2011 Annual Report
1a.Objectives (from AD-416)
Soil moisture has been observed using different methodologies; remote sensing using airborne/satellite platforms, intensive ground-based measurements during various field campaigns, and soil moisture monitoring networks. Soil moisture data from remote sensing are usually available at very low spatial resolution and only for a shallow soil depth. In contrast, ground-based and in situ point measurements can extend beyond the rooting zone but are difficult to extrapolate spatially. Reconciling these remote sensing and ground-based, especially in situ networks, each with a different extent, support, and spacing is of paramount significance in the development of robust methodology to predict shallow subsurface soil moisture, surface runoff, and ground water recharge at different spatial scales. This research would establish site specific and generic scaling relationships. This new knowledge would lead to higher spatial resolution information for hydrologic and agricultural decision making.
1b.Approach (from AD-416)
Building on our past/ongoing field campaigns, experience with in situ networks, multi-platform remote sensing campaigns, hydrologic process-based modeling, and data assimilation research, a comprehensive study of soil moisture scaling behavior will be conducted that focuses on the key issues of measurement support size and the precision of in situ and remote sensing platforms. Research would be conducted in the Southern Great Plains (SGP). Networks in the region would be integrated with data from current and future remote sensing platforms that monitor soil moisture at different resolutions. Characterizing the points (accuracy and reliability) and developing techniques for scaling to these diverse resolutions will be accomplished using a number of statistical and modeling approaches and additional intensive observational studies designed to resolve issues with existing infrastructure.
A long history of successful field experiments involving many soil moisture remote sensing techniques over ARS sites in Oklahoma offers the potential to understand how point scale process, as measured by ground sensors, can be used to understand how these relate to satellite-based observations. Cooperators at Texas A&M University are developing data bases and techniques for integrating these different approaches. ARS cooperators have focused on the aircraft results and have planned a series of aircraft-based experiments for irrigated agriculture that will complement other projects being conducted by NASA cooperators. One aircraft flight was successfully conducted in 2010 and a series of ten are planned for the 2011 growing season. Communication consisted of site visits, meetings, and data base development activities. This project will provide a significant step in demonstrating the feasibility of a satellite mission and validating near future missions of opportunity.