State Water Resources Research Institute Program
Project Id: 2010NC145B
Title: Improved Statewide Soil Moisture Estimation for Hydrologic Assessment and Forecasting
Project Type: Research
Start Date: 3/01/2010
End Date: 2/28/2011
Congressional District: NC-02
Focus Categories: Drought, Hydrology, Water Quantity
Keywords: drought, GIS, rainfall-runoff processes, soil-water relationships, weather data collection, water use monitoring, remote sensing
Principal Investigators: Heitman, Joshua; Austin, Robert E; Boyles, Ryan; White, Jeffrey G
Federal Funds: $ 13,000
Non-Federal Matching Funds: $ 59,265
Abstract: Soil moisture data are useful for applications ranging from construction planning, to turf and crop irrigation scheduling, to initialization of environmental models. However, the value of these data is derived from linking them to areal conditions. The State Climate Office (SCO) of North Carolina (NC) currently provides soil moisture data to the public through the NC Environment and Climate Observing Network (ECONet). The ECONet is a near real-time, point-based, statewide monitoring network. While these data are potentially useful, there is currently no information to confirm or assess whether point observations from the network reflect conditions in the surrounding land area(s). Thus, despite availability of soil moisture data, these data are of limited use for characterizing conditions that contribute to regional storm response and water availability. Within the existing monitoring framework, significant benefits could be achieved by characterizing soil properties at the monitoring sites as they pertain to soil moisture conditions in the surrounding soils. Characterizing relationships of ECONet site soil properties with those in surrounding land units, as well as spatio-temporal correlations among ECONet observations, will facilitate physically-based interpolations to develop spatially and temporally dynamic statewide soil moisture maps. The overarching goal of this project is to improve statewide monitoring, characterization, estimation, and delivery of soil moisture information for a diverse clientele. Specific project objectives are to: 1) characterize soil properties at all ECONet sites; 2) determine the distribution of these sites with respect to major soil-land units; 3) define linkages between ECONet soil moisture observations and surrounding land units; 4) assess spatio-temporal correlations among ECONet observations and use these with information derived from Objective 3 to inform statewide soil moisture interpolation/estimation and produce dynamic maps of soil moisture and related derived products; 5) gauge the potential of satellite passive microwave radiometry and aerial L-band radar to improve spatio-temporal estimation of statewide soil moisture status.
Soils data including soil texture, bulk density, water retention characteristics, and saturated hydraulic conductivity have been collected at 14 of the 36 current ECONet sites. We propose to characterize the remaining 22 sites. These data will be used to develop network metadata, extend current network soil moisture products, and guide spatio-temporal analyses of soil moisture relationships. A hierarchy of currently available georeferenced soil parameters and land cover classes will be used to develop statewide soil-land units (SLU) at multiple scales using a geographic information system (GIS). The SLU will be used with site data to quantify the coverage of current ECONet sites at varying resolutions and derive linkages of properties controlling regional soil moisture status with ECONet data. Using these with point observations of soil moisture and precipitation as inputs, we will develop statewide maps of temporally dynamic soil moisture conditions. We will also conduct temporal geostatistical analyses of ECONet data to characterize spatio-temporal correlations and use them, as possible, to interpolate/estimate soil moisture statewide. We will examine and model relationships of ECONet data and estimated statewide soil moisture with statewide soil moisture data from NASA's Advanced Microwave Scanning Radiometer for Earth Observing System (AMSR-E) on the AQUA satellite. We will also relate data from NASA's Unmanned Aerial Vehicle Synthetic Aperture Radar (UAVSAR), deployed in a piloted aircraft which will overfly ECONet sites periodically, to both ECONet and AMSR-E data. We will thus determine whether remotely sensed soil moisture data can complement ECONet measurements and improve resolution and accuracy of statewide soil moisture estimation for a wide variety of endusers.
Progress/Completion Report, 2010, PDF