Opportunities for NASA HQ, CNES, and JPL in WATER HM

1. Opportunities for NASA HQ, CNES, and JPL in WATER HM • U.S.: • Doug Alsdorf, Ohio State University • Dennis Lettenmaier, University of Washington • Lee-Lueng Fu, JPL • Ernesto Rodriguez, JPL • International: • Paul Bates, University of Bristol, UK • Anny Cazenave, LEGOS-CNES • Nelly Mognard, LEGOS-CNES

2. Key Points for Today’s Discussions • Status and update since September 2006 • Risk Reduction & Mission Definition Studies • Form International Joint-Science Working Group

3. Status and Update Since September 2006 • WATER HM is selected by the NRC Decadal Survey (i.e., SWOT) • A new name can be developed if NASA and CNES desire • Wide-swath is the natural follow-on to CNES-NASA partnerships in altimetry • Growth in this partnership now includes surface water hydrology • Surface water has broad community buy-in via NASA SWWG and LEGOS efforts • Hydrology is a topmost priority for CNES • Proposed CNES contributions to WATER HM will be significant, including funding • Both CNES and JPL have made significant contributions to wide-swath development • Need to continue to leverage the NASA and JPL investment in WSOA • WATER HM is a model for bringing together rather different communities toward a single vision • March 2006 Venice meeting was an informal 2-hour meeting organized by CNES • First time hydrology and oceanography brought together • September 2006 Washington D.C. was a formal meeting with very positive results • Recognition that orbits and related temporal sampling are not a constraint against synergies • Spatial resolutions are complementary • Science goals are equally laudable • Joint communities at AGU Fall 2006 San Francisco, March 2008 Ocean Sciences & ASLO • CNES desires full participation with WATER HM • NRC similarly recognized synergies of oceanography and hydrology • Publications since Fall 2006 • Specific to WATER HM: Reviews of Geophysics, Eos • Supporting WATER HM: two in Geophysical Research Letters

4. Risk Reduction andMission Definition Studies • Tidal Aliasing based on swath-altimetry • Sun synchronous vs. non-sun synchronous • Ex: Optimal sampling repeat-period based on non-SS, 78º inclination, profiling altimetry is 21 days • Calibration and error budgets for different spacecraft configurations • New orbit changes the cross-over distribution and frequency compared to the situation studied for WSOA • Quantify residual calibration errors for land DEM based calibration. Issues: • Wet troposphere variations over land • Space-craft stability • Feed results of this study to concurrent spacecraft study to assess feasibility of roll stability given spacecraft power management issues (e.g., solar panel rotation due to non sun-sync orbit) • Atmospheric water vapor corrections • Open oceans corrected with radiometer, not applicable to land • Over land, corrections with SRTM DEM: what is residual error? • Coastal zones remain question – modeling required? More radiometer channels? • Data downlink rates for terrestrial areas • Resolution of 16m x 50m: 22% land surfaces = 140 gigapixels per global map • Resolution of 2m x 30m: All land surfaces = 2470 gigapixels per global map • For comparison: all ocean surface at 1000m x 1000m = 0.35 gigapixels global map • Occasional acquisitions of opportunity over oceans at high resolution • Completion of hydrology virtual mission • Data assimilation published showing capacity to estimate discharge from KaRIN • Now defining trade-offs of discharge & storage change wrt spatial & temporal sampling • Acquisition of Ka-band off-nadir returns from rivers and lakes • Experimental data collected using JPL internal funds in May 2007 • Preliminary results show that the backscatter level will be appropriate for collecting data from space • Water surfaces included two flowing rivers and one reservoir • River flow produces significant roughness, even at low wind speeds

5. International Joint-Science Working Group for WATER HM • SWG Charge: • The SWG is to embark on a mission definition study leading to an optimal preliminary design of the mission given science requirements and technology and cost constraints. • To accomplish the charge: reducing schedule risks • Define the science requirements • These are largely defined, but community buy-in is a continuous & important process • Study the trades in mission constraints vs. science requirements • orbits, sampling aliasing, spacecraft power, onboard memory, station dump, etc. • Terrestrial waters sampling costs and trade-offs • Study mission risks and approach to their reduction • Wet troposphere near coasts, corrections over terrestrial surface waters • Surface wave effects • Internal tide effects • Errors from bank side layover affects • Develop hydrologic processing pathway • Develop processing algorithms for hydrologic data • Structure and costs involved for creating hydrologic data products • Demonstration of potential science and applications • Liaison with and affirm cooperation from water resource managements • Hurricane track prediction • In the U.S.: NOAA, National Weather Service, USGS • Participants in SWG • People from NASA, CNES, JPL, and Universities • SWG links JPL, NASA HQ, CNES, other agencies, international and U.S. communities • Formal recognition allows organized approach to studies, pre-mission meetings and planning, securing of funds

6. Strategy, Timeline • Form Pre-Mission Science Working Group (SWG) by September 2007 • First meeting of SWG Fall 2007 • Conduct risk reduction studies Some are ongoing (ROSES and internal JPL funding) e.g., virtual mission, Ka-band antenna tests from bridges Begin other studies based on SWG recommendations Need to identify a pathway for technology risk reduction funding prior to phase A; is ESTO expecting to perform risk reduction studies for missions endorsed by the decadal review? • Meet with NASA HQ, JPL, CNES prior to completion of the SWG study • Submit SWG report 2008 • Pre-project planning 2009 • Project start 2010

7. Opportunities for NASA HQ, CNES, and JPL in WATER HM • U.S.: • Doug Alsdorf, Ohio State University • Dennis Lettenmaier, University of Washington • Lee-Lueng Fu, JPL • Ernesto Rodriguez, JPL • International: • Paul Bates, University of Bristol, UK • Anny Cazenave, LEGOS-CNES • Nelly Mognard, LEGOS-CNES

8. Key Points for Today’s Discussions • Status and update since September 2006 • Risk Reduction & Mission Definition Studies • Form International Joint-Science Working Group

9. Status and Update Since September 2006 • WATER HM is selected by the NRC Decadal Survey (i.e., SWOT) • A new name can be developed if NASA and CNES desire • Wide-swath is the natural follow-on to CNES-NASA partnerships in altimetry • Growth in this partnership now includes surface water hydrology • Surface water has broad community buy-in via NASA SWWG and LEGOS efforts • Hydrology is a topmost priority for CNES • Proposed CNES contributions to WATER HM will be significant, including funding • Both CNES and JPL have made significant contributions to wide-swath development • Need to continue to leverage the NASA and JPL investment in WSOA • WATER HM is a model for bringing together rather different communities toward a single vision • March 2006 Venice meeting was an informal 2-hour meeting organized by CNES • First time hydrology and oceanography brought together • September 2006 Washington D.C. was a formal meeting with very positive results • Recognition that orbits and related temporal sampling are not a constraint against synergies • Spatial resolutions are complementary • Science goals are equally laudable • Joint communities at AGU Fall 2006 San Francisco, March 2008 Ocean Sciences & ASLO • CNES desires full participation with WATER HM • NRC similarly recognized synergies of oceanography and hydrology • Publications since Fall 2006 • Specific to WATER HM: Reviews of Geophysics, Eos • Supporting WATER HM: two in Geophysical Research Letters

10. Risk Reduction andMission Definition Studies • Tidal Aliasing based on swath-altimetry • Sun synchronous vs. non-sun synchronous • Ex: Optimal sampling repeat-period based on non-SS, 78º inclination, profiling altimetry is 21 days • Calibration and error budgets for different spacecraft configurations • New orbit changes the cross-over distribution and frequency compared to the situation studied for WSOA • Quantify residual calibration errors for land DEM based calibration. Issues: • Wet troposphere variations over land • Space-craft stability • Feed results of this study to concurrent spacecraft study to assess feasibility of roll stability given spacecraft power management issues (e.g., solar panel rotation due to non sun-sync orbit) • Atmospheric water vapor corrections • Open oceans corrected with radiometer, not applicable to land • Over land, corrections with SRTM DEM: what is residual error? • Coastal zones remain question – modeling required? More radiometer channels? • Data downlink rates for terrestrial areas • Resolution of 16m x 50m: 22% land surfaces = 140 gigapixels per global map • Resolution of 2m x 30m: All land surfaces = 2470 gigapixels per global map • For comparison: all ocean surface at 1000m x 1000m = 0.35 gigapixels global map • Occasional acquisitions of opportunity over oceans at high resolution • Completion of hydrology virtual mission • Data assimilation published showing capacity to estimate discharge from KaRIN • Now defining trade-offs of discharge & storage change wrt spatial & temporal sampling • Acquisition of Ka-band off-nadir returns from rivers and lakes • Experimental data collected using JPL internal funds in May 2007 • Preliminary results show that the backscatter level will be appropriate for collecting data from space • Water surfaces included two flowing rivers and one reservoir • River flow produces significant roughness, even at low wind speeds

11. International Joint-Science Working Group for WATER HM • SWG Charge: • The SWG is to embark on a mission definition study leading to an optimal preliminary design of the mission given science requirements and technology and cost constraints. • To accomplish the charge: reducing schedule risks • Define the science requirements • These are largely defined, but community buy-in is a continuous & important process • Study the trades in mission constraints vs. science requirements • orbits, sampling aliasing, spacecraft power, onboard memory, station dump, etc. • Terrestrial waters sampling costs and trade-offs • Study mission risks and approach to their reduction • Wet troposphere near coasts, corrections over terrestrial surface waters • Surface wave effects • Internal tide effects • Errors from bank side layover affects • Develop hydrologic processing pathway • Develop processing algorithms for hydrologic data • Structure and costs involved for creating hydrologic data products • Demonstration of potential science and applications • Liaison with and affirm cooperation from water resource managements • Hurricane track prediction • In the U.S.: NOAA, National Weather Service, USGS • Participants in SWG • People from NASA, CNES, JPL, and Universities • SWG links JPL, NASA HQ, CNES, other agencies, international and U.S. communities • Formal recognition allows organized approach to studies, pre-mission meetings and planning, securing of funds

12. Strategy, Timeline • Form Pre-Mission Science Working Group (SWG) by September 2007 • First meeting of SWG Fall 2007 • Conduct risk reduction studies Some are ongoing (ROSES and internal JPL funding) e.g., virtual mission, Ka-band antenna tests from bridges Begin other studies based on SWG recommendations Need to identify a pathway for technology risk reduction funding prior to phase A; is ESTO expecting to perform risk reduction studies for missions endorsed by the decadal review? • Meet with NASA HQ, JPL, CNES prior to completion of the SWG study • Submit SWG report 2008 • Pre-project planning 2009 • Project start 2010