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| CORALS AND SCLEROSPONGES | ||||||||||
Ifaty Reef - Stable Isotope and Sr/Ca Data |
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Zinke, J., W.-C. Dullo, G.A. Heiss, and A. Eisenhauer. 2004. ENSO and Indian Ocean subtropical dipole variability is recorded in a coral record off southwest Madagascar for the period 1659 to 1995. Earth and Planetary Science Letters 228(1-2):177-194.
Start Year: 1659 AD End Year: 1995 AD Data: Please Cite Data Contributors! indian_ocean/ifaty2004.txt |
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Summary:The Ifaty coral record from off SW Madagascar provide a 336 years coral oxygen isotope record that is used to investigate the natural variability of the western Indian Ocean subtropical SST dipole and ENSO. The coral oxygen isotope record primarily reflects past sea-surface temperature (SST) variability on seasonal to multidecadal scales. To validate the SST reconstructions derived from oxygen isotopes, Sr/Ca ratios were obtained for selected time windows (1973 to 1995, 1863 to 1910, 1784 to 1809, 1688 to 1710). The period 1675-1760 was found to be the coolest period of the entire record with anomalies of 0.3-0.5ºC that includes the Late Maunder Minimum (1675-1710). The warmest periods, as indicated by our data, occur between 1880-1900 and the upper part of the Ifaty record (1973-1995). We generated a time series of coral d18O for different seasons of the year to investigate austral winter and summer SST variability that influences rainfall intensity over southern Africa. Winter coral d18O is coherent with winter SST on decadal and multidecadal time scales between 1854 to 1995. We suggest that the Ifaty winter time series provides a record of winter SST variability over the Mozambique Channel/Agulhas Current region over 336 years. Strong Indian Ocean subtropical dipole events, occurring during austral summer, are displayed in the Ifaty record. The austral summer coral d18O is coherent and in phase with ENSO indices on interannual time scales (2-4 years) between 1880-1920, 1930-40 and after 1970. Our data indicate that the impact of ENSO on SW Indian Ocean SST and atmospheric circulation was also strong between 1680-1720 and 1760-1790, in agreement with other studies. We show evidence that these variations are caused by changes in the regional hydrologic balance. The results demonstrate that the impact of ENSO cycles in the region of the SW Indian Ocean has changed significantly since 1970 and relate to a warming of southwestern Indian Ocean surface waters altering the spatial signature of ENSO.More Info on Corals and Sclerosponges |
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Parameters:del18O; SrCa; del13C |
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Complete XML Record:noaa-coral-1897 (Last Revised: 2007-09-05 ) |
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