Collaborative Research: Reconstructing Interactions Between the East Asian Monsoon and Westerly Jet at Multiple Timescales via the Flux and Provenance of Eolian and Fluvial Supply

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Original TitleCollaborative Research: Reconstructing Interactions Between the East Asian Monsoon and Westerly Jet at Multiple Timescales via the Flux and Provenance of Eolian and Fluvial SupplyRevised TitleReconstructing interactions between the East Asian Monsoon and Westerly Jet at multiple timescales based on wind-supplied dust and fluvial inputs to continental margin sedimentsNon-Technical AbstractThis research will build robust new records of East Asian climate variability, which determines precipitation seasonality and intensity for over 20% of the world's population. The proposal seeks to determine the average state and variability of the Westerly Jet and its relationship to the East Asian Monsoon during key intervals of the last 3 million years spanning a wide range of background climates. This will yield a heretofore unrealized understanding of climatic sensitivity and behavior in this globally critical region. The researchers will examine the input of wind-blown dust and riverine material by studying their chemical and isotopic composition at several key marine locations in the Japan Sea/East Sea and East China Sea. Land-derived material is primarily delivered to the Japan Sea/East Sea by wind, reflecting Westerly Jet behavior, and to the East China Sea by the Yangtze River, reflecting precipitation intensity and distribution in interior China. Tracing changes in these inputs can be used to make inferences about the atmospheric and precipitation regimes of Asia. This project addresses the climate sensitivity and behavior of a critical part of the climate system that is of high relevance to society. In addition to integrating efforts at three participating institutions, this proposal builds on collaborations with other scientists developing complementary records of regional climate, including multiple studies reflecting East Asian summer monsoon strength. The proposed research involves 40% of the expedition's US scientific party, brings together a high number of national and international collaborators, leverages off of other funding resources (US and internationally), and directly contributes to undergraduate and graduate education at all three institutions and beyond.Technical AbstractThis proposal seeks to build robust new records of East Asian climate variability on millennial to million-year timescales through examination of chemical and isotopic tracers of terrigenous provenance and flux in the Japan Sea/East Sea and East China Sea. Terrigenous material is primarily delivered to the Japan Sea/East Sea by wind, reflecting Westerly Jet behavior, and to the East China Sea by the Yangtze River, reflecting precipitation intensity and distribution in interior China. The proposal aims to determine the mean state and variability of the Westerly Jet and its coupling with the East Asian Monsoon, with a particular focus on the Plio-Pleistocene boundary, the Mid-Pleistocene Transition, and the last ~450 ka, and will yield a heretofore unrealized understanding of climatic sensitivity and behavior in this globally critical region. Newly collected sediment cores from IODP Expedition 346 (Asian Monsoon) offer a unique opportunity to produce continuous records with millennial-scale resolution spanning millions of years. The researchers will use XRF core scanning to provide high-resolution, continuous records, and perform elemental and isotopic analyses in specific time intervals to provide detailed insights into changes in eolian and fluvial sediment sources. Integrating XRF scanning records with quantitative chemical and isotopic tracers is surprisingly uncommon. The proposed research incorporates newly developed analytical and statistical methods for identifying dispersed volcanic ash in the sediment, which will ensure that the terrigenous (erosional) signal is not combined with a volcanic signal. This project addresses climate sensitivity and behavior in key time intervals of high relevance to understanding global climate systematics. The East Asian Monsoon determines precipitation seasonality and intensity for over 20% of the world's population. The research directly addresses objectives of IODP Expedition 346, involves 40% of the expedition's US scientific party, involves a high number of national and international collaborators, leverages off of other funding resources (US and internationally), and directly contributes to undergraduate and graduate education at all three institutions and beyond.