictive skill. Environmental Research Letters (2023).
5. Assessing the tropical Atlantic biogeochemical processes in the Norwegian Earth System Model. Biogeosciences (2024).
6. The Bjerknes feedback in the tropical Atlantic in CMIP5 models. Climate Dynamics (2016).