Examining Late Twentieth Century Trends in the Central Tropical Pacific

Abstract

Examining Late Twentieth Century Trends in the Central Tropical Pacific. Ted Conroy, May 2015. University of Hawaii at Manoa. Coral Proxy records are key to understanding the El Niño Southern Oscillation (ENSO) prior to the observational era. This study investigates how coral proxy records have captured changes over the late twentieth century, the most observational rich time period in history. An isotope enabled regional ocean modeling system (isoROMS) was used for this study, and allows for oxygen isotopic ratios (δ18O) to be calculated and directly compared to corals. Results show that Sr/Ca ratios record sea surface temperature trends well; however, a nonlinear relationship between sea surface salinity and seawater δ18O complicates paleo-salinity measurements. Also, late twentieth century warming and freshening trends in the central tropical Pacific appear to be strongly influenced by decadal changes that must be identified to understand long term anthropogenic effects.