patterns, designed to address a number of uncertainties regarding the impact of SST forcing and the role of land-atmosphere feedbacks on regional drought. This talk reviews some of those and related results, with a focus on the U.S. Great Plains, although the basic mechanisms appear to be relevant to drought in many other regions of the world. Issues to be addressed include the seasonality of the global SST response, the impact of soil moisture feedbacks, the potential predictability associated with SST changes, as well as model deficiencies currently limiting our ability to simulate and predict long-term drought.

Do We Need to Put Aquifers into Atmospheric Simulation Models? Evidence for Large Water Table Fluctuations and Groundwater Supported ET under Conditions of Pleistocene and Holocene Climate Change
Mark Person, New Mexico Tech

Aquifer-atmosphere interactions can be important in landscapes where the water table is shallow (<2m) and the watershed topography is gentle. Regional climate models that include aquifer hydrodynamics indicate that between 5 to 20% of evapotranspiration is drawn from the aquifer. The groundwater-supported fraction of evapotranspiration is higher under drought conditions, when evapotranspiration exceeds precipitation. The response time of an aquifer to drought conditions can be long—on the order of 200-500 years—indicating that feedbacks between these two water reservoirs act on disparate timescales. Analysis of Holocene and late Pleistocene paleowater table records suggests that water table fluctuations can be as great as 50 m during drought conditions. With recent advances in the computational power of massively parallel supercomputers, it may soon become possible to incorporate physically based representations of aquifer hydrodynamics into GCM land surface parameterization schemes. This may help to improve our predictions of the long-term consequences of droughts on water resources and climate dynamics.

Breaking the Hydro-Illogical Cycle: The Status of Drought Risk Management in the United States
Mike Hayes, University of Nebraska-Lincoln

This presentation will focus on drought risk management within the United States given the context of climate variability, climate change, and extremes. As the last presentation in the workshop, an attempt will be made to connect comments and issues addressed within previous presentations and breakout groups. A focus will be placed on drought monitoring, impact assessment, mitigation, and planning efforts taking place now across the country, and on suggesting where current efforts need more concentration. The National Integrated Drought Information System (NIDIS) will also be highlighted. Drought fits well into the enhanced efforts by the climate community to create and provide “services” and decision support tools. Each service and tool being designed for drought helps define the “big picture” of drought for policymakers and others who need that scale of information. But they also work to localize drought, putting valuable information in the hands of agricultural producers and community, tribal, and



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