Possible shift in controls of the tropical Pacific surface warming pattern

Area of Science:

• Climate Science
• Oceanography
• Atmospheric Science

Background:

• Sea surface temperature (SST) patterns in the tropical Pacific significantly influence global warming and regional climate.
• Observed recent decades' changes, including enhanced zonal SST contrast and strengthened Walker circulation, remain a subject of scientific debate.
• Accurate projections of future climate depend on understanding the drivers of these SST pattern changes.

Purpose of the Study:

• To investigate the drivers of tropical Pacific sea surface temperature pattern changes.
• To review and reconcile energy and dynamical perspectives on external forcing's role.
• To project future shifts in the mechanisms governing SST pattern evolution.

Main Methods:

• Review of existing mechanisms for forced response, categorized by energy and dynamical perspectives.
• Analysis of collective and relative contributions of these perspectives to past and future SST changes.
• Synthesis of findings to propose a narrative reconciling different viewpoints.

Main Results:

• The study suggests that strengthening mechanisms have historically dominated tropical Pacific SST pattern changes.
• Future projections indicate a shift, with weakening mechanisms expected to dominate.
• A reconciliation of energy and dynamical perspectives on external forcing is proposed.

Conclusions:

• External forcing plays a critical role in modulating tropical Pacific SST patterns.
• The balance of strengthening versus weakening mechanisms is projected to shift in the future.
• Resolving model-observation discrepancies is key to improving climate projections.