Projection of Ecological Drought Under Climate Change in the Eastern United States

Droughts inflict significant harm to agriculture, infrastructure, and public health. Climate change is likely to drive increases in intensity, frequency, and duration of these events in many parts of the world during the 21^st century. Drought in the eastern U.S. and other humid areas has been historically underrepresented in research; differences in soil characteristics, vegetation cover, aridity regime and precipitation seasonality create unique development, persistence, and resolution of drought events and resulting impacts in these regions. Consequently, humid regions show a tendency towards more frequent, quick developing and shorter duration events than drylands. We explore the characteristics and impacts of ecological drought on predominantly forested regions in the eastern United States in order to constrain the uncertainty of projections for significant drought in the future and provide natural resource managers with relevant information about the drought risks to their systems. We utilize a large ensemble of statistically downscaled global climate model projections from CMIP5 and a suite of vegetation and climate indicators from remote sensing and in-situ observations to identify how drought patterns are best captured across this varied landscape. This involves an exploration of several recently developed ecologically relevant drought indices such as the Evaporative Demand Drought Index (EDDI), Forest Drought Stress Index (FDSI), and Landscape Evaporative Response Index (LERI). By understanding areas of high uncertainty in the drought projections, we can further identify interdisciplinary research needs in climate science, hydrology, and ecology that will make drought identification and projection more relevant and accurate for future ecosystem management.