IMPLICATIONS OF THE NRC DECADAL REVIEW FOR A SWATH ALTIMETRY MISSION

1. Dennis P. Lettenmaier Department of Civil and Environmental Engineering University of Washington for presentation at Ocean Sciences Meeting Orlando March 5, 2008 IMPLICATIONS OF THE NRC DECADAL REVIEW FOR A SWATH ALTIMETRY MISSION

2. ESAS Charge • Recommend a prioritized list of flight missions and supporting activities to support national needs for research and monitoring of the dynamic Earth system during the next decade. • Identify important directions that should influence planning for the decade beyond. Sponsors: NASA SMD, NOAA NESDIS, USGS Geography

3. Executive Committee • Rick Anthes, UCAR, co-chair, atmospheric science • Berrien Moore, U. New Hampshire, co-chair, biogeochemical cycling • Jim Anderson, Harvard, atmospheric science, chemistry • Bruce Marcus, TRW (ret), remote sensing • Bill Gail, Ball Microsoft Virtual Earth, civil space and IT • Susan Cutter, U. South Carolina, hazards and risk • Tony Hollingsworth, ECMWF, weather forecasting • Kathie Kelly, U. Washington, physical oceanography/satellite obs • Neal Lane, Rice, policy • Warren Washington, NCAR, climate • Mary Lou Zoback, RMS, solid earth Panel Chairs • Tony Janetos, PNL/U. Md., ecology and land remote sensing • Brad Hagar, MIT, solid earth • Ruth DeFries, U. Maryland, land cover change and remote sensing • Susan Avery, CIRES and CU, meteorology, space weather • Eric Barron, U. Texas, climate, paleoclimate • Dennis Lettenmaier, U. Washington, hydrology • Mark Wilson, U. Michigan, infectious disease and remote sensing

4. CHALLENGES • Community Buy-in • First decadal survey • Breadth of interests • An organizational challenge was how to cover science/application themes as well as scientific disciplines. In retrospect, having additional discipline-focused subgroups would have been useful • Multi-Agency Issues • Transition to Operations • Sustained Research Operations • Important changes during the study at NASA and NOAA • Budgets • NPOESS • GOES

5. Water Panel top 7 missions • Soil Moisture (SMAP) • Surface water/coastal oceanography (SWOT) • Cold land processes (SCLP) • Groundwater/ocean mass (GRACE+) • Water vapor transport (WOWS/AIRS+) • Glacier mass balance/sea ice thickness • Inland water quality

6. Two main criteria for ranking: a) Scientific benefit b) Societal benefit Weights were equal!

7. Scientific benefits from SWOT (science questions the mission will allow to be addressed): Hydrology: • How much liquid water is stored on Earth’s land surfaces, and what are its dynamics? • How and to what extent do the hydrodynamics of inundated areas control the propagation of flood waves in major rivers, and what are their implications for regional and global carbon and other constituent fluxes?

8. Scientific benefits from SWOT (science questions the mission will allow to be addressed): Oceanography: • What is the small-scale (1-100 km) variability of ocean surface topography that determines the velocity of ocean currents? How are fronts and eddies formed and evolving? How is oceanic kinetic energy dissipated? • What is the synoptic variability of coastal currents? How do the coastal currents interact with the open ocean variability? What are the effects of coastal currents on marine life, ecosystems, waste disposal, and transportation?

9. Societal benefits from SWOT (applications questions) Hydrology: • How much water is stored in the world’s artificial reservoirs, what are its space-time dynamics, and what effect will freely available information about global reservoir storage have on water management, particularly in trans-boundary rivers? • How do the dynamics of seasonally and ephemerally inundated areas affect the propagation of disease vectors, such as malaria, and can knowledge of, and the capability to predict, such dynamics reduce the incidence of waterborne disease?

10. Societal benefits from SWOT (cont.) Oceanography: • Will facilitate societal needs by: • Mapping ocean currents which are needed for shipping and pollutant transport • Analyzing the effects of ocean eddies on marine ecosystems and fisheries • Being used toward possible improvements in hurricane forecasts

11. SWOT Launch 2013-2016 GRACE-II Launch 2016-2020 Changes in aquifers and deep ocean currents River discharge estimates SCLP Launch 2016-2020 Snow pack accumulation and Snowmelt extent Snow water equivalent, snow depth, and snow wetness GPSRO Launch 2010-2013 Pressure/ temperature/ water vapor profiles PATH Launch 2016-2020 Dynamics of water storage in seasonal snow packs Societal Challenge:Freshwater Availability Improved precipitation and drought forecasts to improve water resource management Temperature and humidity profiles

12. FINAL ESAS REPORT • Recommends a path forward that restores U.S. leadership in earth science and applications and averts the potential collapse of the system of environmental satellites • Presents an integrated suite of missions • Panel recommendations rolled-up • Missions sequenced • Overall cost matched to anticipated resources plus reasonable growth • Highest priorities of each panel were preserved • Some guidance on how to handle budget or technology development problems

13. MAIN RECOMMENDATION(for next decade) • NOAA and NASA should undertake a set of 17 recommended missions, phased over the next decade • NASA • 15 missions in small, medium and large categories (de facto prioritized by projected launch dates, SWOT is in 2nd group)

16. Current status and motivationpost-ESAS • SWOT is one of 7 Decadal Review missions for which preliminary planning money is allocated in the Administration 2008 budget. • From standpoint of oceanography, SWOT is the next logical step in a progression that constitutes almost 2 decades of heritage in altimetry. • From the standpoint of hydrology, SWOT will provide the first comprehensive measurements of the dynamics of surface water storage that will motivate new ways of looking at the land surface water cycle, and has a strong applications motivation as well.