Nurhati, Intan S. , Cobb, Kim M. , Di Lorenzo, Emanuele

Nurhati, I. S., Cobb, K. M. and Di Lorenzo, E.: Decadal-Scale SST and Salinity Variations in the Central Tropical Pacific: Signatures of Natural and Anthropogenic Climate Change, Journal of Climate, 24(13), 3294–3308, doi:10.1175/2011jcli3852.1, 2011.

DecadalScale SST and Salinity Variations in the Central Tropical Pacific: Signatures of Natural and Anthropogenic Climate Change

Thermo-Finnigan MAT253 Isotope Ratio Mass Spectrometer (IRMS), with a Kiel IV Carbonate Device, and on a Thermo-Finnigan Delta V Plus IRMS with Gasbench II (GB II) connected to a Conflo IV, both at the Analytical Laboratory for Paleoclimate Studies (ALPS) at the Jackson School of Geosciences, University of Texas at Austin. The precision of the Kiel IV/MAT253 IRMS for samples in this study is 0.05? for d18O and 0.03? for d13C (1s), as estimated via multiple analyses of a carbonate standard (n = 224), which is consistent with longterm precision for this instrument of 0.06? for d18O and 0.03? for d13C. The precision of the GB II/Delta V Plus IRMS is 0.07? for d18O and 0.03? for d13C (1s), as estimated via multiple analyses of the same carbonate standard (n = 25), which is consistent with long-term precision for this instrument of 0.07? for d18O and 0.03? for d13C. Replicate coral samples analyzed on both mass spectrometers yield similar results (mean difference = 0.03? for d18O and 0.12? for d13C; n = 35).

Yes, results are only reported to a depth of 200 cm as a result of diagenetic alteration at the bottom of the core, which is visible as dark patches in the Xradiographs and large excursions, as well as the lack of an annual cycle in the geochemical time series.

Geochemical variations versus depth were converted to variations versus time using AnalySeries software [Paillard et al., 1996]. Geochemical variations in d18O were used to determine a first-order age model, with the maximum intra-annual peaks in d18O being assigned as the coldest month of the year (August), beginning with the year 2007, when the living coral was cored. This first-order age model places d18O variations in the time domain, with uneven time increments (Dt). A second-order age model, with a monthly Dt, was created using the AnalySeries software program, which was verified by comparing years with anomalous d18O values to known ENSO events where possible. This second-order age model is the final age model used in all plots and data analysis.