A Fiji multi‐coral δ18O composite approach to obtaining a more accurate reconstruction of the last two‐centuries of the ocean‐climate variability in the South Pacific Convergence Zone region. (18th December 2014)

• Record Type: Journal Article
• Authors: Dassié, Emilie P.; Linsley, Braddock K.; Corrège, Thierry; Wu, Henry C.; Lemley, Gavin M.; Howe, Steve; Cabioch, Guy
• Is Part Of: Paleoceanography. Volume 29:Number 12(2014)
• Page Start: 1196
• Page End: 1213
• Publication Date: 2014-12-18
• Subjects: Paleoceanography -- Periodicals; 551.46
• DOI: 10.1002/2013PA002591
• Languages: English
• ISSNs: 0883-8305

Abstract

<abstract abstract-type="main"> <title>Abstract</title> <p>The limited availability of oceanographic data in the tropical Pacific Ocean prior to the satellite era makes coral‐based climate reconstructions a key tool for extending the instrumental record back in time, thereby providing a much needed test for climate models and projections. We have generated a unique regional network consisting of five <italic>Porites</italic> coral δ<sup>18</sup>O time series from different locations in the Fijian archipelago. Our results indicate that using a minimum of three <italic>Porites</italic> coral δ<sup>18</sup>O records from Fiji is statistically sufficient to obtain a reliable signal for climate reconstruction, and that application of an approach used in tree ring studies is a suitable tool to determine this number. The coral δ<sup>18</sup>O composite indicates that while sea surface temperature (SST) variability is the primary driver of seasonal δ<sup>18</sup>O variability in these Fiji corals, annual average coral δ<sup>18</sup>O is more closely correlated to sea surface salinity (SSS) as previously reported. Our results highlight the importance of water mass advection in controlling Fiji coral δ<sup>18</sup>O and salinity variability at interannual and decadal time scales despite being located in the heavy rainfall region of the South Pacific Convergence Zone (SPCZ). The Fiji δ<sup>18</sup>O composite presents a secular freshening and warming trend since the 1850s coupled with changes in both interannual (IA) and decadal/interdecadal (D/I) variance. The changes in IA and D/I variance suggest a re‐organization of climatic variability in the SPCZ region beginning in the late 1800s to period of a more dominant interannual variability, which could correspond to a southeast expansion of the SPCZ.</p> </abstract>