1. Two modes: (1) stop and measure (SAM); (2) drive and measure (DAM). Can do: (1) 1-D transects. (2) 2-D maps. Mobile sensing of surface moisture: COSMOS rover

2. COSMOS rover transect, Hawaii

3. Elevation and forest Rainfall COSMOS rover map, Hawaii

4. One scale: 36 km x 36 km Neutron intensity and water content at four scales: 36 km x 36 km:206 cpm, 14% 9 km x 9 km:206 cpm,14% 3 km x 3 km:199 cpm,15% 1 km x 1 km:209 cpm,13% COSMOS rover map, Oklahoma

5. Monthly maps, except during summer monsoon - weekly. Calibrated at a stationary COSMOS site. COSMOS rover map, Tucson Basin

6. COSMOS rover map, Oklahoma

7. (1) Fast mapping of soil moisture over large areas and over variable terrains (2) Possible with different moving platforms:  cars (done, working well)  aircraft (in progress, likely to work)  on foot (backpack rover)  trains (future, likely to work) Advantages of the COSMOS rover

8. (1) Precision depends on velocity  trade-off between efficiency and precision  and between efficiency and spatial resolution (2) Conversion to soil moisture  usually unalibrated: must use universal calibration  lattice water unknown and variable - must estimate - how?  soil organic C unknown and variable - must estimate - how?  vegetation variable and unknown - must estimate - how?  contribution of road to neutron intensity - how to remove? Challenges unique to the COSMOS rover

9. Lattice water, USA

10. Organic carbon, USA