Emily Elliott - US grants

A US-Japan Joint Seminar in hydrology will be held has to foster exchange of ideas, bridge gaps in research approaches, and to jointly develop prospective research directions. Historically, there has been limited interaction among scientists between the two countries because language, culture, and research foci separate these scientific communities. These differences highlight a potential for scientific discovery and are the reasons for this US-Japan Joint Seminar in hydrology. The purpose of this forthcoming seminar is to expand the theme of linking hydrology and biogeochemistry to consider effects of climatic and environmental change, as well as emerging measurement and analytical techniques used in catchment science research that allow fundamental scientific advancements. The meeting will host approximately 20 scientists from each country, including students and early career scientists, to present and discuss cutting-edge research in catchment sciences in an open forum to foster collaboration and exchange. The seminar will focus on the following aspects of hydrological and biogeochemical catchment sciences: (1) the role of hydrologic connectivity in regulating carbon and nitrogen cycling and export from catchments in the face of climatic and environmental change; (2) synthesis and cross-site comparison along climatic gradients to understand mechanisms of solute yields from catchments; (3) advances in techniques (trace gas fluxes, isotopic mass balances) for balancing nutrient budgets and better understanding processes (denitrification, transport, uptake, mineralization, etc.); and (4) integrating field observations with theory to inform better model predictions

The US-Japan Joint Seminar will 1) foster interaction and develop new collaborative research between US and Japanese catchment scientists, 2) stimulate and engage the next generation of scientists who will become leaders in research and support future interaction between the two countries, and 3) advance understanding of how catchments respond to climatic and environmental changes. Cross-continental synthesis is a challenge, yet a necessity for determining how catchments will respond to global environmental change. To meet that challenge, the proposed multi-perspective seminar in catchment hydrology and forest biogeochemistry will bring together established researchers and early career scientists, providing invaluable opportunities for synthesis in catchment sciences.

This project seeks to improve the paleoclimate record and the broader scientific understanding of past and future hydrologic variability in the South Atlantic Gulf Basin (AGB) and Southeastern (SE) United States by carrying out a three-year research program to investigate pre-instrumental streamflow and associated climate variability in this region.

The principle goals of the research program are to develop quantitative, multi-century, tree-ring reconstructions and to assess the risk of future streamflow in the SE and AGB. The specific aims of this project are to 1) develop streamflow reconstructions for eight major, coastal, interstate rivers; 2) conduct inter-basin comparisons to identify spatial and temporal patterns of common and disparate streamflow variability across the region; 3) provide novel insights on how the dynamical modes of climate variability (e.g., El Nino-Southern Oscillation, the North Atlantic Sub-tropical High, and Atlantic Multidecadal Oscillation) force regional expressions of climate change, hydrological variability, extreme drought and pluvial events, and potential regime shifts over the past 500-1,000 years and 4) characterize the risk of future streamflow and extreme events in these watersheds.

This research will provide insight into not only the long-term variability of streamflow, but will also shed light on the associated physical, social, economic and ecological impacts this variability has on coastal watersheds in the AGB and SE US. Improved understanding of streamflow variability will directly benefit the development of water policy in SE, by informing a variety of socially and economically relevant areas related to water withdrawals, streamflow forecasts, drought and flood mitigation.

Recent work on the Suwannee River (Florida) provides a successful example of how streamflow in the Southeast can be reconstructed over multiple centuries with high variance explained (R2=0.68) and robust validation statistics (RE, 0.71; CE, 0.81), in addition to providing novel insight into the controls of past hydroclimate to characterize and manage the risk of future streamflow in the AGB and SE.

The potential Broader Impacts include the potential for enhanced understanding of both the history of hydroclimate variability (especially extreme low flow events) and the role of regional and large-scale climate forcing mechanisms that drive streamflow variability. This project seeks to provide information useful for applied risk management around hydrologic extremes in the South Atlantic Gulf Basin (AGB) and Southeastern (SE) United States region. Understanding the timing and magnitude of past events and having accurate future forecasting is crucial for public and private stakeholders to prepare for the future and increase resiliency. In addition, by characterizing past, present and future streamflow and the risk of extreme events in the AGB and SE watersheds, this research will advance knowledge of how to protect and sustain riparian zones, coastal watersheds and surrounding lands now and into the future.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.