P2C2: Tropical Response to Hemispheric Forcing--Testing Mechanisms Using Paleoclimate Data and Climate Models

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This project aims to identify and investigate the mechanisms linking the abrupt cooling events that occurred during the last glacial period over the North Atlantic (Heinrich events) and altered rainfall patterns throughout the global tropics. The research activities will address these questions by combining climate models and paleoclimate data. Specifically, existing proxy climate records will be used to produce new robust and unbiased syntheses of rainfall and sea-surface temperature changes during three different past intervals when the North Atlantic abruptly cooled and compare them against new and existing climate model simulations with the objective of testing the dominant mechanisms driving the tropical response to hemispheric forcing. These mechanisms will be contrasted with the responses to other hemispheric forcings, anthropogenic aerosols and volcanic eruptions, to assess their roles, and therefore improve the confidence of climate variability model predictions. The research has the potential to produce a complete theory of how the global tropics respond to North Atlantic cooling. This theory will provide a more complete understanding of the processes that give rise to inter-hemispheric asymmetries in tropical climate - one of the first order features of the Earth’s climate, as well as its response to climatic perturbations with inter-hemispheric asymmetries, such as anthropogenic aerosols, volcanic eruptions, or arctic sea ice loss. The potential Broader Impacts include advancing theoretical understanding of the mechanisms underlying climate perturbations transmitted through the tropics which has the potential to improve model predictions to a range of climate forcings, and more specifically, predictions of changes in tropical rainfall in heavily populated areas (the Americas, Africa, Asia). The data synthesis as well as model simulation will be made publicly available for the broad paleoclimate community as well as local students. Other Broader Impacts include training the next generation of climate researchers through the research framework developed in this project that will be incorporated in the researcher’s teaching activities. In addition, the researchers will be involved in outreach activities (Tournament of Science Olympiad) with the goal to advance climate system literacy in high school education.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.