Site survey and coring of potential IODP drill sites in the Western Pacific Warm Pool

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Intellectual Merit: The Indo-Pacific Warm Pool (IPWP) is the largest reservoir of warm surface water on earth, the major source of heat for the global atmosphere, and a location of deep atmospheric convection and heavy rainfall. Small variations in the sea surface temperature (SST) of the Western Pacific Warm Pool (WPWP), within the IPWP, influence the location and strength of convection in the rising limb of the Hadley and Walker circulations, perturbing planetary scale atmospheric circulation, atmospheric heating globally, and tropical hydrology. Until a decade ago, a high-resolution paleo-perspective on this critical area in paleoclimatic models was essentially non-existent due either to the lack of high-resolution records from the WPWP or because of the lack of records from key locations. The only available records came from low sedimentation rate sites that resolved glacial-interglacial (G-I) variability at best. However, recent work in the Indonesian Seaways and nearby seas has demonstrated the possibility of obtaining records from key locations in the WPWP, often with high resolution comparable to records from the high-latitude oceans. Here, the PIs propose to survey several sites that are potential candidates for obtaining long sediment records through the Integrated Ocean Drilling Program (IODP). These sites are strategically selected in order to resolve the effects of meridional (e.g., ITCZ displacement) vs. zonal (ENSO related) and vertical (thermocline depth) on the tropical climate at millennial, orbital and secular time scale. Broader Impacts: Reconstructions of equatorial climate have been among the highlights of paleoceanographic research of the last decade, by any measure. The records to be collected from this area have the potential to offer new insights into mechanisms of climate change and to help in testing climate models that are used for the IPCC predictions. Secondly, the project would enhance infrastructure for research by providing (to approved NSF data repositories immediately after the cruise) the seismic data necessary for IODP proposals that are based on collaborations among many proponents from different countries. Finally, through direct shipboard instruction and hands-on work, the cruise will provide training for the next generation of scientists in the intricacies of coring and multi-channel seismic data acquisition at sea, both of which are critical for furthering paleoceanographic research.