Variability of the Indian Ocean Dipole during the last millennium
Abstract
The Indian Ocean Dipole (IOD) climate mode interacts with the El Niño-Southern Oscillation and Asian monsoon systems to drive climatic extremes around the Indian Ocean region. Coral reconstructions of the interannual variability of the IOD since the 1850s show an intensification in the frequency and strength of the positive phase of the IOD in recent decades, as well as strengthening of the interconnection between the IOD and Asian monsoon systems. Reconstructions of the mean climate state across the tropical Indian Ocean since the mid-Holocene also demonstrate the dynamic nature of the mean configuration of tropical Indian Ocean climate, suggesting that the IOD variability and interactions observed on interannual time scales may also persist over century to millennial scales. Here we present new oxygen isotope (δ18O) records from modern Porites corals collected on a transect along Java-Sumatra coasts. These corals, located within the IOD upwelling zone, are used to identify the location where optimum information about the occurrence and magnitude of positive IOD events can be gained from single corals. Precisely-dated fossil corals from this location of optimum IOD variability are then used to reconstruct highly resolved windows of IOD variability during the last millennium, including intervals corresponding to the northern hemisphere Little Ice Age and Medieval Warm Period.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFMPP51A1917A
- Keywords:
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- 4916 PALEOCEANOGRAPHY Corals;
- 1616 GLOBAL CHANGE Climate variability;
- 4870 OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL Stable isotopes;
- 4954 PALEOCEANOGRAPHY Sea surface temperature