Collaborative Research: A 650,000 year record of hydroclimate in the Western Pacific Warm Pool: Scientific Drilling at Lake Towuti, Indonesia

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NON-TECHNICAL ABSTRACTThis research will reconstruct the past climatic and environmental change in central Indonesia over the last 650,000 years. To accomplish this goal, project scientists will drill long sediment cores from the bottom of Lake Towuti, a large lake on the island of Sulawesi, Indonesia, which contains the longest known record of terrestrial climate from anywhere in southeast Asia. These cores will be analyzed for their physical, chemical, and biological properties to deduce past variations in rainfall in the heart of the tropical Pacific region. These data will be used to assess the response of regional rainfall to changes in orbital cycles, greenhouse-gas variations, and global glacial-interglacial cycles.The tropical western Pacific is an extremely important part of the global climate system, yet its response to global climate forcings and change remains poorly understood. This work will provide the longest continuous record of climate available to investigate the fundamental processes that control Indonesian climate variations. The research team will collaborate with scientists from Indonesia, Germany, Switzerland, Canada, and Australia on this project, stimulating interdisciplinary and international research training opportunities for students and teachers. The project will contribute to developing new museum displays and will engage the public via live web outreach activities.TECHNICAL ABSTRACTLake Towuti is the largest tectonic lake in Southeast Asia and is a high priority paleoclimate target within the International Continental Scientific Drilling Program (ICDP). Seismic reflection and shallow sediment cores indicate that Lake Towuti contains a 100-200 m thick section of stratified lacustrine sediment that continuously spans the last ~650,000 years BP, the longest known terrestrial section in Southeast Asia. This research--a collaboration between scientists from Brown University, the University of Rhode Island, and the University of Minnesota--will investigate the response of tropical western Pacific climate to changes in orbital forcing and global climate boundary conditions through the late Pleistocene. The research is part of a multinational drilling program on Lake Towuti. This award provides funding to drill, to develop age models for the cores, and generate climate proxy reconstructions of the past ~650,000 years based upon a suite sedimentological, geochemical, and organic geochemical measurements.Intellectual Merit: Changes in tropical western Pacific hydrology exert enormous influence on global atmospheric circulation and on the concentration of atmospheric water vapor, the most abundant greenhouse gas. Despite its importance, the response of western Pacific hydrology to global climate remains highly uncertain. The team will collect and develop the longest continuous record of climate available from this region and compare this record with reconstructions from low and high-latitude marine and terrestrial sites to understand the response of tropical Pacific hydroclimate to changes in orbital forcing and global climate boundary conditions during the last 650,000 years.Broader Impacts: This work will provide important insight into the mechanisms governing long-term change in tropical hydrology and will provide a benchmark test-bed for paleoclimate models to simulate climate under different boundary conditions than the present. This project will provide interdisciplinary, international research training and learning opportunities to US and Indonesian students and scientists. This work will contribute to the development of new museum displays, and will engage the public with scientists in the field via interactions through web outreach activities. The research to date generated considerable publicity and local educational opportunities within Indonesia, including documentary programs on national television. The team will continue these activities throughout this project.