L-Band Soil Moisture Mapping Using Small UnManned Aerial System
Dai, Eryan 1 ; Gasiewski, Albin 2 ; Stachura, Maciej 3 ; Elston, Jack 4
1 ŷڱƵ University at Boulder
2 ŷڱƵ University at Boulder
3 Black Swift Technologies LLC, Boulder, CO, USA
4 Black Swift Technologies LLC, Boulder, CO, USA
Soil moisture is of fundamental importance to many hydrological, biological and biogeochemical processes, plays an important role in the development and evolution of convective weather and precipitation, and impacts water resource management, agriculture, and flood runoff prediction. The launch of NASA’s Soil Moisture Active/Passive (SMAP) mission in 2015 promises to provide global measurements of soil moisture and surface freeze/thaw state at fixed crossing times and spatial resolutions as low as 5 km for some products. However, there exists a need for measurements of soil moisture on smaller spatial scales and arbitrary diurnal times for SMAP validation, precision agriculture and evaporation and transpiration studies of boundary layer heat transport. The Lobe Differencing Correlation Radiometer (LDCR) provides a means of mapping soil moisture on spatial scales as small as several meters (i.e., the height of the platform) .Compared with various other proposed methods of validation based on either situ measurements or existing airborne sensors suitable for manned aircraft deployment, the integrated design of the LDCR on a lightweight small UAS (sUAS) is capable of providing sub-watershed (~km scale) coverage at very high spatial resolution (~15 m) suitable for scaling scale studies, and at comparatively low operator cost. The LDCR on Tempest unit can supply the soil moisture mapping with different resolution which is of order the Tempest altitude.
The field experiments had been done at Oklahoma in September 8th and 9th, 2015. 5 mapping missions had been achieved in 3 flying tests by using autopilot technology: setting flying altitude and serpentine flying path ahead so the Tempest will cover certain area with desired flying altitude and flying path. The flying altitude of 5 mapping missions are 60m, 35m, 35m, 30m and 30m separately and this can give us soil moisture mapping data with different spatial resolution. The brightness temperature and soil moisture mapping algorithm will be analyzed in the aspect of RFI mitigation. The scientific intercomparisons of LDCR soil moisture with situ measurements will be presented.
McIntyre, E.M., A.J. Gasiewski, and D. Manda D, “Near Real-Time Passive C-Band Microwave Soil Moisture Retrieval During CLASIC 2007,” Proc. IGARSS, 2008.
Robock, A., S. Steele-Dunne, J. Basara, W. Crow, and M. Moghaddam M, “In Situ Network and Scaling,” SMAP Algorithm and Cal/Val Workshop, 2009.
Walker, A., “Airborne Microwave Radiometer Measurements During CanEx-SM10,” Second SMAP Cal/Val Workshop, 2011.