Collaborative Research: Reconstructing millennial-scale trends and variability in western Pacific convection and hydrology from large lakes on Sulawesi, central Indonesia

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This grant supports research on late Pleistocene and Holocene convective and hydrologic variability in Indonesia through the recovery and analysis of new sediment cores from two large lakes on the island of Sulawesi. This research builds upon seismic reflection surveys of these lakes that document thick piles of sediment accumulating at rates ideal for paleoclimate studies, and upon geochemical and isotopic analyses of existing short cores that indicate substantial changes in regional convection and hydrology during the past ca. 400 years. This group will recover new sediment cores from these lakes, and conduct multiproxy analyses to reconstruct convective and hydrologic variability during the late Pleistocene and Holocene. This work will provide fundamentally important new insights into the history of Indonesian convection and hydrology, changes in the ITCZ, and long-term changes in tropical Pacific zonal gradients in during the late Pleistocene and Holocene.Intellectual Merits: The research is in two key areas: 1) The regional responses of coupled climate systems such as the ITCZ and ENSO during past climate changes, and 2) The regional impact of past abrupt changes in climate. Interannual variability in Indonesian rainfall and hydrology are linked to variations in ENSO. Understanding the role of long-term changes in natural modes of variability such as ENSO in abrupt climate change is a critical question, yet existing records disagree substantially on the response of western Pacific hydrology to abrupt climate changes. Records of climate from these lakes will provide fundamentally important data to evaluate centennial- to millennial-scale trends and variability in tropical western Pacific convection and hydrology, and interactions between the mean state of the tropical Pacific, the regional monsoons, and the strength and position of the ITCZ during past climate changes.Broader Impacts: The proposed research activities will provide a new record of climate variability from a densely inhabited, rapidly developing region where food production has been quantitatively linked to ENSO-driven rainfall variability. Lakes Matano and Towuti have been proposed as important sites for continental drilling to obtain long paleoenvironmental records from the tropical Pacific, and our fieldwork will provide new sediment cores and seismic reflection data to the scientific community from these scientifically valuable but understudied great lakes. The proposed research will promote interdisciplinary training and learning through involvement of undergraduate and graduate students in an effort to expand our fundamental knowledge of climate variability in an important region. The project will also enhance infrastructure for research and education by strengthening intellectual and research collaborations between the PIs, Indonesian, Canadian scientists and institutions, and industry, and through support of infrastructure at Brown University and the University of Minnesota.