This project involves a cross-calibration of speleothems and tree rings at two locations in northern and southern Lao PDR at locations uniquely situated to address fundamental questions in tropical paleoclimatology. Such fundamental questions include: What are the relative roles of, and inter-relationships between, the El Nino-Southern Oscillation (ENSO) and the Intertropical Convergence Zone (ITCZ) in influencing Southeast Asian climate variability? Currently, there is no coherent understanding of how the archives from these phenomena reflect climate, specifically how the physical or eco-physiological controls of each influence the stable isotope records extracted from them.
The research team aims to better understand the processes that control the transfer of atmospheric and land surface climate signals to climate proxies by addressing the following questions: 1) How are temperature, precipitation, and stable isotopic variations recorded in the physical, chemical, and biologic signatures of each archive? 2) Are local and regional climate signals synchronous between speleothems and tree rings? and 3) Do the inherent climate signals exhibit inter-proxy variability with seasonal bias or low vs. high frequency variability, and if so, why?
The specific objectives of the research include: i) exploring the dominant controls on and interrelationships between tropical speleothems and tree-rings through a paired cave and tree modern calibration study at two sites in Laos; ii) examining the dominant controls on speleothem and tree-ring stable isotope records for the instrumental period through proxy system modeling and comparison of new and existing records with instrumental climate data and modeled precipitation delta 18 Oxygen; and iii) extending the paleoclimate record back through the last millennium utilizing new and previously collected speleothems and tree cores from North and South Laos.
The potential broader impacts cover three specific areas: research, mentorship, outreach.
On the research side, the project aims to tackle aspects of evolving areas of controversy integrating climate proxies across climate archives and climatic events.
In terms of mentoring, the project supports graduate students during the academic year and undergraduate students in summer research in the Manhattan Center for Science and Mathematics. Students will assist with fieldwork, data processing and analysis, co-authorship of papers, and presentations of results. One of the collaborative institutions, William Patterson University, a Hispanic Serving Institution, is largely a teaching university with a diverse student body that includes many underrepresented minorities that are first generation to college.
Outreach is conducted by all the Collaborators. One of the Principal Investigators is a female Native American scientist and organizes the American Indian Summer Institute in Earth System Science, a two-week residential program for high school students. Another Principal Investigator organizes an annual international Ecological Field School in Vietnam.
