Interannual atmospheric variability forced by the deep equatorial Atlantic Ocean.

Area of Science:

• Oceanography
• Atmospheric Science
• Climate Dynamics

Background:

• Tropical Atlantic climate variability is influenced by ocean-atmosphere interactions, El Niño/Southern Oscillation, and North Atlantic Oscillation.
• Existing models suggest decadal and interannual variability are dominated by two coupled ocean-atmosphere modes.
• The role of intrinsic deep ocean dynamics in tropical Atlantic climate has been less understood.

Purpose of the Study:

• To investigate the impact of deep equatorial Atlantic ocean dynamics on regional climate patterns.
• To identify and characterize novel climate cycles within the tropical Atlantic.
• To assess the potential for improving climate predictions using these findings.

Main Methods:

• Analysis of deep oceanographic data to identify deep zonal jets.
• Tracking energy propagation from deep ocean to the surface.
• Correlating deep jet activity with sea surface temperature, wind, and rainfall anomalies.

Main Results:

• Discovery of vertically alternating deep zonal jets with a 4.5-year period in the deep Atlantic.
• Observed upward energy propagation of these jets to the sea surface.
• Linked surface anomalies to equatorial currents, eastern Atlantic temperatures, and distinct weather patterns.

Conclusions:

• Deep ocean dynamics in the equatorial Atlantic drive a significant 4.5-year climate cycle.
• This cycle influences sea surface temperature, wind, and rainfall, impacting regional climate.
• The identified oscillatory behavior offers potential for enhanced tropical Atlantic climate predictions.