Improved Soil Moisture Products From the North Carolina Environment and Climate Observing Network.

Soil moisture content has important implications for agriculture, hydrology, weather prediction, and climatology. In North Carolina, 20-cm-depth soil moisture data are currently provided by the North Carolina Environment and Climate Observing Network (NCECONet) at 37 stations across the state. Little soils information is available for the monitoring locations in the network. These data are of little value for any applications unless they can be tied to soil and land conditions. This study aims to investigate relationships between soil moisture and site-specific soil and land properties at multiple moisture monitoring sites statewide. Characteristics obtained from on-site samples and/or soil survey data layers were gathered for performing quality assurance and soil series coverage analysis. Metadata were enriched to meet the need for developing useful soil moisture products. The ultimate goal is to predict soil moisture at unmonitored locations through linkages between land-surface properties and soil moisture patterns. Prior research examined a large number of factors including soil texture, vegetation, and precipitation, among others that influence soil moisture. Using these, scientists have tried to build physically realistic models to fit field soil moisture observations. The challenge in our study is that field data are collected over larger spatial extents, encompassing a wide range of soil types and landscapes. Multivariate linear regression is being used to analyze soil and landscape factors affecting soil moisture within the NCECONet coverage area. In the preliminary model, soil moisture was correlated with precipitation, clay content, and Topographic Wetness Index, which quantifies topographic control on hydrological processes. Analysis of variance revealed that clay content had a positive relationship (p ≤ 0.05) with soil moisture content; analysis of other parameters will continue. Our ultimate goal is to provide semi-continuous spatial soil moisture data layers covering the entire state, which will benefit end-users including farmers, engineers, hydrologists, and policy makers.