Estimation of Soil Profile Water Storage from Limited Sensor Arrays

Abstract:

Soil moisture storage (S) is a fundamental component of the water cycle and is frequently measured to support hydrological models. Vertical profiles of soil moisture sensors are commonly installed as part of monitoring programs to quantify soil moisture status and fluxes. Similarly, remote sensing from satellites holds the promise of providing global data on near surface soil moisture content. We explore the functional relationships between S and point measurements of soil moisture from instrumented profiles near Boise ID and SCAN sites across the USA. The goal is to define opportunities for efficient verification of S and the limits of remote sensing for soil moisture monitoring. The results commonly show hysteresis between soil moisture point measurements at individual depths and S. When the data are parsed by periods of imbibition and drainage, less complex functional relationships emerge. These differ for soil profiles of uniform texture and duplex soils, and provide guidance on data analysis techniques to parameterize hydrologic models with one or two components for S. The implications for optimizing sensor placement within experimental research sites is discussed.