10² to 10³ year scale variability of the El Niño/Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD) in the eastern Indian Ocean over the last 30,000 years

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Recent studies agree that the Indonesian Archipelago plays a key role in present and past global climate. However, both proxy-based and modelling results differ when reconstructing the regional climate and its global implications, particularly on centennial to millennial timescales and during abrupt climate changes. These studies underline the need for hitherto missing high-resolution proxy evidence from the eastern Indian Ocean W and SW of the Indonesian Archipelago, a key region in tropical climate dynamics especially with regard to the Indian Ocean Dipole (IOD) and El Niño-Southern Oscillation (ENSO). Using planktonic foraminifera-based geochemical proxies in high-resolution sediment cores from off W- and SW-Indonesia, we aim to reconstruct past variations in the regional hydrography that is strongly affected by IOD/ENSO events. We will interpret these results in order to reconstruct past intensity of the IOD and its link to ENSO on the above mentioned time-scales. Despite recent progress in understanding the inter-annual aspects of ENSO and IOD, the basic characteristics of their long-term operation and their link to global climate are so far elusive. Our study will provide clues on the long-term behavior of these phenomena under different climate states and boundary conditions.