Collaborative Research: P2C2--Reconstructing Deglacial and Holocene Climate Variability in Southeast Asia Using Speleothems and Isotope-Enabled Model Simulations

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The Asian Monsoon system is an important component of the global climate system that plays a major role in the transport of heat and moisture from the tropics to higher latitudes. Even small variations in the strength and/or timing of seasonal rainfall can have significant impacts on the billions of people living within the Asian monsoon domain, yet climate model projections of future monsoon changes still remain uncertain. While paleoclimate records have significantly advanced our understanding of summer monsoon variability in some regions, we still know very little about the range and mechanisms of monsoon variability in Southeast Asia. This research, a collaborative effort between scientists from the University of California, Irvine and William Patterson College of New Jersey, will generate high-resolution speleothem (cave calcite deposit) records of past hydroclimate variability over the last 20,000 years from Laos, a key site at the interface between the Indian and East Asian monsoon systems. The new oxygen isotope records will document changes in Southeast Asian monsoon strength on sub-decadal to orbital timescales, filling in a key spatial and temporal gap in the paleoclimate record of the tropics. Through integrating paleoclimate proxy data, instrumental climate data, and climate model analyses, the project will address three main questions: (1) How has Southeast Asian monsoon intensity varied over the past 20,000 years in response to orbital forcing, millennial-scale abrupt climate events, and interannual to multi-decadal climate modes?; (2) What are the mechanisms that control precipitation and speleothem oxygen isotopes on interannual to orbital timescales in Laos?; and (3) How do the Laos speleothem records relate to broader spatial and temporal patterns of past climate variability in the tropical Indo-Pacific, the Asian monsoon region, and high latitudes? In addition to the scientific outcomes, this project will provide research opportunities for graduate and undergraduate students and will be incorporated in outreach efforts aimed at improving the participation of underrepresented groups in the geosciences. For instance, a hands-on field and laboratory exercise on paleoclimate, climate change, and native culture will be developed for the NSF funded American Indian Summer Institute in Earth System Science held at the University of California, Irvine each summer.