1. Contribution of Remote Sensing Technology to Catchment Water Resources Management Toshio Koike 1 and Dara Entekhabi 2 1 University of Tokyo 2 Massachusetts Institute of Technology 5 th IHP/IAHS George Kovacs Colloquium June 2-3, 2000

2. Outline: Definitions: What is needed? What is measured? What is available? Case examples. What are the challenges? Science. Application. What is the next step?

3. “In the history of the hydrologic sciences as in other sciences, most of the significant advances have resulted from new measurements.” p.214, Opportunities in the Hydrologic Sciences, NAS, 1991. New data types force the rethinking of conceptual frameworks and analysis approaches in science as well as in applications.

4. What hydrometric data is needed for catchment management? Site characterization: Topography and drainage Land use Geology Hydrologic inputs: Rainrate Snowpack Losses: Evapotranspiration River discharge Status: Flood inundation Soil moisture Crop conditions Water turbidity

5. Remote Sensing vs. in situ Emerging technological advances in sensors and remote platforms allow measurements with coverage, and cost- and quality-effectiveness exceeding in situ networks. The steps to using remote sensing measurements: Geophysical inversion: Relate spectral radiation to relevant variable Resolution: Interpretation of measurement that is area-effective

6. Characterization: Digital elevation and land use classification at 25m resolution globally Hydrologic Inputs: Rainrate and snowpack at 2 to 25 km upto 6-hourly Losses: Evaporation and discharge are TBD Status: Flood inundation now possible at 10m Soil moisture TBD but tens of kilometers

7. Shuttle Radar Topography Mission (SRTM)

8. Up to 30 m resolution classification and monitoring of vegetation and crops

9. Rainrate with complete spatial coverage

11. What are the challenges? Hydrologic Science and Remote Sensing Technology Interpretation of areal measurements in the presence of spatial variations Added-value data products from merging hydrologic models and measurements Applications to Catchment Water Management Mapped attributes and spatial information systems as the analysis framework Re-examine monitoring  assessment  control in the context of this new data type

12. Next step? In the context of a demonstration basin: Measure the cost-effectiveness of relying on remotely sensed data Measure the influence of (internal) spatial interactions in resource use