Mechanisms and Effects of Tropical Indian Ocean Variability

University Of California-San Diego Scripps Inst Of Oceanography, La Jolla CA

Investigators

Abstract

A new concept of the tropical Indian Ocean (TIO) capacitor effect is emerging for interactions between the Indian and Pacific basins: El Nino teleconnection causes the TIO to warm, and the TIO warming persists and like a discharging capacitor, exerts climatic influences after El Nino decays. Studies of the capacitor effect so far tend to be diagnostic, and targeted model experiments are necessary to make further progress. This project will study ocean-atmospheric processes and mechanisms for the TIO response to El Nino/the Southern Oscillation (ENSO), especially the long persistence and climatic effects of this response during and after the decay of an ENSO event; and to explore interdecadal changes in TIO mean state and variability and determine their cause. A state-of-the-art coupled general circulation model will be used to conduct experiments and test hypotheses regarding the role of ocean Rossby waves in sustaining the TIO warming and moist teleconnection from the TIO to the Northwest Pacific via atmospheric Kelvin wave. Among teleconnective effects of the TIO warming are reduced precipitation over the subtropical Northwest Pacific (including the U.S. affiliated Northern Mariana Islands and Guam), and an anomalously active Meiyu-Baiu rainy season from eastern China to Japan. The proposed research represents a systematic investigation into the TIO's role in climate and will yield new insights into the mechanisms for TIO variability and changes. The successful completion of this project has the potential in improving understanding and prediction of climate variability and change, which benefits countries/communities within and rimming the TIO and Northwest Pacific. Graduate students and postdoctoral will be trained and supported.