Climate-Informed Estimation of Hydrologic Extremes for Robust Adaptation to Non-Stationary Climate
Dr. Casey Brown | University of Massachusetts
The objective of this project is to develop and evaluate methods to produce the next generation of intensity-duration-frequency (IDF) curves relevant for engineering design at Department of Defense (DoD) installations. The research will demonstrate the utility of the methods that link non-stationary statistical analyses of observed hydrometeorological extremes to climate information produced through Earth system modeling. An assessment of climate modeling methods will be made in terms of their ability to inform the key climate information needs that emerge from an analysis of historical non-stationarity already realized in the observed record. The project will evaluate the relative advantage of various climate information tailoring methods, including different dynamical downscaling techniques, in terms of their ability to provide credible climate information relevant to hydrologic extremes. Through this research, a robust method will be developed for estimating future changes in hydrologic extremes based on merged historical observations and credible climate projections and implications highlighted for engineering practice by providing infrastructure design guidance that addresses the revealed range of uncertainty. The results will improve the design of hydrologic infrastructure on DoD installations by incorporating methods for recognizing and managing future climate trends.
The technical approach includes four tasks. The analysis begins with an assessment of historical non-stationarity in hydrometeorological extremes across a geographic region containing several DoD installations. The analysis will focus on identifying the large-scale physical hydroclimatic mechanisms driving non-stationarity in regional hydrometeorological records. Initial focus on tropical moisture exports and snowpack-related hydrologic extremes will be expanded, if appropriate, based on the results of the analysis. Through a process-based analysis of historical extremes, the climate information needed to understand future shifts in extreme event distributions will be identified and will serve as the basis for the assessment of climate simulation products. The second task is an assessment of climate simulations and downscaling approaches in terms of their relative ability to provide credible projections of the climate information directly related to extreme event genesis. Based on the results of this assessment, in the third task, the project team will couple credible climate projections with trends in historical observations to produce a synthesized statistical model of non-stationary hydrologic extremes. Finally, in the fourth task the statistical models will be piloted for two engineering decision processes related to extreme events.
This project will produce a statistical framework for the credible projection of future extremes that provides guidance on the use of historical and projection-based climate information to inform engineering design and management processes. An assessment of dynamical downscaling and bias correction methodologies evaluated in terms of their ability to produce needed climate information for DoD engineering practice will be produced and priority climate research needs relevant to hydrologic extremes identified. The analysis also will produce guidance that describes novel approaches for using the developed statistical information for engineering design that is robust to climate uncertainties. The framework will be evaluated through piloting for two engineering applications at DoD installations. The expectation is that the framework and assessment products will be appropriate for application to all DoD installations in the geographic study region and elsewhere (although different driving physical processes may apply) after the development and validation conducted in this effort. (Anticipated Project Completion - 2018)