annual cycles of d18O, verified using annual growth bands

IOD  upwelling  cools  the ambient  SST  and  decreases  rainfall,  both  of  which  increase coral d18O.

Mentawai Islands coral isotope record, 1958-1997

d18O (Ocean2kHR_010): interpretation4_scope: '' has been replaced by 'isotope'

Column 'addRnUTq7GObLYuHDpun', with variable name 'yearEnsemble', was added to the dataset
Column 'addRRaOWZMiPwitaUmrv', with variable name 'yearEnsemble', was added to the dataset

Abram, N.J., M.K. Gagan, J.E. Cole, W.S. Hantoro, and M. Mudelsee

Abram, N. J., Gagan, M. K., Cole, J. E., Hantoro, W. S. and Mudelsee, M.: Recent intensification of tropical climate variability in the Indian Ocean, Nature Geoscience, 1(12), 849–853, doi:10.1038/ngeo357, 2008.

Recent intensification of tropical climate variability in the Indian Ocean

Mantawai Islands, West Sumatra, Indonesia

Finnigan MAT 253 isotope ratio mass spectrometer coupled to a Kiel III carbonate device at WHOI

Age models were developed using density banding visible in the X radiographs to identify the calendar year. X radiographs for these corals have been previously published [Goodkin, 2007; Goodkin et al., 2007, 2005]. Some error is expected within this age model because of years of very little or no growth, not visible on the X ray and also not clearly discernible in the seasonal cycles of Sr/Ca. While there is the potential for error generated by noise in the Sr/Ca or the annual band counting to result in the inappropriate addition of a year, the majority of age model error will arise because of missing years, generating a bias in which coral bands are assigned to artificially recent (younger) dates. For example, if the coral did not grow in 1950, 1949 would be inappropriately assigned the date 1950, and similarly for all coral years prior to 1950 (1781?1949). Such age model bias is suspected during the early to mid-1800s when growth rates were extremely slow for an extended period of time and hiatuses in growth may have occurred [Goodkin et al., 2005].