Precipitation changes in the western tropical Pacific over the past millennium

Julie N. Richey; Julian P. Sachs

doi:10.1130/g37822.1

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Precipitation changes in the western tropical Pacific over the past millennium

Julie N. Richey·Julian P. Sachs

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Abstract

Modern seasonal and inter-annual precipitation variability in Palau is linked to both meridional movement of the Intertropical Convergence Zone (ITCZ) and changes in the Pacific Walker Circula- tion (PWC) associated with the El Niño–Southern Oscillation. Thus, Palau’s hydroclimate should be sensitive to mean shifts in the ITCZ and PWC on decadal to centennial time scales. Using compound- specific hydrogen isotope ratios (δ2H) of dinosterol in lake sediments, we generated a decadal-resolution proxy record of hydroclimatic variability in Palau spanning the past 800 yr. Results indicate a dry- ing trend during the Little Ice Age in Palau, consistent with a south- ward displacement of the ITCZ. In addition to the secular drying trend, there are persistent large (~20‰) multi-decadal to centennial oscillations in the δ2H record, the most recent of which indicates an abrupt shift to drier conditions in the mid-1970s that coincides with a decadal-scale negative shift in the Southern Oscillation Index.

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Geology Article

Source-reported bounding extent: 6.820079977465815° to 8.18430516386163° latitude; 134.033203125° to 134.79400634765625° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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BibTeX RIS

Julie N. Richey, Julian P. Sachs. 2016-08-01. Precipitation changes in the western tropical Pacific over the past millennium. https://doi.org/10.1130/g37822.1

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