Patterns of Pacific decadal variability recorded by Indian Ocean corals |
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| Authors: | Traute Crueger Jens Zinke Miriam Pfeiffer |
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| Institution: | (1) Max Planck Institute for Meteorology, Hamburg, Bundesstrasse 53, 20146 Hamburg, Germany;(2) Vrije Universiteit Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands;(3) Leibniz Institut für Meereswissenschaften, IFM-GEOMAR Kiel, Wischhofstrasse 1-3, 24148 Kiel, Germany |
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| Abstract: | We investigate Pacific Decadal Oscillation (PDO) signals recorded by two bimonthly resolved coral δ18O series from La Réunion and Ifaty (West Madagascar), Indian Ocean from 1882 to 1993. To isolate the main PDO frequencies,
we apply a band pass filter to the time series passing only periodicities from 16 to 28 years. We investigate the covariance
patterns of the coral time series with sea surface temperature (SST) and sea level pressure (SLP) of the Indian and Pacific
Oceans. In addition, the empirical orthogonal functions of the filtered SST and SLP fields (single and coupled) are related
to the filtered coral times series. The covariance maps show the typical PDO pattern for SST and SLP, confirming the coupling
between the Indian and Pacific Oceans. Both corals show the strongest signal in boreal summer. The La Réunion (Ifaty) coral
better records SST (SLP) than SLP (SST) pattern variability. We suggest that the filtered La Réunion coral δ18O represents δ18O of seawater that varies with the South Equatorial Current, which, in turn, is linked with the SST PDO. The filtered Ifaty
coral δ18O represents SST and is remotely linked with the SLP PDO variability. A combined coral record of the Ifaty and La Réunion
boreal summer δ18O series explains about 64% of the variance of the coupled SST/SLP PDO time series.
AGU OS06 special issue “Ocean’s role in climate change—a paleo perspective”. |
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| Keywords: | Corals δ 18O Pacific Decadal Oscillation (PDO) Indian Ocean South Equatorial Current (SEC) Mozambique Channel Eddies (MCE) Climate reconstruction |
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