Pacific Climate Variability : Insights from Coral Records, Earth System Models, and Novel Geochemical Tracers
出版項
2018
說明
1 online resource (211 pages)
文字
text
無媒介
computer
成冊
online resource
附註
Source: Dissertations Abstracts International, Volume: 80-01, Section: B
Publisher info.: Dissertation/Thesis
Advisor: Charles, Christopher D
Thesis (Ph.D.)--University of California, San Diego, 2018
Includes bibliographical references
This dissertation aims to understand the mechanisms and consequences of the low frequency “unforced” component of variability in the climate system using interannual and decadal variability as a platform to investigate phenomena thought to be sensitive to greenhouse gas emissions. To combat the lack of temporally extended instrumental observations, this dissertation relies on coral geochemistry and Earth System Models to identify the historical range of Pacific climate variability. Chapter 2 describes the analysis of a roughly 200 year-long coral record from Clarion Island, in the Revillagigedos Archipelago, Mexico. This record expresses substantial decadal variability in the oxygen isotopes, strongly coherent with other paleoproxies in the central equatorial Pacific and in Southern California, indicative of a coordinated system of ocean-atmospheric interaction. To best resolve the key processes involved, “forward models” are employed to interpret the decadal variability in the coral record. The third chapter complements the first by addressing a mechanism responsible for the modulation of decadal variability in the North Pacific; the Pacific Meridional Mode (PMM). The Community Earth System Model-Last Millennium Ensemble (CESM-LME) is used to estimate the historical range of PMM variability, highlighting the considerable power of natural variability within the system. I investigate the physical processes associated with adjustments in PMM variance, emphasizing that relatively small anomalies in the background state have a significant influence on PMM variability. Chapter 4 examines the roles of physical and biologically mediated processes on coral calcification from within an equatorial Pacific coral reef. Motivated by the biogeochemical implications of the previous sections, this work examines the manifestation of pH tracers in coral skeletal tissue across a network of diverse, monitored reef sites at Palmyra Atoll. Corals were analyzed for δ11B, trace metal, δ18 O, and δ13C composition. Despite a narrow range in the pH of seawater, high variance in δ11B were observed between sites, and within single sites, suggesting that individual coral colonies have differential capacities to regulate pH variability and other environmental stressors
Electronic reproduction. Ann Arbor, Mich. : ProQuest, 2019
