Coral [delta] 18 O records from Palau and Eastern Island : contributions to the network of Pan-Pacific high-resolution paleoclimate records
Abstract/Contents
- Abstract
- Coral-based proxy records are one of the most powerful tools for extending our understanding of interannual to centennial modes associated with El Niño-Southern Oscillation (ENSO) variability. Such records are also crucial for constraining forecasts under various greenhouse gas emission scenarios. In this dissertation I present an examination of records obtained from two study sites: The Republic of Palau (7.5°N 134.5°E) and Easter Island (27°S 109°W). This dissertation is organized into five chapters and an appendix. Chapter 1 is an introduction to paleoclimate, ENSO, and coral-based proxy records. In Chapter 2, I present the analysis of four records from Palau that were sampled from diverse localities within this study region. We take advantage of the multiple instrumental products and previously published results in our evaluation of the Palau coral [delta] 18O ([delta] 18OCRL) signal. Our primary conclusion in Chapter 2 is that Palau [delta] 18OCRL is well suited to capture ENSO, regardless of the coral environmental setting. We also show that Palau [delta] 18OCRL is primarily related to salinity, with temperature exerting a secondary influence. In Chapter 3 we apply our [delta] 18OCRL calibration results from Palau to the pre-instrumental period. Our records exhibit excellent reproducibility over the 20th century, and show strong coherence with other tropical Pacific [delta] 18OCRL records. We identify a 23/24 year cycle which is robust throughout the West Pacific Warm Pool (WPWP) following the end of the Little Ice Age (LIA). The Palau records show a long-term trend indicative of warming and/or freshening. Chapter 4 presents the results of three previously unpublished [delta] 18OCRL records from Easter Island, which resides in a region that is particularly devoid of high-resolution paleoclimate observations. All of the Easter Island corals display complex growth morphology. As a result, we deploy a range of techniques to develop age models. Our chief conclusion is that the Easter Island [delta] 18OCRL records closely follow hemispheric and global scale temperature trends over the 20th century. We also observe unique seasonal trends, which are likely attributable biases in seasonal carbonate precipitation and our age model schemes. Our analyses of the Easter Island [delta] 18OCRL records support the assertion that decadal variability across the Pacific basin originates in the tropics. All of the [delta] 18OCRL records presented in this dissertation represent significant contributions our understanding of Pan-Pacific climate variability over the past two centuries.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2014 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Osborne, Michael Cleveland |
|---|---|
| Associated with | Stanford University, Department of Environmental Earth System Science. |
| Primary advisor | Dunbar, Robert |
| Thesis advisor | Dunbar, Robert |
| Thesis advisor | Arrigo, Kevin R |
| Thesis advisor | Chamberlain, C. Page |
| Thesis advisor | Maher, Katharine |
| Advisor | Arrigo, Kevin R |
| Advisor | Chamberlain, C. Page |
| Advisor | Maher, Katharine |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Michael C. Osborne. |
|---|---|
| Note | Submitted to the Department of Environmental Earth System Science. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2014. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2014 by Michael Cleveland Osborne
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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