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Harleman Lecture - 2007

'A satellite view of global water and energy cycling'

Dr. Paul R. Houser
Center for Research on Environment and Water
George Mason University
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Speaker Biography
Dr. Houser has an exceptional stature within both the United States and the international scientific community, and his unparalleled professional career provides evidence of his many outstanding qualities and abilities as a world class researcher, teacher and visionary leader. Dr. Houser is an internationally renowned expert in local to global land surface-atmospheric remote sensing, in-situ observation and numerical simulation, development and application of hydrologic data assimilation methods, and global water and energy cycling. He received his B.S. and Ph.D. degrees in Hydrology and Water Resources from the University of Arizona in 1992 and 1996 respectively. His dissertation research, titled "Remote Sensing Soil Moisture using Four-Dimensional Data Assimilation" introduced data assimilation of remotely sensed observations into hydrological models, and demonstrated the benefit of including information from soil moisture observations in land-surface energy and water balance simulations. Dr. Houser joined the NASA/GSFC Hydrological Sciences Branch and the Data Assimilation Office in 1997, and served as Manager of NASA’s Land Surface Hydrology Program from 1999-2000, then served as Branch Head of the Hydrological Science Branch from 2000-2005. During this period he was awarded the Presidential Early Career Award for Scientists and Engineers. This is the highest honor bestowed by the United States government on young professionals at the outset of their independent research careers. In 2005, Paul accepted a position with George Mason University, Climate Dynamics Program as Professor of Global Hydrology, and also formed the new IGES Center for Research on Environment and Water (CREW), with the mission to quantify and predict water cycle and environmental consequences of earth system variability and change through focused research investments in observation, modeling, and application.  Under Dr. Houser’s leadership, CREW has already made significant advances in the use of remote sensing in operational water management decisions, drought monitoring, and delivery of science data and methods to the public. Dr. Houser has considerable expertise and international reputation in the area of water cycle research in response to climate change, such as his 8-year leadership of the NASA Water and Energy cycle Study (NEWS), development of hydrologic data assimilation, work towards water cycle predictability, and improved quantification of global water cycling.  Such research will lead to improved understanding of likely changes in the water cycle in the future, their implications on water resource sustainability, proposed solutions, and development of decision support tools.

Dr. Houser’s specialty is hydrologic observation and numerical simulation, hydrologic data assimilation and global water and energy cycling research. He introduced data assimilation into hydrological models, which has demonstrated real-world hydrologic forecasting improvement. Dr. Houser has led numerous scientific endeavors including the development of Land Data Assimilation Systems (LDAS), the Hydrospheric States Satellite Mission (Hydros), the Land Information System (LIS), the NASA Energy and Water cycle Study (NEWS), and the Water Cycle Solutions Network (WaterNet).

Dr. Houser’s career goal is to continually improve his leadership in global water cycle research of direct relevance to society, including local to global land surface-atmospheric process observation and numerical simulation, and development and application of ecohydrologic data assimilation methods. He is also broadly interested in exploring the physical, spatial, and temporal interconnections between all the earth system components as they relate to the global water and energy cycles. His more specific interests include, water and energy flux studies at various scales including vadose zone, surface, and atmospheric interactions, regional land surface-atmospheric hydrologic modeling, remote sensing, surface flux observation, and near surface soil moisture investigation. He is especially interested in applying cutting-edge research to develop practical solutions to water problems faced by society.

Abstract
Earth is unique due to the abundance and vigorous cycling and replenishing of water. The water cycle operates on a continuum of time and space scales and exchanges large amounts of energy as water undergoes phase changes and is moved from one part of the Earth system to another. Water is essential to life and is central to society’s welfare, progress and sustainable economic growth. However, global water cycle variability which regulates flood, drought, and disease hazards is being continuously transformed by climate, erosion, pollution, salinization, and agriculture and civil engineering practices. The water cycle delivers the consequences of climate variability and change. In fact, the most significant manifestation of climate variation is an intensification of the global water cycle, leading to increased global precipitation, faster evaporation, and a general exacerbation of extreme hydrologic regimes, floods, and droughts. An intensified water cycle would be expected to produce more frequent or severe weather disturbances.

With their unprecedented new observation capacity combined with revolutions in modeling capability, satellite observations have great potential to make huge advances in water and energy cycle prediction. To realize this goal, we must develop a discipline of prediction and verification through the integration of water and energy cycle observations and models, and to verify model predictions against observed phenomena to ensure that research delivers reliable improvements in prediction skill. Accomplishing these goals will require, in part, an accurate accounting of the key reservoirs and fluxes associated with the global water and energy cycle, including their spatial and temporal variability, through integration of all necessary observations and research tools. This challenge is essentially to document and enable improved, observationally-based, predictions of water and energy cycle consequences of Earth system variability and change. This presentation will feature an overview of recent progress towards this challenge, and lay out the plan for coordination with complementary international efforts.