Records of baseline ocean-atmosphere variability provide critical context for understanding changes in mean climate state. However, ocean-atmosphere variability is not well understood during the time between the anomalous Medieval Warm Period/Little Ice Age and the present (the last ~500-800 years). This project-- a collaboration between Columbia University's Lamont Doherty Earth Observatory and Stanford University-- will develop a proxy record of variability in the western tropical Pacific over the past 500+ years. Coral cores collected from giant Porites colonies in Ta'u Island, American Samoa, will be analyzed for interannual- to centennial-scale variability in temperature and salinity (Sr/Ca and oxygen isotopes), indicating changes in the extent of the South Pacific Convergence Zone.
The researchers will partner with the National Park of American Samoa to construct an exhibit illustrating the use of long coral cores to study environmental change. This exhibit, displayed at the park's information center, will include Ta'u coral core material and data associated with this study. The project will support a post-doctoral researcher at Lamont and a graduate student at Stanford.
